TWI440294B - Standby power efficiency improved ac to dc power converter device - Google Patents

Description

AC/DC power conversion device capable of improving standby power efficiency

The invention relates to a power conversion device, in particular to an AC/DC power conversion device.

With the increasing popularity of smart electronic devices, such as smart home appliances, the use of standby power has become a focus of attention. Standby power is when the electronic device is in a standby mode (held in a waiting state), such as maintaining settings. The power required for the operation mode, the reduction of the heat engine time, or the standby of the remote command, the voltage of which is different from the main voltage used by the electronic device to operate in the normal mode, and is usually small, and therefore needs to be generated separately.

Referring to FIG. 1 and FIG. 2, it is a conventional off-line AC/DC power converter 1 commonly used in an electronic device, which mainly includes an AC/DC conversion circuit 11, a DC-DC converter circuit 12, and a standby power. The conversion circuit 13 and a pulse width modulation (PWM) signal generator 14. The AC/DC conversion circuit 11 converts an AC input voltage (90~264 V _ac ) into a DC bus voltage V _BUS (380 V), and then performs a step-down conversion of the DC bus voltage V _BUS through the DC buck conversion circuit 12 to A main voltage V _{DC is} output. The standby power conversion circuit 13 performs step-down conversion on the DC bus voltage V _BUS to output a standby voltage Vsb, and the pulse width modulation (PWM) signal generator 14 generates two pulse width modulation signals which are mutually inverted to be respectively controlled. The first switch SW1 and the second switch SW2 of the DC step-down conversion circuit 12 are alternately switched. When the electronic device operates in the normal mode, the DC step-down conversion circuit 12 supplies the main voltage V _DC to the electronic device, and when the electronic device operates in the standby mode, the standby power conversion circuit 13 supplies the standby voltage Vsb to the electronic device.

However, when the main mode V _DC and the standby voltage Vsb need to be simultaneously supplied to the electronic device in the normal mode, since the load in the normal mode is heavier than the standby mode, the standby power conversion circuit 13 is a conventional isolated flyback conversion circuit. The purpose is to receive the DC bus voltage and provide the standby voltage Vsb. This circuit is in the high input/output voltage difference mode. In the case of heavy load and large output current, the transformer leakage inductance and distributed capacitance (spur or parasitic) The presence of components) causes voltage and current surges to increase, resulting in loss of conversion efficiency, and this phenomenon will become more pronounced as the load increases, resulting in a heavier load and a lower conversion efficiency, which greatly reduces the reliability of the power supply.

Accordingly, an object of the present invention is to provide an AC/DC power conversion apparatus capable of improving standby power efficiency while improving power conversion efficiency and power supply reliability.

In order to achieve the above object, the present invention can improve the standby power efficiency of the AC/DC power conversion device, including an AC/DC conversion circuit, a DC-down conversion circuit, a first standby power conversion circuit, and a second standby power conversion circuit.

The AC/DC conversion circuit receives an AC power and performs DC conversion to output a DC bus voltage; the DC buck conversion circuit receives the DC bus voltage and performs step-down conversion to output a main power voltage; The first standby power conversion circuit receives the main power supply voltage via a first switch, and performs pulse width modulation control on the first switch, and the first standby power conversion circuit performs step-down conversion on the main power supply voltage and outputs one a first standby voltage; the second standby power conversion circuit receives the DC bus voltage input via a second switch, and performs pulse width modulation control on the second switch, the second standby power conversion circuit will be the DC bus The voltage is stepped down to output a second standby voltage.

Preferably, the AC/DC power conversion device further includes a controller for controlling whether the first switch and the second switch are turned on or not. When the DC buck conversion circuit operates, the controller controls the second switch to be non-conductive. And performing pulse width modulation control on the first switch. When the DC buck conversion circuit stops operating, the controller controls the first switch to be non-conducting, and performs pulse width modulation control on the second switch.

Preferably, the DC step-down conversion circuit and the first standby power conversion circuit operate in a normal mode, and the second standby power conversion circuit operates in a standby mode.

Preferably, the first standby power conversion circuit is a step-down DC-DC power conversion circuit, and further includes an inductor, a diode, and a capacitor and a resistor connected in parallel, the inductor and the first switch The other end is electrically coupled to the capacitor and the one end of the resistor, and the other end of the first switch is electrically coupled to the DC step-down conversion circuit, and the diode is electrically coupled to the inductor in reverse The first standby power conversion circuit is a flyback DC-to-DC power conversion circuit, and includes a transformer, the diode, the capacitor, and the resistor Wherein the primary side coil of the transformer receives the DC bus voltage input, the other end is electrically coupled to one end of the second switch, the other end of the second switch is grounded, and the secondary side coil of the transformer is in the A standby power conversion circuit is used as an inductor when operating.

Preferably, the first switch is a low voltage MOSFET switch and the second switch is a high voltage MOSFET switch.

Preferably, the DC step-down conversion circuit is a half-bridge LLC resonant power conversion circuit including a third switch and a fourth switch connected in series, and the AC/DC power conversion device further includes a pulse width modulation signal generator. And generating two mutually inverting pulse width modulation signals to control the third switch and the fourth switch of the DC buck conversion circuit.

One of the functions of the present invention is to integrate the first standby power conversion circuit and the second standby power conversion circuit, let the first standby power conversion circuit share the partial circuit with the second standby power conversion circuit, and let the first standby power conversion The circuit directly uses the secondary side coil of the transformer of the second standby power conversion circuit as the inductance of the filter circuit thereof, without additionally providing an inductor to reduce the circuit manufacturing cost, and in the normal mode, using the first standby power The first standby voltage provided by the conversion circuit increases the conversion efficiency, and in the standby mode, the second standby voltage output by the second standby power conversion circuit is used, thereby improving the overall standby power efficiency and improving the reliability of the power supply. The efficacy and purpose of the present invention are indeed achieved.

The foregoing and other objects, features, and advantages of the invention are set forth in the <RTIgt;

The AC/DC power conversion device capable of improving standby power efficiency can be widely applied to an external adapter, a desktop power supply, a servo power supply, or various power supply products requiring standby power.

As shown in FIG. 3 and FIG. 4, a preferred embodiment of the AC/DC power conversion device 2 for improving standby power efficiency includes an AC/DC conversion circuit 21, a DC-to-Buck conversion circuit 22, and a first standby power. The conversion circuit 23, a second standby power conversion circuit 24, a pulse modulation signal generator 25 and a controller 26.

The AC/DC conversion circuit 21 receives an AC voltage (90~264Vac) input and DC-converts it to output a DC bus voltage V _BUS (for example, 380V). The AC-DC conversion circuit 21 mainly includes a full-wave rectifier 211 and a power. The factor corrector 212, the full-wave rectifier 211 (for example, a bridge rectifier) performs full-wave rectification on the AC voltage, and then outputs the power to the power factor corrector 212. The power factor corrector 212 is mainly composed of an inductor, a diode, and a transistor, and The full-wave rectified voltage output from the full-wave rectifier 211 is subjected to power factor correction and voltage regulation to generate a DC bus voltage V _BUS .

The DC step-down conversion circuit 22 is electrically coupled to the AC/DC conversion circuit 21. In the present embodiment, the DC step-down conversion circuit 22 is an isolated resonant converter, such as a conventional LLC resonant converter, which is based on a terminal load. Demand, step-down conversion of the DC bus voltage V _BUS to output a main power voltage V _DC (usually 12V or 19V), and the main power supply voltage V _DC is usually the main power required for the load terminal to operate in a normal mode. .

The first standby power conversion circuit 23 is electrically coupled to the DC step-down conversion circuit 22 and receives the main power voltage V _DC via a first switch SW1, thereby performing pulse width modulation control on the first switch SW1. The first standby power conversion circuit 23 performs step-down conversion of the main power supply voltage V _DC and outputs a first standby voltage Vsb1 (usually 5V or 12V); more specifically, the first standby power conversion circuit 23 is a The buck DC-DC power conversion circuit includes an inductor element L, a diode D, and a capacitor Co and a load resistor Ro in parallel, and an inductor element L, in addition to the first switch SW1. One end is electrically coupled to one end of the first switch SW1, the other end is electrically coupled to one end of the capacitor Co and the load resistor Ro, and the other end of the first switch SW1 is electrically coupled to the DC step-down conversion circuit 22, the diode D ( The flywheel diode is electrically coupled between the inductor element L and one end of the first switch SW1 and the other end of the capacitor Co, and the first switch SW1 is a low voltage MOSFET switch; by performing the first switch SW1 Pulse width modulation control to make high frequency according to pulse width Switching the diode D V _DC voltage of the main power supply is switched to a high frequency pulsating DC primary power supply voltage V _DC and the zero of the two states, and then after the inductance L and the capacitance Co was low pass filter, generating The first standby voltage Vsb1 is lower than the voltage of the main power supply voltage V _DC .

And since the first standby power conversion circuit 23 converts the main power supply voltage VDC into the first standby DC voltage Vsb1, which is a low voltage difference conversion operation, the conversion efficiency is high, and is suitable for a normal mode that is applied at a high load and requires a relatively large current output. Next, therefore, the first standby voltage Vsb1 is mainly used as the standby power source required in the normal mode.

The second standby power conversion circuit 24 is electrically coupled to the AC/DC conversion circuit 21, and receives a DC bus voltage V _BUS (380V) input via a second switch SW2, thereby performing pulse width modulation control on the second switch SW2. The second standby power conversion circuit 24 steps down the DC bus voltage V _BUS and outputs a second standby voltage Vsb2 (usually 5V or 12V). More specifically, the second standby power conversion circuit 24 is an isolated buck-boost converter, such as a conventional flyback DC-to-DC power conversion circuit, except for the second switch SW2. The utility model further includes a transformer 241, and shares a diode D, a capacitor Co and a load resistor Ro with the first standby power conversion circuit 23, wherein one end of the primary side coil 242 of the transformer 241 receives the DC bus voltage V _BUS input, and the other end is One end of the second switch SW1 is electrically coupled, the other end of the second switch SW1 is grounded, and the second switch SW2 is a high voltage MOSFET switch; in particular, the secondary side coil 243 of the transformer 241 is provided by the second standby power conversion circuit 24 It is used for the inductor L, so there is no need to set an additional inductor. Thereby, the second switch SW2 is subjected to pulse width modulation control so as to be switched at a high frequency according to the pulse width, and the transformer 241 is controlled to perform step-down conversion, and then low-pass filtered by the inductor L and the capacitor Co to generate a comparison. The second standby voltage Vsb2 at which the voltage of the main power supply voltage V _DC is low.

Moreover, if the second standby power conversion circuit 24 is operated in the normal mode of high load (high current output), it belongs to the high voltage difference conversion operation, and the leakage inductance and distributed capacitance of the transformer 241 cause the voltage and current to oscillate. Large, affecting the conversion efficiency, therefore, the second standby DC voltage Vsb2 is mainly used as a low-load and low-current output standby mode, and does not need to output the standby power supply when the main power supply voltage V _DC .

In addition, the pulse modulation signal generator 25 is mainly configured to respectively generate two pulse width modulation signals which are mutually inverted to respectively control a third switch SW3 and a fourth switch SW4 of the DC step-down conversion circuit 22 to be alternately controlled. Switching on to perform a buck conversion action.

Moreover, since the first standby power conversion circuit 23 and the second standby power conversion circuit 24 share part of the circuit, only one operation can be performed at a time, and the first standby power conversion circuit 23 and the second standby power conversion circuit 24 are respectively operated normally. Mode and standby mode. Therefore, the controller 26 is used to control whether the first standby power conversion circuit 23 and the second standby power conversion circuit 24 operate or not. More specifically, the controller 26 is electrically coupled to the first switch SW1 of the first standby power conversion circuit 23 and the second switch SW2 of the second standby power conversion circuit 24. When the AC/DC power conversion device 2 operates in the normal mode and needs to simultaneously output the main power voltage VDC and the first standby voltage Vsb1 to the load terminal, the controller 26 disables the second switch SW2 and outputs a pulse width modulation signal. Performing pulse width modulation control on the first switch SW1 to enable the first standby power conversion circuit 23 to output the first standby voltage Vsb1; and when the AC/DC power conversion device 2 is operating in the standby mode, only the second standby voltage Vsb1 is required to be supplied At the load end, the controller 26 disables the first switch, and outputs another pulse width modulation signal to perform pulse width modulation control on the second switch SW2, so that the second standby power conversion circuit 24 can output the second standby voltage Vsb2. To the load terminal, the standby power generated by the different standby power conversion circuits can be used to improve the conversion efficiency of the overall standby power in response to different operating modes.

In summary, the above embodiment integrates the first standby power conversion circuit 23 and the second standby power conversion circuit 24, and allows the first standby power conversion circuit 23 and the second standby power conversion circuit 24 to share a part of the circuit, and let The first standby power conversion circuit 23 directly uses the secondary side coil of the transformer 241 of the second standby power conversion circuit 24 as the inductance L of its filter circuit, without additionally providing an inductor, reducing the circuit manufacturing cost; and in normal In the mode, the first standby voltage Vsb1 provided by the first standby power conversion circuit 23 having high conversion efficiency and relatively large current output capability can improve the conversion efficiency of the conventional standby power conversion circuit 13 in the normal mode. Problem, and in a standby mode in which it is not necessary to output the main power supply voltage VDC (ie, no main power supply voltage VDC output), the second standby power conversion circuit 24 outputs the second standby voltage Vsb2, thereby improving the overall standby power efficiency, and Improving the reliability of the power supply does achieve the efficacy and purpose of the present invention.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2‧‧‧AC and DC power conversion device

21‧‧‧ AC and DC conversion circuit

22‧‧‧DC buck converter circuit

23‧‧‧First standby power conversion circuit

24‧‧‧Second standby power conversion circuit

25‧‧‧ Pulse width modulation signal generator

26‧‧‧ Controller

211‧‧‧Full-wave rectifier

212‧‧‧Power Factor Corrector

241‧‧‧Transformer

242‧‧‧ primary side coil

243‧‧‧second side coil

V _BUS ‧‧‧ DC bus voltage

V _DC ‧‧‧main power supply voltage

Vsb1‧‧‧First standby voltage

Vsb2‧‧‧second standby voltage

1 is a circuit block diagram of a conventional AC/DC power converter;

2 is a schematic circuit diagram of the AC/DC power converter of FIG. 1;

3 is a circuit block diagram of a preferred embodiment of an AC/DC power conversion device capable of improving standby power efficiency according to the present invention; and

4 is a schematic diagram showing a detailed circuit of an AC/DC power conversion device capable of improving standby power efficiency in the embodiment.

2. . . AC/DC power conversion device

twenty one. . . AC/DC converter circuit

twenty two. . . DC step-down conversion circuit

twenty three. . . First standby power conversion circuit

twenty four. . . Second standby power conversion circuit

25. . . Pulse width modulation signal generator

26. . . Controller

V _BUS . . . DC bus voltage

V _DC . . . Mains voltage

Vsb1. . . First standby voltage

Vsb2. . . Second standby voltage

Claims (5)

An AC/DC power conversion device capable of improving standby power efficiency, comprising: an AC/DC conversion circuit, receiving an AC power and performing DC conversion to output a DC bus voltage; and a DC-to-Buck conversion circuit to receive the DC current And discharging the voltage and outputting a main power supply voltage; a first standby power conversion circuit receiving the main power supply voltage via a first switch, and performing pulse width modulation control on the first switch, the first The standby power conversion circuit performs step-down conversion on the main power supply voltage and outputs a first standby DC voltage; a second standby power conversion circuit receives the DC bus voltage input via a second switch, and performs the second switch a pulse width modulation control, the second standby power conversion circuit performs a step-down conversion of the DC bus voltage to output a second standby DC voltage; and a controller that controls whether the first switch and the second switch are turned on or not When the DC step-down conversion circuit operates, the controller controls the second switch to be non-conducting, and performs pulse width adjustment on the first switch. Control, when the DC buck converter circuit to stop operating, the controller controls the first switch is non-conductive, and the PWM control of the second switch. An AC/DC power conversion device capable of improving standby power efficiency according to the first aspect of the patent application, wherein the DC step-down conversion circuit and the first standby power conversion circuit operate at a high load and require a relatively large current output. The normal mode, and the second standby power conversion circuit is a standby mode that operates at a low load and requires only low current output. The AC/DC power conversion device capable of improving standby power efficiency according to the first aspect of the patent application, wherein the first standby power conversion circuit is a step-down DC-DC power conversion circuit, and further includes an inductor, one or two a pole and a parallel capacitor and a load resistor, the inductor is electrically coupled to one end of the first switch, the other end is electrically coupled to the capacitor and the load resistor, and the other end of the first switch is coupled to the DC The step-down conversion circuit is electrically coupled, the diode is electrically coupled between the inductor and one end of the first switch and the other end of the capacitor; the second standby power conversion circuit is a flyback DC The DC power conversion circuit includes a transformer and the diode, the capacitor and the load resistor, wherein one end of the primary side coil of the transformer receives the DC voltage input, and the other end is electrically coupled to one end of the second switch, The other end of the second switch is grounded, and the secondary side coil of the transformer is the inductor. The AC/DC power conversion device according to any one of claims 1 to 3, wherein the first switch is a low voltage MOSFET switch, and the second switch is a high voltage MOSFET switch. An AC/DC power conversion device capable of improving standby power efficiency according to claim 4, wherein the DC buck conversion circuit is a half bridge LLC resonant power conversion including a third switch and a fourth switch connected in series a circuit, and the AC/DC power conversion device further includes a pulse width modulation signal generator for generating two mutually inverting pulse width modulation signals to control the third switch of the DC buck conversion circuit and the The fourth switch.