TWI663824B - Power conversion device - Google Patents

Abstract

A power conversion device includes a conversion circuit, a switching circuit, an energy storage element, and a detection circuit. The conversion circuit includes a transformer, an output capacitor, and an output terminal. The primary side of the transformer receives the input voltage, and the output capacitor is electrically connected between the output terminal and the ground terminal. The switching circuit and the energy storage element are connected in series between the output terminal and the ground terminal. When the input voltage is supplied, the conversion circuit converts the input voltage and generates a power supply voltage through the output capacitor, and the detection circuit does not conduct the switching circuit and charges the energy storage element. When the input voltage is not supplied, the detection circuit turns on the switching circuit, and the output capacitor and the power supply voltage of the energy storage element provide a hold time.

Description

Power conversion device

The present invention relates to a power conversion technology, and more particularly, to a power conversion device.

Generally speaking, electronic equipment is provided with a power conversion device to supply a stable power supply voltage. In addition, when the power conversion device is suddenly powered off, the power conversion device can continuously output the power supply voltage for a hold-up time to avoid the impact of the instant power failure on the electronic equipment. However, under high temperature for a long time, the energy stored in the output capacitor of the power conversion device also decreases. As the stored energy of the output capacitor is reduced, the holding time of the power conversion device is correspondingly shortened. Therefore, the conventional power conversion device often has a problem of insufficient holding time, thereby reducing the stability of the electronic equipment.

The invention provides a power conversion device, which can improve the problem of insufficient maintenance time.

The power conversion device of the present invention includes a conversion circuit, a switching circuit, and a storage circuit. Functional components and detection circuits. The conversion circuit includes a transformer, an output capacitor, and an output terminal. The primary side of the transformer receives the input voltage, and the output capacitor is electrically connected between the output terminal and the ground terminal. The switching circuit and the energy storage element are connected in series between the output terminal and the ground terminal. The detection circuit is electrically connected to the secondary side of the transformer, the switching circuit and the energy storage element. When the input voltage is supplied, the conversion circuit converts the input voltage and generates a power supply voltage through the output capacitor, and the detection circuit does not conduct the switching circuit and charges the energy storage element. When the input voltage is not supplied, the detection circuit turns on the switching circuit, and the output capacitor and the energy storage element supply the power voltage during the maintenance time.

In an embodiment of the present invention, the conversion circuit further includes a first switch, a first diode, and a first resistor. The first switch is electrically connected to the primary side of the transformer. The anode of the first diode is electrically connected to the secondary side of the transformer. The first resistor is electrically connected between the cathode of the first diode and the output terminal.

In an embodiment of the present invention, the switching circuit includes a second diode and a second switch. The cathode of the second diode is electrically connected to the output terminal. The second switch is electrically connected between the anode of the second diode and the energy storage element.

Based on the above, the power conversion device of the present invention can charge the energy storage element when an input voltage is supplied. In addition, when the input voltage is not supplied, the power conversion device can supply the power voltage through the output capacitor and the energy storage element. Thereby, the maintenance time of the power conversion device can be extended.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

100, 200‧‧‧ power conversion device

110‧‧‧ conversion circuit

111‧‧‧input

112‧‧‧output

SW1‧‧‧The first switch

T1‧‧‧Transformer

D1‧‧‧First Diode

R1‧‧‧first resistor

C1‧‧‧ output capacitor

S1‧‧‧Control signal

120, 220‧‧‧switching circuit

D2‧‧‧Second Diode

SW2‧‧‧Second switch

130‧‧‧energy storage element

C2‧‧‧ auxiliary capacitor

140, 240‧‧‧ detection circuit

141‧‧‧ Comparator

D3‧‧‧ third diode

VI‧‧‧Input voltage

VO‧‧‧ Power supply voltage

101‧‧‧load

241‧‧‧amplification circuit

R2‧‧‧Second resistor

R3‧‧‧Third resistor

FIG. 1 is a schematic diagram of a power conversion device according to an embodiment of the invention.

FIG. 2 is a schematic diagram of a power conversion device according to another embodiment of the present invention.

FIG. 1 is a schematic diagram of a power conversion device according to an embodiment of the invention. As shown in FIG. 1, the power conversion device 100 includes a conversion circuit 110, a switching circuit 120, an energy storage element 130, and a detection circuit 140. The conversion circuit 110 has an input terminal 111 and an output terminal 112, and includes a transformer T1 and an output capacitor C1. The primary side of the transformer T1 is electrically connected to the input terminal 111 of the conversion circuit 110 to receive the input voltage VI. The output capacitor C1 is electrically connected between the output terminal 112 and the ground terminal of the conversion circuit 110 and can be used to generate a power supply voltage VO.

The switching circuit 120 and the energy storage element 130 are connected in series between the output terminal 112 and the ground terminal of the conversion circuit 110. The detection circuit 140 is electrically connected to the secondary side of the transformer T1, the switching circuit 120, and the energy storage element 130. In operation, when the input voltage VI is supplied, that is, when the conversion circuit 110 can receive the input voltage VI, the conversion circuit 110 can convert the input voltage VI and generate the power supply voltage VO through the output capacitor C1, and the detection circuit 140 The switching circuit 120 may not be turned on and the energy storage element 130 may be charged. When the input voltage VI is not supplied, that is, when the conversion circuit 110 cannot receive the input voltage VI, the detection circuit 140 can turn on the switching circuit 120, and the output capacitor C1 and the energy storage element 130 can be held-up time) supply voltage VO.

In other words, when an external power source normally supplies power to the power conversion device 100, the power conversion device 100 may store energy in the energy storage element 130 in advance. When the power conversion device 100 is suddenly powered off, the power conversion device 100 can continuously provide the power supply voltage VO through the output capacitor C1 and the energy storage element 130 for a maintenance time. It is worth mentioning that the existing power conversion device can only continuously output the power supply voltage by using the output capacitor when the power is turned off. Therefore, compared with the existing power conversion device, the power conversion device 100 can use the energy stored in the energy storage element 130 in advance to effectively extend the maintenance time, thereby helping to improve the performance of electronic equipment provided with the power conversion device 100. stability.

Please continue to refer to FIG. 1, the conversion circuit 110 may be, for example, a flyback converter, and the conversion circuit 110 further includes a first switch SW1, a first diode D1, and a first resistor R1. The first switch SW1 is electrically connected to the primary side of the transformer T1. The anode of the first diode D1 is electrically connected to the secondary side of the transformer T1. The first resistor R1 is electrically connected between the cathode of the first diode D1 and the output terminal 112 of the conversion circuit 110. The first switch SW1 is controlled by the control signal S1 to be switched to a conductive or non-conductive state. As the state of the first switch SW1 changes, the current flowing through the transformer T1 will be relatively changed, thereby causing the output capacitor C1 to be charged and discharged. Thereby, the conversion circuit 110 can convert the input voltage VI into the power supply voltage VO in response to the switching of the first switch SW1.

The switching circuit 120 includes a second diode D2 and a second switch SW2. The cathode of the second diode D2 is electrically connected to the output terminal 112 of the conversion circuit 110. The second switch SW2 is electrically connected between the anode of the second diode D2 and the energy storage element 130. The detection circuit 140 includes a comparator 141 and a third diode D3. The inverting input terminal of the comparator 141 is electrically connected to the first terminal of the first resistor R1 and the cathode of the first diode D1, and the non-inverting input terminal of the comparator 141 is electrically connected to the second terminal of the first resistor R1. The output terminal of the comparator 141 is electrically connected to the control terminal of the second switch SW2. The anode of the third diode D3 is electrically connected to the secondary side of the transformer T1, and the cathode of the third diode D3 is electrically connected to the energy storage element 130. In addition, the energy storage element 130 may be composed of an auxiliary capacitor C2. The first terminal of the auxiliary capacitor C2 is electrically connected to the cathode of the second switch SW2 and the third diode D3, and the second terminal of the auxiliary capacitor C2 is electrically connected to the ground terminal.

In operation, when the input voltage VI is supplied to the conversion circuit 110 and the conversion circuit 110 turns on the first switch SW1 according to the control signal S1, the first diode D1 is in a reverse bias and is not turned on, and the output capacitor C1 is connected to the load 101 is discharged. In addition, the switching circuit 120 and the detection circuit 140 stop operating.

When the input voltage VI is supplied to the conversion circuit 110 and the conversion circuit 110 does not turn on the first switch SW1 according to the control signal S1, the first diode D1 is turned on in a forward bias voltage, thereby causing the secondary side of the transformer T1 The current can charge the output capacitor C1 and provide energy to the load 101. In addition, the third diode D3 is turned on under a forward bias, thereby causing the detection circuit 140 to charge the energy storage element 130 (for example, the auxiliary capacitor C2). Furthermore, the voltage at the non-inverting input terminal of the comparator 141 is smaller than the voltage at its inverting input terminal. Therefore, the comparator 141 can generate a low level voltage, and thus the second switch SW2 cannot be turned on. In other words, when the input voltage VI is supplied and the first When one switch SW1 is not turned on, the detection circuit 140 does not turn on the second switch SW2 and can charge the energy storage element 130.

When the input voltage VI stops being supplied to the conversion circuit 110, that is, when the power conversion device 100 is suddenly powered off, the residual energy stored in the transformer T1 and the parasitic capacitance in the conversion circuit 110 may cause the inverting input terminal of the comparator 141 Maintained at a lower voltage level. At this time, the voltage at the non-inverting input terminal of the comparator 141 will be greater than the voltage at its inverting input terminal, so the comparator 141 can generate a high-level voltage, and then the second switch SW2 can be turned on. In other words, when the input voltage VI is not supplied, the detection circuit 140 may turn on the second switch SW2 during the sustaining time. As the second switch SW2 is turned on, the energy stored in the energy storage element 130 can be transmitted to the load 101 through the second switch SW2 and the second diode D2. Thereby, during the maintaining time after the power conversion device 100 is powered off, the output capacitor C1 and the energy storage element 130 will continuously supply the power supply voltage VO to the load 101.

FIG. 2 is a schematic diagram of a power conversion device according to another embodiment of the present invention. Compared with the embodiment of FIG. 1, the switching circuit 220 in the power conversion device 200 of FIG. 2 further includes a second resistor R2, and the detection circuit 240 in the power conversion device 200 further includes an amplifier circuit 241 and a third resistor R3 .

Specifically, the second resistor R2 and the second diode D2 are connected in series between the output terminal 112 of the conversion circuit 110 and the second switch SW2, so as to reduce the current flowing through the second diode D2. The amplifier circuit 241 is electrically connected between the output terminal of the comparator 141 and the control terminal of the second switch SW2, so as to amplify the output voltage of the comparator 141. The third resistor R3 is electrically connected to the control circuit of the amplifier circuit 241 and the second switch SW2. Control terminals to reduce the current transmitted to the control terminal of the second switch SW2.

Similar to the embodiment of FIG. 1, when the input voltage VI is supplied and the first switch SW1 is turned on, the output capacitor C1 can discharge the load 101, and the switching circuit 220 and the detection circuit 240 stop operating. When the input voltage VI is supplied and the first switch SW1 is not turned on, the output capacitor C1 and the energy storage element 130 can be charged, and the detection circuit 240 does not turn on the second switch SW2 in the switching circuit 220. When the input voltage VI is not supplied, the comparator 141 can generate a high-level voltage, and the amplifier circuit 241 can amplify the high-level voltage. In addition, the amplified high-level voltage can be transmitted to the control terminal of the second switch SW2 through the third resistor R3 to thereby turn on the second switch SW2. In addition, as the second switch SW2 is turned on, the energy stored in the energy storage element 130 can be transmitted to the load 101 through the second switch SW2, the second diode D2, and the second resistor R2. Thereby, the output capacitor C1 and the energy storage element 130 will continuously supply the power supply voltage VO to the load 101 during the sustaining time after the power conversion device 200 is powered off. As for the detailed configuration and operation of each element in the embodiment of FIG. 2, it is included in the embodiment of FIG. 1, so it will not be repeated here.

In summary, the power conversion device of the present invention can charge the energy storage element when the input voltage is supplied, and the power conversion device can supply the output capacitor and the energy storage element during the maintenance time when the input voltage is not supplied. voltage. In other words, the power conversion device can store energy in the energy storage element in advance. Therefore, when the power conversion device is suddenly powered off, the power conversion device can use the energy stored in the energy storage element to extend the maintenance time effectively, thereby helping to improve the stability of the electronic equipment provided with the power conversion device.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims (10)

A power conversion device includes: a conversion circuit including a transformer, an output capacitor, and an output terminal, wherein a primary side of the transformer receives an input voltage, and the output capacitor is electrically connected between the output terminal and a ground terminal; A switching circuit and an energy storage element connected in series between the output terminal and the ground terminal; and a detection circuit electrically connecting the secondary side of the transformer, the switching circuit and the energy storage element, wherein when When the input voltage is supplied, the conversion circuit converts the input voltage and generates a power voltage through the output capacitor, and the detection circuit does not turn on the switching circuit and charges the energy storage element. When the input voltage is not supplied, At this time, the detection circuit turns on the switching circuit, and the output capacitor and the energy storage element supply the power voltage within a sustaining time. The power conversion device according to item 1 of the scope of patent application, wherein the conversion circuit further includes: a first switch electrically connected to the primary side of the transformer; a first diode whose anode is electrically connected to the transformer The secondary side; and a first resistor electrically connected between the cathode of the first diode and the output terminal. The power conversion device according to item 2 of the scope of patent application, wherein the switching circuit includes: a second diode, a cathode of which is electrically connected to the output terminal; and a second switch, which is electrically connected to the second two Between the anode of the pole body and the energy storage element. According to the third aspect of the patent application scope, the switching circuit further includes a second resistor, and the second resistor and the second diode are connected in series between the output terminal and the second switch. The power conversion device according to item 3 of the scope of patent application, wherein when the input voltage is supplied and the first switch is turned on, the detection circuit stops operating, when the input voltage is supplied and the first switch is not When conducting, the detection circuit does not conduct the second switch and charges the energy storage element, and when the input voltage is not supplied, the detection circuit turns on the second switch during the sustaining time. The power conversion device according to item 3 of the scope of patent application, wherein the detection circuit includes: a comparator, an inverting input terminal thereof is electrically connected to the first terminal of the first resistor, and a non-inverting input terminal of the comparator The second terminal of the first resistor is electrically connected, the output terminal of the comparator is electrically connected to the second switch; and a third diode whose anode is electrically connected to the secondary side of the transformer, the third two The cathode of the pole body is electrically connected to the energy storage element. The power conversion device according to item 6 of the patent application, wherein the detection circuit further includes an amplifier circuit, and the amplifier circuit is electrically connected between the comparator output terminal and the second switch. The power conversion device according to item 7 of the scope of patent application, wherein the detection circuit further includes a third resistor, and the third resistor is electrically connected between the amplifier circuit and the second switch. The power conversion device according to item 6 of the scope of patent application, wherein the energy storage element includes an auxiliary capacitor, and a first end of the auxiliary capacitor is electrically connected to the cathode of the second switch and the third diode, the The second terminal of the auxiliary capacitor is electrically connected to the ground terminal. The power conversion device according to item 1 of the patent application scope, wherein the conversion circuit is a flyback converter.