CN222721362U

CN222721362U - Starting circuit of power management chip, power conversion equipment and energy storage equipment

Info

Publication number: CN222721362U
Application number: CN202420400997.9U
Authority: CN
Inventors: 杨星星; 宋苏; 古涛
Original assignee: Solax Power Network Technology Zhejiang Co Ltd
Current assignee: Solax Power Network Technology Zhejiang Co Ltd
Priority date: 2024-03-01
Filing date: 2024-03-01
Publication date: 2025-04-04
Anticipated expiration: 2034-03-01

Abstract

The present application provides a startup circuit, a power conversion device and an energy storage device for a power management chip. In the startup circuit, the first switch circuit is used to connect when a DC input voltage is connected, and output a first output voltage. The second switch circuit is connected to the first switch circuit through a startup resistor, and the second switch circuit is also connected to the power pin of the power management chip. The second switch circuit is used to connect when the first switch circuit outputs the first output voltage and the switching power supply is not working, and output the startup voltage to the power pin to start the power management chip. The control circuit is used to control the second switch circuit to disconnect when the switching power supply is working, so that the startup resistor is disconnected from the power pin. The power supply circuit is used to power the power management chip when the switching power supply is working. The startup circuit of the present application generates less loss, which is conducive to improving the startup efficiency of the power management chip and widening the input voltage range, and is conducive to extending the service life of the battery in the battery application scenario.

Description

Starting circuit of power management chip, power conversion equipment and energy storage equipment

Technical Field

The application relates to the technical field of power supplies, in particular to a starting circuit of a power management chip, power conversion equipment and energy storage equipment.

Background

The power management chip plays a vital role as a control chip of the switching power supply. The power pin of the power management chip is connected with the starting circuit, and the starting circuit can provide required voltage for the power management chip after power connection so that the power management chip can start and work. The conventional start-up circuit is constituted by a start-up resistor. The resistance value and the power of the starting resistor are selected according to the starting current, the direct current input voltage and the starting time of the power management chip. If the selected resistance value is large, the voltage charging time is long, and if the resistance value is too large, the starting current may not be reached, and the power management chip cannot work. Therefore, when the voltage is input in a wide range, the starting resistor is usually selected to have a smaller resistance value in order to ensure that the power management chip can be started normally during low-voltage input. However, the starting resistor is very large in loss caused by high voltage input, and is not well designed and is easy to overheat and damage when high voltage is input. Particularly in battery applications, the start-up circuit is always active and consumes battery power. When the battery is in shortage, the starting circuit can thoroughly discharge the electricity of the battery, so that the battery is damaged.

Disclosure of utility model

In view of this, the application provides a power management chip starting circuit, a power conversion device and an energy storage device, which can effectively reduce loss, is beneficial to improving the starting efficiency of the power management chip and widening the input voltage range, and is beneficial to prolonging the service life of a battery under the application scene of the battery.

The first aspect of the application provides a starting circuit of a power management chip, wherein a control pin of the power management chip is connected to a switching power supply and used for controlling the switching power supply to work after starting, the starting circuit comprises a first switching circuit, a starting resistor, a second switching circuit, a control circuit and a power supply circuit, the first switching circuit is used for being communicated when a direct current input voltage is accessed and outputting a first output voltage, the second switching circuit is connected to the first switching circuit through the starting resistor and is also connected to a power pin of the power management chip, the second switching circuit is used for being communicated when the first switching circuit outputs the first output voltage and the switching power supply is not working and outputting the starting voltage to the power pin, the starting voltage is used for starting the power management chip, the control circuit is connected with the switching power supply and the second switching circuit and used for controlling the second switching circuit to be disconnected when the switching power supply works, and the power supply circuit is connected to the power pin and the switching power supply and is used for outputting a second output voltage to the power pin when the switching power supply works, and the power management chip is supplied.

In one embodiment, the second switching circuit comprises a depletion type switching tube, a first anti-reflection diode and a voltage dividing circuit, wherein a first connecting end of the depletion type switching tube is connected with a cathode of the first anti-reflection diode, an anode of the first anti-reflection diode is connected to the first switching circuit through a starting resistor, a second connecting end of the depletion type switching tube is connected to the control circuit through the voltage dividing circuit, a control end of the depletion type switching tube is connected to the voltage dividing circuit, a second connecting end of the depletion type switching tube is also connected to a power pin, the depletion type switching tube is used for outputting a first output voltage when the first switching circuit is not in operation and is turned on and outputting a starting voltage to the power pin, and the depletion type switching tube is used for being turned off and stopping outputting the starting voltage when the switching power supply is in operation.

In one embodiment, the first switching circuit comprises an enhanced switching tube, a first current limiting resistor and a voltage stabilizing circuit, wherein a first connecting end of the enhanced switching tube is connected with the first current limiting resistor and the voltage stabilizing circuit, the first current limiting resistor and the voltage stabilizing circuit are used for being connected with direct current input voltage, a second connecting end of the enhanced switching tube is connected with a starting resistor, a control end of the enhanced switching tube is connected with the voltage stabilizing circuit, and the enhanced switching tube is used for being conducted when the direct current input voltage is connected with the first output voltage and outputting the first output voltage to the starting resistor.

In one embodiment, the sum of the withstand voltage value of the depletion switching transistor and the withstand voltage value of the enhancement switching transistor is not smaller than the direct current input voltage.

In one embodiment, the depletion type switching transistor is further configured to output a constant start-up current to the power supply pin when the first switching circuit outputs the first output voltage and the switching power supply is not operated.

In one embodiment, the control circuit comprises a driving switch tube, a second anti-reflection diode and an anti-interference circuit, wherein a first connecting end of the driving switch tube is connected to the second switch circuit, a second connecting end of the driving switch tube is connected to the second switch circuit and the ground, a control end of the driving switch tube is connected to the second connecting end of the driving switch tube and a cathode of the second anti-reflection diode through the anti-interference circuit, an anode of the second anti-reflection diode is connected to the switching power supply, the driving switch tube is used for being conducted when the switching power supply works so as to be connected with the voltage dividing circuit into a loop, so that a driving voltage generated by the voltage dividing circuit is connected between the control end of the depletion type switch tube and the second connecting end of the depletion type switch tube, and the driving voltage is used for driving the depletion type switch tube to be turned off.

In one embodiment, the voltage dividing circuit comprises a first voltage dividing resistor and a second voltage dividing resistor, one end of the first voltage dividing resistor is connected to the second connecting end of the depletion type switching tube, and the other end of the first voltage dividing resistor is connected to the control end of the depletion type switching tube and is connected to the control circuit through the second voltage dividing resistor.

In one embodiment, the power supply circuit includes a rectifying circuit and a third anti-reverse diode, the rectifying circuit is connected between an anode of the third anti-reverse diode and the switching power supply, and a cathode of the third anti-reverse diode is connected to the power supply pin.

A second aspect of the application provides a power conversion apparatus. The power conversion device comprises a switching power supply, a power management chip and a starting circuit, wherein the starting circuit is connected with a power pin of the power management chip, and a control pin of the power management chip is connected with the switching power supply.

A third aspect of the application provides an energy storage device. The energy storage device comprises a battery pack, a switching power supply, a power management chip and the starting circuit according to the first aspect or any one of the embodiments of the first aspect, wherein the power pins of the battery pack and the power management chip are respectively connected with the starting circuit, and the control pin of the power management chip is connected with the switching power supply.

Compared with the prior art, the application has at least the following advantages:

1. The starting circuit can start the power management chip, and after the power management chip is started, the starting circuit can automatically cut off the second switching circuit and the starting resistor and can be switched to supply power for the power management chip by the switching power supply. In this way, the starting resistor will not consume electric energy after the power management chip is started, and therefore, the loss generated by the starting circuit can be reduced.

2. In the starting circuit of the application, the enhancement type switching tube in the first switching circuit and the depletion type switching tube in the second switching circuit are connected in series. Therefore, the enhancement type switching tube and the depletion type switching tube can jointly bear direct current input voltage, so that the voltage born by the enhancement type switching tube and the depletion type switching tube can be reduced, and the overvoltage risk is reduced. In addition, the enhancement type switching tube and the depletion type switching tube can adopt semiconductor devices with smaller withstand voltage values, so that the cost can be reduced, and the selection of the types is more convenient. In addition, the withstand voltage values of the enhancement type switching tube and the depletion type switching tube can also have larger allowance, so that the input voltage range of the starting circuit is widened, wide voltage input and high voltage input are realized, and in the case of high input voltage, the overvoltage risk of the switching device is low, and the overheat damage risk of the starting resistor is low. Therefore, the circuit design is easy to implement and has a wide application range.

3. In the starting circuit, the enhanced switching tube is a normally closed switch, so that abnormal conduction of the switching tube in the first switching circuit due to noise interference can be avoided under the condition that the direct current input voltage is not connected or the connected voltage does not reach the direct current input voltage.

4. In the starting circuit, the depletion type switching tube is a normally open switch, so that the time for waiting for the conduction of the depletion type switching tube can be saved when the starting circuit is connected with direct current input voltage, the power supply pin of the power supply management chip can be supplied with power more quickly, and the starting efficiency can be improved.

5. When the starting circuit is applied to energy storage equipment (namely, a battery scene), the starting circuit does not consume the electric quantity of the battery pack because the enhanced switch tube is turned off before the power management chip is started. In the process of starting the power management chip, the starting circuit can rapidly provide starting voltage and constant current starting current, so that the starting time of the power management chip is short and the efficiency is high. After the power management chip is started, the starting circuit can automatically turn off the depletion type switching tube, so that the starting circuit causes little electric quantity loss of the battery pack, and the efficiency of the energy storage device is facilitated. Therefore, the energy storage device can be standby with ultra-low power consumption under the condition of long-term standby of the energy storage device. Under the condition that the battery pack is deficient in electricity (namely, the electricity is insufficient), the electricity of the battery pack is not easy to be exhausted, and therefore the battery pack can be prevented from being damaged due to the fact that the electricity is exhausted.

Drawings

Fig. 1 is a circuit diagram of a conventional starting circuit.

Fig. 2 is a schematic diagram of a connection of a start-up circuit according to an embodiment of the present application.

Fig. 3 is a circuit diagram of a starting circuit according to an embodiment of the present application.

Fig. 4 is a schematic diagram of a power conversion apparatus according to an embodiment of the present application.

Fig. 5 is a schematic diagram of an energy storage device according to an embodiment of the present application.

Description of the main reference signs

Starting circuit 100

First switch circuit 11

Voltage stabilizing circuit 111

Overvoltage protection circuit 112

Starting resistor 12

Second switch circuit 13

Voltage dividing circuit 131

Power supply circuit 14

Rectifying circuit 141

Control circuit 15

Anti-interference circuit 151

Power management chip 200

Switching power supply 300

DC power supply 400

Battery pack 500

Power conversion apparatus 1000

Energy storage device 2000

Detailed Description

In order that those skilled in the art will better understand the present application, a technical solution in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present application without making any inventive effort, shall fall within the scope of the present application. The different embodiments and features of the embodiments described below can be combined with each other without conflict.

The power management chip plays a vital role as a control chip of the switching power supply. Referring to fig. 1, a power pin VCC of a power management chip is connected to a start circuit, and the start circuit can provide a required voltage for the power management chip after power connection, so that the power management chip can start and operate. The conventional starting circuit is composed of starting resistors (such as resistors R1 and R2 connected in series in fig. 1).

The resistance value and the power of the starting resistor are selected according to the starting current, the direct current input voltage and the starting time of the power management chip. If the selected resistance is large, the voltage charging time is long, and the efficiency is affected. If the resistance is too large, the start-up current may not be reached and the power management chip will not work. Therefore, when the voltage is input in a wide range, the starting resistor is usually selected to have a smaller resistance value in order to ensure that the power management chip can be started normally during low-voltage input. However, the starting resistor is very large in loss caused by high voltage input, and is not well designed and is easy to overheat and damage when high voltage is input. Particularly in battery applications, the start-up circuit is always active and consumes battery power. When the battery is in shortage, the starting circuit can thoroughly discharge the electricity of the battery, so that the battery is damaged.

Therefore, the embodiment of the application provides a starting circuit of a power management chip, which can effectively reduce loss, is beneficial to improving the starting efficiency of the power management chip and widening the direct current input voltage range, and is beneficial to prolonging the service life of a battery under the application scene of the battery.

Specifically, please refer to fig. 2, which is a schematic diagram illustrating a connection of a start-up circuit according to an embodiment of the present application.

As shown in fig. 2, the start-up circuit 100 is connected to a power pin VCC of the power management chip 200 and a dc power supply 400. The start-up circuit 100 may access the dc input voltage from the dc power supply 400 and generate a start-up voltage required for starting up the power management chip 200 to the power management chip 200. It is understood that the power pin VCC of the power management chip 200 may be grounded through the storage capacitor Cvcc, which acts as a voltage regulator. The control pin OUT of the power management chip 200 is connected to the switching power supply 300. After the power management chip 200 is started, the control pin OUT of the power management chip can output a control signal to the switching power supply 300 to control the switching power supply 300 to work. The power pin VCC of the power management chip 200 is also connected to the switching power supply 300, so that the power management chip 200 may also be powered by the operating switching power supply 300.

The dc power supply 400 may be, for example, a battery pack, a rectifying circuit, or other devices/modules/circuits/elements that may provide dc power. The switching power supply 300 may be configured according to practical needs, and may include an isolated power conversion circuit (including a transformer), for example.

The power management chip 200 may be, for example, a PWM (Pulse Width Modulation ) chip. It should be understood that the pin numbers of the power management chip 200 shown in fig. 2 are only examples, and do not constitute a specific limitation on the embodiments of the present application. In practical applications, the functions of the pins shown in fig. 2 may also be implemented using other numbered pins of the power management chip 200.

Referring to fig. 3, the start-up circuit 100 according to the embodiment of the application may include a first switch circuit 11, a start-up resistor 12, a second switch circuit 13, a control circuit 15, and a power supply circuit 14.

The first switching circuit 11 is connected to the dc power supply 400, and the first switching circuit 11 is connected to the second switching circuit 13 through the start resistor 12. When the dc power supply 400 supplies the dc input voltage Vin, the first switch circuit 11 is connected and outputs the first output voltage Vo1. At this time, the voltage across the start resistor 12 is Vo1 (neglecting the line resistance). The second switching circuit 13 taps the voltage Vo1 of the start resistor 12. In contrast, when the dc power supply 400 does not provide the dc input voltage Vin, the first switch circuit 11 is turned off, and cannot output the first output voltage Vo1, and the second switch circuit 13 is not connected to the first output voltage Vo1.

The control circuit 15 connects the switching power supply 300 and the second switching circuit 13. When the switching power supply 300 is operated, the control circuit 15 controls the second switching circuit 13 to be turned off (the control circuit 15 at this time may be powered by the switching power supply 300). Conversely, when the switching power supply 300 is not operating, the control circuit 15 cannot control the second switching circuit 13 to be turned off (the control circuit 15 at this time loses the power supply of the switching power supply 300).

The second switching circuit 13 is also connected to the power supply pin VCC of the power management chip 200. When the second switch circuit 13 receives the first output voltage Vo1 (i.e., the first switch circuit 11 outputs the first output voltage Vo 1) and the switch power supply 300 is not operated, the second switch circuit 13 is connected and outputs a start voltage to the power pin VCC, and the start voltage is used for starting the power management chip 200. In contrast, when the switching power supply 300 operates, the second switching circuit 13 is turned off, and the start-up voltage cannot be output. At this time, the starting resistor 12 is off (i.e., the starting resistor 12 is disconnected from the second switch circuit 13 and the power supply pin VCC).

The power supply pin VCC of the power management chip 200 is also connected to the switching power supply 300 through the power supply circuit 14. When the switching power supply 300 operates, the power supply circuit 14 may output the second output voltage Vo2 to the power supply pin VCC to supply power to the power management chip 200.

It should be understood that the specific structures of the first switch circuit 11, the starting resistor 12, the second switch circuit 13, the control circuit 15, and the power supply circuit 14 are not limited in the embodiment of the present application, as long as the first switch circuit 11, the starting resistor 12, the second switch circuit 13, the control circuit 15, and the power supply circuit 14 can realize corresponding functions. For a better understanding, the start-up circuit 100 is described in detail below in connection with the specific circuit example shown in fig. 3.

Specifically, as shown in fig. 3, the first switching circuit 11 may include an enhanced switching transistor Q1, a first current limiting resistor, and a voltage stabilizing circuit 111. The enhancement type switching tube Q1 may be an enhancement type MOS tube, and fig. 3 illustrates an example in which the enhancement type switching tube Q1 is an enhancement type NMOS tube. The control end of the enhancement type MOS tube is a grid electrode, the first connecting end of the enhancement type MOS tube is a drain electrode, and the second connecting end of the enhancement type MOS tube is a source electrode. It is understood that the enhanced NMOS tube is a normally closed switch. The first current limiting resistor may comprise a resistive element, or a plurality of resistive elements connected in series, parallel, or series-parallel, and is illustrated in fig. 3 as the first current limiting resistor being resistor R3. The voltage stabilizing circuit 111 may be any circuit capable of realizing a voltage stabilizing function, and the voltage stabilizing circuit 111 illustrated in fig. 3 includes a second current limiting resistor R2 and a first zener diode ZD1. The structure and the resistance of the starting resistor 12R4 may be set according to practical needs, and are not limited herein, and fig. 3 illustrates that the starting resistor 12 is the resistor R4.

The first connection terminal of the enhanced switching tube Q1 is connected to the positive pole (DC+), the negative pole (DC-) of the DC power supply 400 via a first current limiting resistor R3, and the negative pole (DC-) of the DC power supply 400 is grounded. One end of the second current limiting resistor R2 is connected to the positive electrode of the direct current power supply 400, the other end of the second current limiting resistor R2 is connected to the cathode of the first zener diode ZD1 and the control end of the enhanced switching tube Q1, and the anode of the first zener diode ZD1 is grounded. The second connection terminal of the enhanced switching transistor Q1 is connected to the start-up resistor R4.

The first current limiting resistor R3 may limit the current on the first connection terminal of the enhancement switch tube Q1 to prevent the enhancement switch tube Q1 from being damaged by overcurrent. The first zener diode ZD1 can stabilize the voltage and current at the control terminal of the enhancement switch tube Q1, and prevent the enhancement switch tube Q1 from being damaged by overstress. The second current limiting resistor R2 may limit the current of the first anti-reverse diode ZD1 to prevent the first anti-reverse diode ZD1 from being damaged by overcurrent. It can be appreciated that the resistance of the second current limiting resistor R2 may be very large, but too large a resistance may result in a smaller voltage stabilizing value of the voltage stabilizing tube, which may result in a higher voltage across the enhancement switch tube Q1, so that a suitable resistance value needs to be selected in combination with the characteristics of the first zener diode ZD1 and the withstand voltage value of the enhancement switch tube Q1. When the dc input voltage Vin is higher than the regulated voltage V1 of the first zener diode ZD1, the second current limiting resistor R2 generates power consumption p= (Vin-V1) × (Vin-V1)/R2.

In an embodiment, an overvoltage protection circuit 112 may also be connected between the control terminal and the second connection terminal of the enhanced switching tube Q1. As shown in fig. 3, the overvoltage protection circuit 112 may include, for example, a first filter capacitor C1 and a second zener diode ZD2 connected in parallel, where the first filter capacitor C1 may smooth a voltage between the control terminal and the second connection terminal of the enhancement switch tube Q1, and the second zener diode ZD2 may stabilize a voltage between the control terminal and the second connection terminal of the enhancement switch tube Q1, so that overvoltage damage of the enhancement switch tube Q1 may be prevented.

With continued reference to fig. 3, the second switching circuit 13 may include a depletion type switching transistor Q2, a first anti-reflection diode D2, and a voltage dividing circuit 131. The depletion type switching transistor Q2 may be a depletion type MOS transistor, and in fig. 3, the depletion type switching transistor Q2 is shown as an example of a depletion type NMOS transistor. The control end of the depletion MOS tube is a grid electrode, the first connecting end of the depletion MOS tube is a drain electrode, and the second connecting end of the depletion MOS tube is a source electrode. It will be appreciated that the depletion switch Q2 itself is in communication and is therefore a normally open switch. The voltage dividing circuit 131 may be any circuit capable of realizing a voltage dividing function, and the voltage dividing circuit 131 illustrated in fig. 3 includes a first voltage dividing resistor R5 and a second voltage dividing resistor R6.

The first connecting end of the depletion type switching tube Q2 is connected with the cathode of the first anti-reflection diode D2, and the anode of the first anti-reflection diode D2 is connected to the second connecting end of the enhancement type switching tube Q1 through the starting resistor R4. Therefore, the depletion switching transistor Q2 and the enhancement switching transistor Q1 are connected in series. The second connection end of the depletion type switching tube Q2 is connected with one end of a first voltage dividing resistor R5, the other end of the first voltage dividing resistor R5 is connected with the control end of the depletion type switching tube Q2, and the second connection end of the depletion type switching tube Q2 is connected to the control circuit 15 through a second voltage dividing resistor R6. The second connection terminal of the depletion switch Q2 is also connected to the power pin VCC of the power management chip 200.

The first anti-reflection diode D2 can realize an anti-reflection function by utilizing unidirectional conductivity thereof to protect the enhancement type switching tube Q1 and the depletion type switching tube Q2. In addition, a third current limiting resistor R7 may be further disposed between the second connection end of the depletion type switching tube Q2 and the power supply pin VCC, where the third current limiting resistor R7 may limit the current on the second connection end of the depletion type switching tube Q2 and the power supply pin VCC, so as to prevent the depletion type switching tube Q2 and the power supply pin VCC from being damaged due to overcurrent.

Referring to fig. 3 again, the power supply circuit 14 may include a rectifying circuit 141 and a third anti-reflection diode D5. The rectifying circuit 141 may be any circuit capable of realizing a rectifying function. For ease of understanding, the rectifying circuit 141 in fig. 3 is shown as including a rectifying diode D4 and a fifth filter capacitor C5. The anode of the rectifying diode D4 is connected to the switching power supply 300, and the cathode of the rectifying diode D4 is grounded through the fifth filter capacitor C5. The cathode of the rectifying diode D4 is connected to the anode of the third anti-reflection diode D5 and the control circuit 15. The cathode of the third anti-reverse diode D5 is connected to the power pin VCC of the power management chip 200. Therefore, the voltage output by the switching power supply 300 may be rectified by the rectifying circuit 141 and then transferred to the control circuit 15, and then transferred to the power pin VCC through the third anti-reverse diode D5. The voltage received by the power supply pin VCC is equal to the voltage output by the switching power supply 300 minus the conduction voltage drop of the rectifying diode D4 and the conduction voltage drop of the third anti-reflection diode D5. Here, the rectifying circuit 141 may convert the voltage of the switching power supply 300 into a direct current voltage. The third anti-reflection diode D5 can not only transmit voltage but also play an anti-reflection role.

As previously described, the switching power supply 300 may include an isolated power conversion circuit that includes a transformer. Thus, in the present embodiment, as shown in fig. 3, the anode of the rectifying diode D4 may be an auxiliary winding output terminal connected to a transformer in the switching power supply 300, and is connected to the voltage Vaux output from the auxiliary winding. Of course, in other embodiments, the anode of the rectifying diode D4 may be connected to other elements, modules or circuits in the switching power supply 300, as long as the switching power supply 300 is capable of outputting an appropriate voltage to the power supply circuit 14 after being started. In an embodiment, the rectifying circuit 141 may also be integrated in the switching power supply 300, so the power supply circuit 14 may omit the rectifying circuit 141.

As shown in fig. 3, the control circuit 15 includes a driving switching tube Q3, a second anti-reverse diode D3, and an anti-interference circuit 151. For convenience of description, fig. 3 illustrates that the driving switch Q3 is a low-voltage transistor. The control end of the triode is a base electrode, the first connecting end of the triode is a collector electrode, and the second connecting end of the triode is an emitter electrode. It will be appreciated that the drive switch Q3 is a normally closed switch. The anti-interference circuit 151 may be any circuit capable of implementing an anti-interference function, and the anti-interference circuit 151 illustrated in fig. 3 includes a first filter resistor R8, a second filter resistor R9, and a second filter capacitor C3.

The first connection terminal of the driving switch tube Q3 is connected to the second voltage dividing resistor R6, so as to be connected with the control terminal of the depletion switch tube Q2 through the second voltage dividing resistor R6. The second connection terminal of the driving switching transistor Q3 is connected to the second connection terminal of the depletion switching transistor Q2 and to ground. The control end of the driving switch tube Q3 is connected to the second connection end of the driving switch tube Q3 and the ground through a second filter resistor R9, and is connected to the cathode of the second anti-reflection diode D3 through a first filter resistor R8. The second filter capacitor C3 is connected in parallel with the second filter resistor R9, that is, the second filter capacitor C3 is connected between the control terminal of the driving switch Q3 and the ground. The anode of the second anti-reflection diode D3 is connected to the cathode of the rectifying diode D4 in the power supply circuit 14.

The first filter resistor R8, the second filter resistor R9 and the second filter capacitor C3 form an RC low-pass filter circuit, which can be used to filter high-frequency interference caused by the switching power supply 300, so as to avoid the influence of the high-frequency interference on the normal on-off of the driving switch tube Q3. In an embodiment, the anode of the second anti-reflection diode D3 may be further connected to the third filter capacitor C4, the cathode of the second anti-reflection diode D3 may be further connected to the fourth filter capacitor C2, and the third filter capacitor C4 and the fourth filter capacitor C2 may further enhance the filtering effect. In addition, a third zener diode ZD3 may be connected between the second connection terminal of the driving switching tube Q3 and the second connection terminal of the depletion switching tube Q2. The third zener diode ZD3 can stabilize the voltage on the power pin VCC to avoid over-voltage damage of the power management chip 200.

Based on the circuit design shown in fig. 3, the operation of the start-up circuit 100 is specifically as follows:

In the case where neither the switching power supply 300 nor the power management chip 200 is started, the power supply circuit 14 and the control circuit 15 have no voltage input, and the driving switching transistor Q3, the second anti-reflection diode D3, and the third anti-reflection diode D5 in the control circuit 15 cannot be turned on, so that neither the control circuit 15 nor the power supply circuit 14 is operated, or that is, both the control circuit 15 and the power supply circuit 14 are turned off.

When the first switch circuit 11 is connected to the dc power supply 400 and the dc power supply 400 provides the dc input voltage Vin, the control terminal and the first connection terminal of the enhancement switch Q1 in the first switch circuit 11 have voltage inputs, so that the enhancement switch Q1 can be switched from an off state to an on state, and the second connection terminal thereof can output the first output voltage Vo1 to the start resistor R4. The voltage of the start resistor R4 is the first output voltage Vo1. The first output voltage Vo1 is equal to a difference between the dc input voltage Vin and the turn-on threshold voltage of the enhancement switch transistor Q1.

Furthermore, the first connection terminal of the depletion type switching transistor Q2 in the second switching circuit 13 may be connected to the first output voltage Vo1 of the starting resistor R4 through the first anti-reflection diode D2, and neither the control terminal nor the second connection terminal of the depletion type switching transistor Q2 has a voltage. Therefore, when the first switching circuit 11 outputs the first output voltage Vo1 and the switching power supply 300 is not operated, the depletion type switching tube Q2 is in a natural conduction state, and the second connection terminal thereof can output the start-up voltage and the start-up current to the power supply pin VCC, and the capacitor Cvcc on the power supply pin VCC can be charged and stored. In addition, the starting voltage can also be transmitted to the first connection end of the driving switch tube Q3 in the control circuit 15 through the first voltage dividing resistor R5 and the second voltage dividing resistor R6.

It should be understood that, at this time, neither the control terminal nor the second connection terminal of the depletion type switching transistor Q2 is connected to a voltage, that is, vgs=0v, so that the depletion type switching transistor Q2 can be equivalently used as a constant current source, and can output a constant starting current to the power supply pin VCC to charge the capacitor Cvcc in a constant current manner, so that the problem of current spike can be avoided, and the charging time of the capacitor Cvcc can be substantially consistent regardless of whether the dc input voltage Vin is high or low. The constant starting current is Vo1/R4, and the current can be adjusted by selecting corresponding device parameters according to actual requirements.

It can be appreciated that if the dc power supply 400 does not provide the dc input voltage Vin, the enhancement switch Q1 remains off, and thus the depletion switch Q2 cannot output voltage and current.

When the voltage of the capacitor Cvcc is charged to the start-up voltage required by the power management chip 200, the power management chip 200 can be started up. The power pin VCC of the power management chip 200 after the start-up has an operating current flowing therethrough, and the power management chip 200 generates a control signal and outputs the control signal to the switching power supply 300 through the control pin OUT. The switching power supply 300 is started and starts to operate under the control of the control signal, so that the voltage Vaux output by the switching power supply 300 rises and stabilizes at a certain voltage value.

The voltage Vaux output from the switching power supply 300 may be rectified by the rectifying circuit 141. Since the rectified voltage is greater than the conduction voltage drop of the second anti-reflection diode D3 in the control circuit 15, the rectified voltage can be transmitted to the control end of the driving switch tube Q3 through the second anti-reflection diode D3 and the first filter resistor R8 of the anti-interference circuit 151, so that the driving switch tube Q3 can be switched from the off state to the on state. Therefore, the driving switch Q3 may be connected to the voltage dividing circuit 131 (i.e. the first voltage dividing resistor R5 and the second voltage dividing resistor R6) in a loop. Therefore, the working current of the power management chip 200 may flow from the power supply pin VCC to the third current limiting resistor R7, and after passing through the third current limiting resistor R7, the first voltage dividing resistor R5 and the second voltage dividing resistor R6, the voltage VGS between the control terminal and the second connection terminal of the depletion switch Q2 is equal to the voltage across the first voltage dividing resistor R5 through the turned-on driving switch Q3 to the ground GND, that is, vgs= -VCC/(r5+r6) ×r5.

When the VGS absolute value of the depletion type switching transistor Q2 is greater than the off threshold voltage of the depletion type switching transistor Q2, the communication of the depletion type switching transistor Q2 is gradually depleted, and thus the depletion type switching transistor Q2 is switched from the on state to the off state, and the output voltage and current to the power pin VCC are stopped. Therefore, the second switching circuit 13 stops supplying power to the power management chip 200. The start resistor 12 is disconnected from the second switch circuit 13 and the power supply pin VCC at this time. It can be seen that this voltage VGS is used to drive the depletion switch Q2 off, and thus this voltage VGS may be referred to as the drive voltage.

Meanwhile, the voltage Vaux output by the switching power supply 300 is rectified and then transferred to the third anti-reflection diode D5, and the third anti-reflection diode D5 transfers the second output voltage Vo2 to the power supply pin VCC, so that the switching power supply 300 can supply power to the power management chip 200 through the power supply circuit 14. Wherein the second output voltage Vo2 is equal to the rectified voltage of the switching power supply 300 minus the conduction voltage drop of the third anti-reflection diode D5.

It can be seen that the starting circuit 100 can be used to start the power management chip 200, and after the power management chip 200 is started, the starting circuit 100 can automatically cut off the second switching circuit 13 and the starting resistor 12, and can switch to supply power to the power management chip 200 by the switching power supply 300.

It will be appreciated that in the case where the depletion type switching transistor Q2 is turned off, the starting resistor 12 is disconnected from the second switching circuit 13 and the power supply pin VCC, and no current flows through the starting resistor 12, so that no more power is consumed, and thus, the loss generated by the starting circuit 100 can be reduced. In this case, the starting circuit 100 still has the second current limiting resistor R2 and the first zener diode ZD1 in the first switch circuit 11, and the first voltage dividing resistor R5 and the second voltage dividing resistor R6 in the second switch circuit 13, and the first filter resistor R8 and the second filter resistor R9 in the control circuit 15, respectively, generate losses. Since the resistance of the second current limiting resistor R2 may be large, the loss of R2 is small, and if the dc input voltage Vin is lower than the regulated value of the first zener diode ZD1, the first switching circuit 11 may generate substantially no loss. The resistance values of the first voltage dividing resistor R5, the second voltage dividing resistor R6, the first filter resistor R8, and the second filter resistor R9 may be large, and the switching power supply 300 supplies electric power at this time, so that the first voltage dividing resistor R5, the second voltage dividing resistor R6, the first filter resistor R8, and the second filter resistor R9 are not linear losses, and are losses converted by the switching power supply 300, and the losses are relatively small. Therefore, in the case where the power management chip 200 and the switching power supply 300 are operating normally, the loss generated by the start-up circuit 100 can be greatly reduced.

It should be understood that, in the embodiment of the present application, the enhancement type switching tube Q1 and the depletion type switching tube Q2 are designed to be connected in series, so that the enhancement type switching tube Q1 and the depletion type switching tube Q2 can jointly bear the direct current input voltage Vin, so that the voltages borne by the enhancement type switching tube Q1 and the depletion type switching tube Q2 can be reduced, and the overvoltage risk is reduced. In addition, the enhancement type switching tube Q1 and the depletion type switching tube Q2 can adopt semiconductor devices with smaller voltage withstand value (the semiconductor devices with smaller voltage withstand value are low in price and more in types, more common, less high-voltage devices are available in the market and much higher in price), and the high-voltage semiconductor devices do not need to be customized, so that the cost can be reduced, and the selection is more convenient. In addition, the withstand voltage values of the enhancement type switching tube Q1 and the depletion type switching tube Q2 can have larger margins, which is favorable for widening the input voltage range of the starting circuit 100, realizing wide voltage input and high voltage input, and the risk of overvoltage of the switching device is low and the risk of overheat damage of the starting resistor 12 is low when the input voltage is high. Therefore, the circuit design is easy to implement and has a wide application range.

In the embodiment of the present application, the sum of the withstand voltage value of the depletion type switching transistor and the withstand voltage value of the enhancement type switching transistor is not smaller than the dc input voltage Vin of the dc power supply 400. For example, when the sum of the withstand voltage of the depletion switching transistor and the withstand voltage of the enhancement switching transistor is equal to Vin, the withstand voltage of the depletion switching transistor Q2 is Vo1, and the withstand voltage of the enhancement switching transistor Q1 is Vin-Vo1. When the dc input voltage Vin is constant, the higher the withstand voltage value of Q2, the lower the withstand voltage value of Q1. The higher the withstand voltage value of Q1, the lower the withstand voltage value of Q2. When the dc input voltage Vin is high, Q1 and Q2 may select semiconductor devices of lower withstand voltage values and be connected in series to commonly assume the high voltage. When the dc input voltage is high, Q1 and Q2 may select semiconductor devices of higher withstand voltage or conventional withstand voltage and be connected in series to commonly assume higher voltages.

Further, in the energy storage device 2000, a 1500V battery pack is used as the dc power supply 400, and then the enhancement type switching transistor Q1 may select a semiconductor device with a withstand voltage of 1200V, the depletion type switching transistor Q2 may select a semiconductor device with a withstand voltage of 600V, and the voltage stabilizing value of the first zener diode ZD1 may be about 450V. Obviously, the withstand voltage values of Q1 and Q2 are both conventional withstand voltage values, and the sum 1800V of the withstand voltage values of Q1 and Q2 is 300V as compared with 1500V of the battery pack voltage, so that the risk of overvoltage of Q1 and Q2 is small.

In the embodiment of the present application, since the enhanced switch Q1 is a normally closed switch, abnormal conduction of the switch Q1 in the first switch circuit 11 due to noise interference can be avoided when the dc input voltage Vin is not connected or the connected voltage does not reach the dc input voltage Vin. It can be seen that the start-up circuit 100 has a certain anti-interference capability. Since the depletion type switching tube Q2 is a normally open switch, when the starting circuit 100 is connected to the dc input voltage Vin, the power pin VCC of the power management chip 200 can be rapidly supplied with power without waiting for the depletion type switching tube Q2 to be turned on, so that the starting efficiency can be improved.

Particularly, in the battery scenario, the battery pack is used as the dc power supply 400, and when the battery pack, the switching power supply 300, and the devices (such as the energy storage device) where the power management chip 200 is located are not started, the starting circuit 100 does not consume the electric quantity of the battery pack because the enhanced switching tube Q1 is turned off. In the process of starting the power management chip 200, the starting circuit 100 can rapidly provide the starting voltage and the constant current starting current, so that the power management chip 200 has short starting time and high starting efficiency. After the power management chip 200 is started, the starting circuit 100 may automatically turn off the depletion type switching transistor Q2, so that the starting circuit 100 causes little power loss of the battery pack, contributing to the efficiency of the device. Therefore, the device can stand by with ultra-low power consumption under the condition of long-term stand-by of the device. Under the condition that the battery pack is deficient in electricity (namely, the electricity is insufficient), the electricity of the battery pack is not easy to be exhausted, and therefore the battery pack can be prevented from being damaged due to the fact that the electricity is exhausted.

It can be understood that the control circuit 15 shown in fig. 3 adopts a triode as the driving switch tube Q3, the second switch circuit 13 adopts a depletion type MOS tube as the depletion type switch tube Q2, the first connection end of the driving switch tube Q3 is connected to the second connection end of the depletion type switch tube Q2 through a voltage division voltage, the second connection end of the driving switch tube Q3 is also connected to the second connection end of the depletion type switch tube Q2, and the control end of the depletion type switch tube Q2 is connected to the voltage division voltage, so that the control voltage output by the driving switch tube Q3 can realize the turn-off of the depletion type switch tube Q2. Moreover, because the triode has a voltage amplifying function, the output control voltage can reach the turn-off threshold voltage of the MOS tube, and the triode can provide higher control current, the depletion type switching tube Q2 can be turned off rapidly based on the circuit design, the turn-off loss of the depletion type switching tube Q2 is reduced, and the loss generated by the starting resistor 12 is reduced.

Of course, in other embodiments, the enhancement type switching tube Q1 may also use an enhancement type PMOS tube or other normally-closed semiconductor switch, and implement the function of the first switching circuit 11 together with the first current limiting resistor and the voltage stabilizing circuit 111 matched with the enhancement type PMOS tube or other normally-closed semiconductor switch. The depletion type switch tube Q2 may also adopt a depletion type PMOS tube or other normally open semiconductor switch, and together with the first anti-reflection diode D2 and the voltage dividing circuit 131 matched with the depletion type PMOS tube or other normally open semiconductor switch, the function of the second switch circuit 13 is realized. The driving switch tube Q3 may also adopt other semiconductor switches (such as an enhanced MOS tube, an IGBT tube, etc.) according to actual situations, and implement the function of the control circuit 15 together with the anti-interference circuit 151 matched with the driving switch tube Q3. And are not exemplified here.

In addition, to protect the dc power supply 400 and the start-up circuit 100, a protection circuit may be further disposed between the dc power supply 400 and the first switch circuit 11. Illustratively, as shown in FIG. 3, the protection circuit includes a FUSE FUSE, an input filter capacitor Cin, and a fourth anti-reverse diode D1. The FUSE is connected in series with the positive electrode of the DC power supply 400 to provide overcurrent protection. The input filter capacitor Cin is connected between the positive and negative electrodes of the dc power supply 400, and can filter interference and reduce the fluctuation of the dc input voltage Vin. The fourth anti-reflection diode D1 is connected in series between the FUSE and the filter capacitor Cin, and the fourth anti-reflection diode D1 can perform a voltage anti-reflection function.

Referring to fig. 4, the embodiment of the application further provides a power conversion apparatus 1000.

As shown in fig. 4, the power conversion apparatus 1000 includes a start-up circuit 100, a power management chip 200, and a switching power supply 300. The start-up circuit 100 is connected to the power pin VCC of the power management chip 200, and the control pin OUT of the power management chip 200 is connected to the switching power supply 300. Specifically, the start-up circuit 100 may provide a start-up voltage and a start-up current to the power management chip 200 when the dc input voltage is connected, so that the power management chip 200 is powered on for start-up. After the power management chip 200 is started, the operation of the switching power supply 300 may be controlled, so that the switching power supply 300 generates a voltage. When the voltage generated by the switching power supply 300 reaches the voltage required by the operation of the power management chip 200, the starting circuit 100 automatically disconnects the connection with the power pin VCC, and the starting circuit 100 stops supplying power, and at this time, the switching power supply 300 continues to supply power to the power management chip 200.

The power management chip 200, the switching power supply 300 and the start-up circuit 100 may refer to the related descriptions in the embodiments shown in fig. 2 to 3, and are not repeated here.

Referring to fig. 5, the embodiment of the application further provides an energy storage device 2000.

As shown in fig. 5, the energy storage device 2000 includes a battery pack 500, a start-up circuit 100, a switching power supply 300, and a power management chip 200. The battery pack 500 is used as a direct current power supply, the battery pack 500 and a power pin of the power management chip 200 are respectively connected with the starting circuit 100, and a control pin of the power management chip 200 is connected with the switching power supply 300. The battery pack 500, the power management chip 200, the switching power supply 300, and the start-up circuit 100 may be described in the embodiments shown in fig. 2 to 4, and will not be described here again.

Finally, it should be noted that the above-mentioned embodiments are merely for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the technical solution of the present application without departing from the spirit and scope of the technical solution of the present application.

Claims

1. The starting circuit of the power management chip is characterized by comprising a first switching circuit, a starting resistor, a second switching circuit, a control circuit and a power supply circuit, wherein the control pin of the power management chip is connected to a switching power supply and used for controlling the switching power supply to work after starting,

The first switch circuit is used for being communicated when the direct current input voltage is accessed, and outputting a first output voltage;

The second switch circuit is used for outputting the first output voltage by the first switch circuit and communicating when the switch power supply does not work, and outputting a starting voltage to the power supply pin, wherein the starting voltage is used for starting the power supply management chip;

The control circuit is connected with the switching power supply and the second switching circuit, and is used for controlling the second switching circuit to be disconnected when the switching power supply works, so that the starting resistor is disconnected with the power supply pin;

The power supply circuit is connected to the power supply pin and the switching power supply, and is used for outputting a second output voltage to the power supply pin when the switching power supply works so as to supply power for the power management chip.

2. The startup circuit of claim 1, wherein the second switching circuit comprises a depletion mode switching tube, a first anti-reflection diode and a voltage divider circuit, wherein,

The first connecting end of the depletion type switching tube is connected with the cathode of the first anti-reflection diode, and the anode of the first anti-reflection diode is connected to the first switching circuit through the starting resistor;

The second connecting end of the depletion type switching tube is connected to the control circuit through the voltage dividing circuit, the control end of the depletion type switching tube is connected to the voltage dividing circuit, and the second connecting end of the depletion type switching tube is also connected to the power supply pin;

the depletion type switching tube is used for outputting the first output voltage when the first switching circuit is not operated, and is connected with the switching power supply and outputting the starting voltage to the power supply pin, and is used for switching off when the switching power supply is operated and stopping outputting the starting voltage.

3. The startup circuit of claim 2, wherein the first switching circuit comprises an enhanced switching tube, a first current limiting resistor and a voltage stabilizing circuit, wherein,

The first connecting end of the enhanced switching tube is connected with the first current limiting resistor and the voltage stabilizing circuit, the first current limiting resistor and the voltage stabilizing circuit are used for accessing direct current input voltage, the second connecting end of the enhanced switching tube is connected with the starting resistor, and the control end of the enhanced switching tube is connected with the voltage stabilizing circuit;

The enhanced switching tube is used for being conducted when the direct current input voltage is accessed, and outputting the first output voltage to the starting resistor.

4. The startup circuit of claim 3, wherein the sum of the withstand voltage of said depletion switching transistor and the withstand voltage of said enhancement switching transistor is not less than said DC input voltage.

5. The startup circuit of claim 2, wherein the depletion mode switching tube is further configured to output a constant startup current to the power supply pin when the first switching circuit outputs the first output voltage and the switching power supply is not operating.

6. The startup circuit of claim 2, wherein the control circuit comprises a drive switch, a second anti-reverse diode and an anti-tamper circuit, wherein,

The first connecting end of the driving switch tube is connected to the second switch circuit, the second connecting end of the driving switch tube is connected to the second switch circuit and the ground, the control end of the driving switch tube is connected to the second connecting end of the driving switch tube and the cathode of the second anti-reflection diode through the anti-interference circuit, and the anode of the second anti-reflection diode is connected to the switch power supply;

The driving switch tube is used for being conducted when the switching power supply works so as to be connected with the voltage dividing circuit into a loop, so that a driving voltage generated by the voltage dividing circuit is connected between the control end of the depletion type switch tube and the second connecting end of the depletion type switch tube, and the driving voltage is used for driving the depletion type switch tube to be turned off.

7. The startup circuit of claim 2, wherein the voltage divider circuit comprises a first voltage divider resistor and a second voltage divider resistor, one end of the first voltage divider resistor is connected to the second connection end of the depletion switch tube, the other end of the first voltage divider resistor is connected to the control end of the depletion switch tube, and the second voltage divider resistor is connected to the control circuit.

8. The startup circuit of claim 1, wherein the power supply circuit comprises a rectifying circuit and a third anti-reverse diode, the rectifying circuit connected between an anode of the third anti-reverse diode and the switching power supply, a cathode of the third anti-reverse diode connected to the power supply pin.

9. A power conversion device, characterized in that the power conversion device comprises a switching power supply, a power management chip and a start-up circuit according to any of claims 1 to 8, the start-up circuit being connected to a power supply pin of the power management chip, a control pin of the power management chip being connected to the switching power supply.

10. An energy storage device, characterized in that the energy storage device comprises a battery pack, a switching power supply, a power management chip and the starting circuit according to any one of claims 1 to 8, wherein power pins of the battery pack and the power management chip are respectively connected with the starting circuit, and a control pin of the power management chip is connected with the switching power supply.