TWI558076B - Ac/dc power supply circuit and method thereof - Google Patents

Description

AC/DC power supply circuit and method thereof

The invention relates to an AC/DC power supply circuit and a method thereof, in particular to an AC/DC power supply circuit and a method thereof which can be used for both alternating current and direct current.

Previously, in order to supply electric power to various electric appliances in a general household, an AC power distribution system centered on a commercial power source was used. In recent years, DC distributed power sources using solar cells (for example, photovoltaic power generation), fuel cells, or batteries for general household use have become popular. Further, in order to reduce the power loss when the AC power in the respective electric equipment is converted into the DC power, it is also recommended to introduce the DC power distribution system for the home. In this case, in addition to the previous AC power distribution system, it is also necessary to set the DC power distribution system at the same time.

Therefore, electrical equipment or electrical appliances suitable for both AC and DC have also flourished. However, in general, both AC and DC electrical equipment are modulated by full-wave rectification. For example, electrical equipment for both AC and DC is output to the back-end circuit through a rectifier circuit. When the DC power passes through the rectifier circuit, the loss of the diode on the rectifier circuit causes burn and power consumption, thereby affecting the efficiency of the output of the back-end circuit. Even the diode on the rectifier circuit is damaged by the heat and power consumption.

The invention provides an AC/DC power supply circuit for distinguishing AC/DC power supply and avoiding power loss of the rectifier circuit, thereby improving the output power of the circuit.

The invention provides an AC/DC power supply circuit, which is electrically connected to an alternating current or a continuous current through a pair of input terminals, and the AC/DC power supply circuit is electrically connected to have a An isolated power conversion circuit of the rectifier circuit, the AC/DC power supply circuit comprises: an optocoupler conversion unit, a trigger unit, a logic unit and a switching unit. The trigger unit is coupled to the optocoupler conversion unit. The logic unit is coupled to the contact unit. The switching unit is coupled to the logic unit. Wherein, when the optocoupler conversion unit receives the alternating current via the pair of input terminals, the optocoupler conversion unit outputs a first pulse signal to the trigger unit, and the trigger unit outputs a second pulse signal according to the first pulse signal. The logic unit sends a first signal to the switching unit according to the second pulse signal, and the switching unit is in a first state according to the first signal. When the optocoupler conversion unit receives the DC power through the pair of input terminals, the trigger unit outputs a logic signal to the logic unit, and the logic unit outputs a second signal that is delayed by a preset time according to the logic signal to the switching unit. The switching unit is in a second state according to the second signal.

The invention provides a method for selecting an AC/DC power supply path, which is suitable for electrically connecting an alternating current or a continuous current through a pair of input terminals, and an AC/DC power supply circuit is electrically connected to an isolated power conversion circuit having a rectifier circuit. The DC power supply selection method includes: determining whether an optocoupler conversion unit receives an alternating current, and if the determination result is yes, the optocoupler conversion unit outputs a first pulse signal to the trigger unit, and the trigger unit is configured according to the first pulse signal. And outputting a second pulse signal to the logic unit; the logic unit outputs a first signal to the switching unit according to the second pulse signal, and the switching unit is in a first state according to the first signal; if the determination result is no, The trigger unit outputs a logic signal to the logic unit; the logic unit outputs a second signal delayed by a predetermined time according to the logic signal to the switching unit, and the switching unit is in a second state according to the second signal.

The AC/DC power supply circuit of the present invention transmits an AC or DC power through an optocoupler conversion unit. The optocoupler conversion unit generates a first pulse signal according to the AC power to the trigger unit, so the trigger unit will continuously trigger the logic unit. Therefore, the logic unit is also continuously triggered and delayed, whereby the logic unit controls the switching unit to be in a switching state of an alternating current through the rectifier circuit. In addition, the optocoupler conversion unit is turned off according to the direct communication, so the trigger unit triggers the logic unit. So the output of the logic unit The signal is delayed after a predetermined time, whereby the logic unit controls the switching unit to be in a switching state in which the current is directly bypassed by the rectifier circuit and coupled to the back circuit. It can be seen from this that the present embodiment does achieve the output power of the boost circuit.

The above summary and the following examples are intended to be illustrative of the invention and the embodiments of the invention.

1‧‧‧AC power supply circuit

8‧‧‧ Back-end circuit

9‧‧‧Rectifier circuit

10‧‧‧optical coupling unit

12‧‧‧Trigger unit

14‧‧‧Logical unit

16‧‧‧Switch unit

160‧‧‧Relay

VCC‧‧‧ working voltage source

C1, C2‧‧‧ capacitor

D0‧‧‧ bypass path

D1‧‧‧ diode

Q1‧‧‧Optoelectronics

I1, I2‧‧‧ input

O1, RST‧‧‧ output

L1, L2‧‧‧ input terminals

R1~R5‧‧‧ resistance

PD‧‧‧Optical coupling element

PD1‧‧‧Photovoltaic diode

PD2‧‧‧Photovoltaic sensor

LL1‧‧‧ low logic level signal

LH1‧‧‧ logic signal

P1‧‧‧ first pulse signal

P2‧‧‧Second pulse signal

N1, N2‧‧‧ switching points

S1‧‧‧ first signal

S2‧‧‧ second signal

Td‧‧‧ preset time

S701~S713‧‧‧ Process steps

1 is a functional block diagram of an AC/DC power supply circuit according to an embodiment of the present invention.

2 is a circuit diagram of an optocoupler conversion unit and a trigger unit according to another embodiment of the present invention.

3 is a circuit diagram of a logic unit and a switching unit according to another embodiment of the present invention.

4A is a waveform diagram of signals received by an AC/DC power supply circuit receiving AC power according to another embodiment of the present invention.

4B is a schematic diagram of a switching state of a switching unit according to another embodiment of the present invention.

FIG. 5A is a waveform diagram of signals received by an AC/DC power supply circuit receiving DC power according to another embodiment of the present invention.

FIG. 5B is a schematic diagram of a switching state of a switching unit according to another embodiment of the present invention.

FIG. 6 is a circuit diagram of an AC/DC power supply circuit applicable to another embodiment of the present invention.

FIG. 7 is a flowchart of a method for selecting an AC/DC power supply according to another embodiment of the present invention.

1 is a functional block diagram of an AC/DC power supply circuit according to an embodiment of the present invention. Please refer to Figure 1. An AC/DC power supply circuit 1 is electrically connected to an alternating current or a continuous current through a pair of input terminals L1 and L2, and the AC/DC power supply circuit 1 is electrically connected to an isolated power conversion circuit having a rectifier circuit 9, and an AC/DC power supply. Circuit 1 package An optocoupler conversion unit 10, a trigger unit 12, a logic unit 14, and a switching unit 16 are included. In practice, the optocoupler conversion unit 10 is electrically connected to an alternating current (or direct current) and a trigger unit 12. The logic unit 14 is electrically connected to the trigger unit 12 and the switching unit 16. The switching unit 16 is coupled to the rectifier circuit 9.

Generally, the power supply circuit for both AC and DC is output to the back end circuit 8 through the rectifier circuit 9. When the direct current passes through the rectifying circuit 9, the loss of the diode on the rectifying circuit 9 causes ironing and power consumption, thereby affecting the efficiency of the direct current output. However, the AC/DC power supply circuit 1 of the present embodiment transmits AC or DC power. When the AC/DC power supply circuit 1 distinguishes the DC power, the present embodiment transmits the DC power directly to the rectifier circuit 9 to output to the back end circuit 8 through the design of the switching unit 16, thereby reducing the loss of the diode on the rectifier circuit 9, Hot and power consumption.

When the AC/DC power supply circuit 1 distinguishes the AC power, the present embodiment transmits the AC power through the rectifier circuit 9 to output to the back end circuit 8 through the design of the switching unit 16. Thereby, the embodiment achieves the effects of AC/DC dual-use and reducing the loss of the diode, the ironing and the power consumption on the rectifier circuit 9.

Further, the optocoupler conversion unit 10 is realized by, for example, a diode and a photo-diode. This embodiment does not limit the aspect of the optocoupler conversion unit 10. In practice, the optocoupler conversion unit 10 is used to distinguish between alternating current or direct current. For example, the frequency of the alternating current is typically 50 Hz or 60 Hz. Therefore, after the alternating current enters the optocoupler conversion unit 10, part of the alternating current will be converted into the photovoltaic pulse signal, and the other part of the alternating current will be isolated by the optocoupler conversion unit 10. However, direct current has directionality. Therefore, after the direct current enters the optocoupler conversion unit 10, the direct current will be isolated by the optocoupler conversion unit 10, or the direct current will cause the optocoupler conversion unit 10 to be turned on. That is to say, the optocoupler conversion unit 10 can be regarded as a detection circuit capable of resolving alternating current or direct current.

The trigger unit 12 is coupled to the optocoupler conversion unit 10 . In practice, a part of the AC power is converted into a pulse signal by the optocoupler conversion unit 10 and output to the trigger unit 12. The DC power will be isolated by the optocoupler conversion unit 10, or the DC power will cause the optocoupler The conversion unit 10 is turned on. Those skilled in the art can freely design an optocoupler conversion unit 10 that can distinguish between alternating current or direct current. The trigger unit 12 is implemented, for example, by an inverting flip-flop. The trigger unit 12 is used to trigger the logic unit 14, causing the logic unit 14 to control the switching operation of the switching unit 16.

The logic unit 14 is coupled to the contact unit 12. In practice, logic unit 14 is implemented, for example, by a delay flip-flop, a buffer flip-flop, or a logic with a reset circuit. This embodiment does not limit the aspect of the logic unit 14. In addition, the switching unit 16 is coupled to the logic unit 14 . In practice, the switching unit 16 is implemented, for example, by one or a combination of an electronic switch and a mechanical switch. The electronic switch is, for example, a bipolar junction transistor, a field effect transistor or a gate transistor. The mechanical switch is, for example, a relay. This embodiment does not limit the aspect of the switching unit 16.

When the optocoupler conversion unit 10 receives the alternating current via the pair of input terminals L1 and L2, the optocoupler conversion unit 10 outputs a first pulse signal to the trigger unit 12, and the trigger unit 12 outputs according to the first pulse signal. A second pulse signal is sent to the logic unit 14. The logic unit 14 outputs a first signal to the switching unit 16 according to the second pulse signal. The switching unit 16 is in a first state according to the first signal. The first state is that the switching unit 16 is in a normally closed state to cause the alternating current to be converted to a back end circuit 8 via the rectifying circuit 9.

When the optocoupler conversion unit 10 receives the DC power through the pair of input terminals L1 and L2, the trigger unit 12 outputs a logic signal to the logic unit 14, and the logic unit 14 outputs a delay according to the logic signal after a predetermined time. The second signal is sent to the switching unit 16, and the switching unit 16 is in a second state according to the second signal. The second state is that the switching unit 16 is in a normally open state so that direct current is directly bypassed by the rectifier circuit 9 to supply the back end circuit 8.

Based on the above, the present embodiment designs the AC/DC power supply circuit 1 with the concept of alternating current having a frequency so as not to change the original input mode, and avoids the loss point or path of the diode on the rectifier circuit 9 when receiving the direct current. In order to enhance the original output efficiency. Of course, the AC/DC power supply circuit 1 of the embodiment can also be applied to multi-national frequencies. Range (50Hz/60Hz).

Next, the detailed circuit of the optocoupler conversion unit 10 and the trigger unit 12 in FIG. 1 and its operation are further explained. 2 is a circuit diagram of an optocoupler conversion unit and a trigger unit according to another embodiment of the present invention. Please refer to Figure 2. For convenience of explanation, the present embodiment is described by an AC frequency of 60 Hz.

In detail, the optocoupler conversion unit 10 includes a diode D1 and an optical coupling element PD, and the diode D1 is connected in parallel with the optical coupling element PD. The optical coupling element PD includes a photovoltaic diode PD1 and a photovoltaic sensor PD2. The photovoltaic sensor PD2 is optically coupled to the photovoltaic diode PD1. The photovoltaic diode PD1 is, for example, an optocoupler inner light-emitting diode. The diode D1 and the photovoltaic diode PD1 are connected in reverse. For example, the cathode of the diode D1 is coupled to the anode of the photovoltaic diode PD1 and the input terminal L1. The anode of the diode D1 is coupled to the cathode of the photovoltaic diode PD1 and the input terminal L2. Thereby, the optical coupling element PD is turned on during the positive half cycle of the alternating current and is turned off during the negative half cycle of the alternating current, whereby the optical coupling element PD generates a signal of, for example, 0101 when the alternating current is input. When the pair of input terminals L1, L2 receive DC power, the diode D1 is turned off and the optical coupling element PD is turned on.

For example, the photovoltaic sensor PD2 is coupled between the 3.3 volt working voltage source VCC and the ground. The photovoltaic diode PD1 is, for example, a light emitter, and the photovoltaic sensor PD2 is, for example, a light detector. When the optical coupling element PD is turned on, the alternating current flows through the photovoltaic diode PD1 to cause the photovoltaic diode PD1 to generate an optical coupling signal to the photovoltaic sensor PD2. The photovoltaic sensor PD2 is turned on according to the optocoupler signal to couple the 3.3 volt working voltage source VCC to the ground. On the contrary, when the optical coupling element PD is turned off, the photovoltaic diode PD1 and the photovoltaic sensor PD2 are both in an off state. Therefore, the 3.3 volt working voltage source VCC cannot be coupled to the ground. Thereby, the trigger unit 12 receives the first pulse signal.

When 60 Hz AC power is input from the pair of input terminals L1, L2, the photovoltaic diode PD1 is turned on during the positive half cycle of the alternating current. Therefore, the input of the trigger unit 12 is, for example, a 60 Hz square wave, whereby the trigger unit 12 continues to output a PWM, for example. The second pulse signal. On the contrary, when the direct current is input from the pair of input terminals L1, L2, the photovoltaic diode PD1 is turned on when the direct current is turned on, and the diode D1 is turned off. Therefore, the input of the trigger unit 12 is, for example, a low logic level, whereby the trigger unit 12 continuously outputs a logic signal of a high logic level.

In addition, the trigger unit 12 is, for example, an Inverting Schmitt trigger. The input terminal I1 of the trigger unit 12 is coupled to the photovoltaic sensor PD2, and the output terminal O1 is coupled to the logic unit 14. This embodiment does not limit the aspect of the trigger unit 12.

Next, the detailed circuit of the logic unit 14 and the switching unit 16 in FIG. 1 and its operation will be further explained. 3 is a circuit diagram of a logic unit and a switching unit according to another embodiment of the present invention. Please refer to Figure 3. The logic unit 14 is, for example, a reset circuit with a Manual Reset (Reset Circuit with Manual Reset). The switching unit 16 is, for example, one or a combination of a transistor Q1 and a relay 160. The relay 160 is, for example, a single pole double throw relay (SPDT). In practice, the input terminal I2 of the logic unit 14 is coupled to the reset output terminal O1 of the trigger unit 12. The output terminal RST of the logic unit 14 is coupled to the base of the bipolar junction transistor Q1, and the collector is coupled to the relay 160, and the emitter is coupled to the ground.

Further, the trigger unit 12 outputs a second pulse signal such as a fixed pulse of 16.67 microseconds as an input to the logic unit 14, wherein each pulse period of 60 Hz is approximately 16.67 microseconds. Therefore, in the AC input state, the input terminal I2 of the logic unit 14 is triggered by the second pulse signal every pulse period (about 16.67 microseconds), whereby the output terminal RST of the logic unit 14 outputs the first signal. The first signal is a signal with a low logic level.

In addition, in the DC input state, the input terminal I2 of the logic unit 14 receives the logic signal of the high logic level, and the logic unit 14 outputs a second signal, wherein the second signal is delayed by the logic unit 14 by a preset time. Then, the signal is converted to a high logic level by a low logic level. For example, in the DC input state, the logic unit 14 transitions from a low logic level to a high logic level signal signal after 200 microseconds. For the second signal.

It is worth noting that the preset time is greater than each pulse period of the second pulse signal. For example, a 50 Hz alternating current will cause the trigger unit 12 to output a second pulse signal, such as a fixed pulse of 20 microseconds, as an input to the logic unit 14. Therefore, if the preset time is, for example, 25 microseconds, 30 microseconds, or other numerical microseconds, the logic unit 14 is triggered to perform the delay transition operation every 20 microseconds under the alternating current input condition. On the other hand, if the preset time is less than each pulse period of the second pulse signal, for example, 15 microseconds, the logic unit 14 will not normally control the operation of the switching unit 16 to switch to the alternating current. That is to say, the AC/DC power supply circuit 1 cannot achieve the above effects. A person skilled in the art can freely design a preset time.

In addition, the operation of the relay 160 is based on the transistor Q1 that is turned on or off to switch the operation of the single pole double throw. For example, in the AC input condition, the transistor Q1 is turned off, and the relay 160 is in a state of being coupled to the rectifier circuit 9. On the contrary, in the DC input condition, the transistor Q1 is turned on, and the relay 160 is coupled to the state of directly bypassing the rectifying circuit 9, that is, the relay 160 will be switched to avoid the input terminals L1, L2 from being coupled to In the circuit of the diode of the rectifier circuit 9.

The AC/DC power supply circuit 1 of this embodiment can be seen from the contents of FIG. 1, FIG. 2 and FIG. In the AC input state, the optical coupling element PD is turned on during the positive half cycle of the alternating current, whereby the optocoupler conversion unit 10 outputs the first pulse signal to the trigger unit 12. The trigger unit 12 outputs the second pulse signal to the logic unit 14 to keep the logic unit 14 continuously triggered and delayed, whereby the logic unit 14 outputs a first signal such as a low logic level to the switching unit 16. Therefore, the alternating current will pass through the rectifying circuit 9.

On the other hand, in the DC input state, the optical coupling element PD is turned on when the DC power is turned on, so that the trigger unit 12 outputs the logic signal LH1 to the logic unit 14 to delay the signal output by the logic unit 14 after a predetermined time. The logic unit 14 outputs a second signal of a high logic level, such as a delayed transition, to the switching unit 16. Therefore, the direct current will bypass the rectifier circuit 9 directly to be coupled to the back end circuit 8.

As can be seen from FIG. 1 , FIG. 2 and FIG. 3 , the optocoupler conversion unit 10 receives the pair of inputs. When the terminals L1 and L2 receive the alternating current 24V, the optical coupling element PD will output DC 12V, and the DC 12V is input to its control voltage circuit to generate the control voltage 3.3V. At this time, the optical coupling element PD has its photovoltaic diode PD1 because of the alternating current mode. The conduction mode is only positive for half a week. Therefore, the photovoltaic sensor PD2 of the isolated end of the optical coupling element PD is thus turned on to obtain a signal such as a switch generating logic 1 and 0.

The repeating period of the signal such as 01 is the reciprocal of the frequency of the commercial power of 60 Hz (for example, 16.67 ms), and the signal is directly input to the control end of the logic unit 14 such as the delay circuit. The logic unit 14 is a signal output after the control voltage reaches the 3.3V voltage level, and the output signal is delayed by the low logic level signal by a delay of 200ms and then converted to a high logic level.

However, under the AC input, the control signal of the logic unit 14 is 16.67 ms and the signal of the logic such as 01 is continuously input, so that the logic unit 14 is kept in the state of its output Keep Low 200 ms. That is to say, the logic unit 14 keeps the signal outputting the low logic level at all times, and then regards this output as the input of the coil of the switching unit 16 of the relay coupled to the control terminal of the transistor Q1. When the control terminal of the transistor Q1 is at a low logic level, the transistor Q1 is turned off, so that the coil of the relay cannot obtain the voltage and the single-pole double-throw relay cannot be operated, whereby the alternating current passes through the bridge rectifier circuit 9.

In other words, if the current input is changed from AC 24V to DC 12V input, 12V and 3.3V are generated in the same way as above. When DC 12V is input, the photo-coupling element PD has positive and negative polarity of the photovoltaic diode PD1 end, and the optical coupling element PD is also in a conducting state, and the photovoltaic sensor PD2 outputs a signal with a low logic level, such as by The trigger unit 12 of the device then converts to a signal with a high logic level, and then inputs the signal to the control terminal of the logic unit 14 such as the delay circuit. Once the control input of the logic unit 14 is a signal with a high logic level, the output will be After a delay of 200ms, the signal is converted to a high logic level. The signal of the high logic level is input to the coil of the relay and coupled to the control terminal of the transistor Q1. The transistor Q1 is turned on to form a loop, and the coil of the relay obtains a voltage to generate an action. Bypassing the positive and negative terminals (ByPass) of the original input to the bridge The rear of the flow circuit 9 further achieves the function of loss of the bridgeless rectifier.

Next, the detailed operation of the AC power supply circuit of FIG. 1 to receive the AC power is further explained. FIG. 4A is a waveform diagram of signals received by the AC/DC power supply circuit 1 according to another embodiment of the present invention. FIG. 4B is a schematic diagram of a switching state of the switching unit 16 according to another embodiment of the present invention. Please refer to FIG. 4A and FIG. 4B. FIG. 4A illustrates a first pulse signal P1, a second pulse signal P2, and a first signal S1. The first pulse signal P1 of the input terminal I1 of the trigger unit 12 and the second pulse signal P2 of the output terminal O1 are inverted pulse signals. Each pulse of the second pulse signal P2 is used to trigger the logic unit 14 to cause the logic unit 14 to output a first signal S1. The first signal S1 is a low logic level.

In detail, the input terminal 12 of the logic unit 14 receives the signal of the high logic level once, and the output terminal RST of the logic unit 14 will delay the output of the high logic level in the transition state after the preset time Td. The pulse period of the second pulse signal P2 is less than the preset time Td. Therefore, within the preset time Td, the logic unit 14 is triggered to recalculate the delayed preset time Td; during the next preset time Td, the logic unit 14 is also triggered to recalculate the delayed preset time. Td, whereby the output RST of the logic unit 14 outputs a first signal S1, such as a low logic level, to the base of the transistor Q1, whereby the transistor Q1 is not turned on. Therefore, the relay 160 cannot be energized and does not operate. That is, the alternating current will pass through the original rectifier circuit 9 to the back end circuit 8.

In addition, FIG. 4B corresponds to the operational aspect of the relay 160 of FIG. 4A. The transistor Q1 is turned off according to the first signal S1 outputted by the output terminal RST of the logic unit 14, whereby the relay 160 passes the turned-off transistor Q1 to pass the alternating current through the original rectifier circuit 9 to the back-end circuit 8.

Next, the detailed operation of the direct current power supply circuit of FIG. 1 to receive the direct current power is further explained. FIG. 5A is a diagram showing an AC/DC power supply circuit receiving a straight line according to another embodiment of the present invention; FIG. The signal waveform of the current. FIG. 5B is a schematic diagram of a switching state of a switching unit according to another embodiment of the present invention. Please refer to FIG. 5A and FIG. 5B. FIG. 5A illustrates a low logic level signal LL1, a logic signal LH1, and a second signal S2. The low logic level signal LL1 and the logic signal LH1 are inverted signals. The high logic level of the logic signal LH1 is used to trigger the logic unit 14 to cause the logic unit 14 to output a second signal S2. The second signal S2 is a signal that “the logic unit 14 is delayed by a preset logic time Td to change a low logic level to a high logic level”.

In detail, the input terminal I2 of the logic unit 14 receives the high logic level signal once, and the output terminal RST of the logic unit 14 is delayed by the preset time Td and then outputs a second high logic level in a transition state. Signal S2. The logic signal LH1 is a one-time high logic level signal. Therefore, the output RST of the logic unit 14 outputs a second signal S2 of a high logic level that is delayed by a predetermined time Td, whereby the output RST of the logic unit 14 converts the output from a low logic level. The second signal S2 of the high logic level is supplied to the base of the transistor Q1, whereby the transistor Q1 is turned on. Therefore, the relay 160 is energized to operate. That is to say, the direct current will directly bypass the original rectifier circuit 9 to the back circuit 8.

In addition, FIG. 5B corresponds to the operational aspect of the relay 160 of FIG. 5A. The transistor Q1 is turned on according to the second signal S2 outputted by the output terminal RST of the logic unit 14, whereby the relay 160 directly bypasses the original rectifier circuit 9 to the back-end circuit 8 according to the turned-on transistor Q1. .

FIG. 6 is a circuit diagram of an applicable AC/DC power supply circuit 1 according to another embodiment of the present invention. Please refer to Figure 6. In practice, the back end circuit 8 is, for example, a flyback isolated power conversion circuit, a flyback circuit, a conversion circuit, or a load circuit; or the back end circuit 8 is, for example, a medical device, a power supply device, an electronic device, or the like. Circuit. This embodiment does not limit the aspect of the back end circuit 8. The AC/DC power supply circuit 1 of the embodiment can be applied to an AC/DC electrical device.

For example, the pair of input terminals L1, L2 in FIG. 6 are coupled to, for example, FIG. In the AC/DC power supply circuit 1, the functions of "resolvable AC/DC", "avoiding the power loss of the diode in the rectifier circuit 9", and "increasing the output power of the DC power" are achieved. The switching point of FIG. 4B and/or FIG. 5B is coupled to, for example, the switching point in FIG. 6 . This embodiment does not limit the aspect in which the AC/DC power supply circuit 1 is applied to the back end circuit 8.

FIG. 7 is a flowchart of a method for selecting an AC/DC power supply according to another embodiment of the present invention. Please refer to Figure 7. An AC/DC power supply selection method is applicable to electrically connect an alternating current or a continuous current through a pair of input terminals L1 and L2, and an AC/DC power supply circuit 1 is electrically connected to an isolated power conversion circuit having a rectifier circuit 9. The AC/DC power supply selection method includes the following steps: In step S701, it is determined whether an optocoupler conversion unit 10 receives an alternating current. If the result of the determination in the step S701 is YES, the step S703 is performed, the optocoupler conversion unit 10 outputs a first pulse signal P1 to the trigger unit 12, and the trigger unit 12 outputs a second pulse signal according to the first pulse signal P1. P2 is given to logic unit 14.

Next, in step S707, the logic unit 14 outputs a first signal S1 to the switching unit 16 according to the second pulse signal P2, and the switching unit 16 is in a first state according to the first signal S1. In step S709, the first state is that the switching unit 16 is in the normally closed state, so that the alternating current is converted to a back end circuit 8 via the rectifying circuit 9.

If the result of the determination in step S701 is no, then in step S705, the trigger unit 12 outputs a logic signal LH1 to the logic unit 14. In step S711, the logic unit 14 outputs a second signal S2 that is delayed by a predetermined time Td to the switching unit 16 according to the logic signal LH1, and the switching unit 16 is in a second state according to the second signal S2. Next, in step S713, the second state is that the switching unit 16 is in the normally open state, so that the direct current is directly bypassed by the rectifier circuit 9 to supply the back end circuit 8.

In summary, in the AC/DC power supply circuit of the present invention, in the AC input condition, the optocoupler conversion unit is turned on during the positive half cycle of the alternating current, so that the trigger unit continuously triggers the logic unit, so the logic unit is continuously triggered and delayed. The logic unit outputs a first signal to the switching unit. Therefore, the AC power will pass through the rectifier circuit. to In the DC input state, the optocoupler conversion unit is turned on during the DC power, so that the trigger unit triggers the logic unit, so the signal output by the logic unit is delayed by a predetermined time, and then the logic unit outputs a second signal to the switch. unit. Therefore, the direct current will bypass the rectifier circuit directly to couple to the back end circuit. It can be seen from this that the present embodiment does achieve the output power of the boost circuit.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

1‧‧‧AC power supply circuit

8‧‧‧ Back-end circuit

9‧‧‧Rectifier circuit

10‧‧‧optical coupling unit

12‧‧‧Trigger unit

14‧‧‧Logical unit

16‧‧‧Switch unit

D0‧‧‧ bypass path

L1, L2‧‧‧ input terminals

Claims (10)

An AC/DC power supply circuit is electrically connected to an alternating current or a continuous current through a pair of input terminals, and the AC/DC power supply circuit is electrically connected to an isolated power conversion circuit having a rectifier circuit, the AC/DC power supply circuit comprising: An optocoupler conversion unit; a trigger unit coupled to the optocoupler conversion unit; a logic unit coupled to the trigger unit; and a switching unit coupled to the logic unit; wherein the optocoupler conversion unit is When the pair of input terminals receives the alternating current, the optocoupler converting unit outputs a first pulse signal to the trigger unit, and the trigger unit outputs a second pulse signal to the logic unit according to the first pulse signal. The logic unit outputs a first signal to the switching unit according to the second pulse signal, and the switching unit is in a first state according to the first signal, so that the alternating current is converted to a back end via the rectifying circuit. a circuit; wherein, when the optocoupler conversion unit receives the DC power through the pair of input terminals, the trigger unit outputs a logic signal to the logic unit The logic unit outputs a second signal delayed by a predetermined time to the switching unit according to the logic signal, and the switching unit is in a second state according to the second signal, so that the direct current directly bypasses the A rectifier circuit is supplied to the back end circuit. The AC/DC power supply circuit of claim 1, wherein the first state is that the switching unit is in a normally closed state, and the second state is that the switching unit is in a normally open state. The AC/DC power supply circuit of claim 1 or 2, wherein the optocoupler conversion unit comprises a diode and an optical coupling element, and the diode is connected in parallel with the optical coupling element. An AC/DC power supply circuit as described in claim 3, wherein the optical coupling The component includes a photovoltaic diode and a photovoltaic inductor. The photovoltaic diode is connected in reverse with the diode. The photovoltaic sensor is coupled to the trigger unit, and the optical coupling component is turned on during the positive half cycle of the alternating current. And the negative half cycle of the alternating current is turned off, and when the pair of input terminals receives the direct current, the diode is turned off and the optical coupling element is turned on. The AC/DC power supply circuit of claim 1 or 2, wherein each pulse of the second pulse signal is used to trigger the logic unit, so that the logic unit outputs the first signal, the first signal A signal with a low logic level. The AC/DC power supply circuit of claim 1 or 2, wherein the logic signal is used to trigger the logic unit, so that the logic unit outputs the second signal, and the second signal is delayed by the logic unit. After the preset time, the signal is converted to a high logic level by a low logic level. The AC/DC power supply circuit of claim 1 or 2, wherein each pulse period of the second pulse signal is less than the preset time. The AC/DC power supply circuit of claim 1 or 2, wherein the trigger unit is an inverting flip-flop, the logic unit is a logic circuit with a reset circuit, and the switching unit is a transistor and a One or a combination of relays, wherein the relay is a single pole double throw relay. An AC/DC power supply selection path method is adapted to electrically connect an alternating current or a continuous current through a pair of input terminals, and an AC/DC power supply circuit is electrically connected to an isolated power conversion circuit having a rectifier circuit, the AC/DC power supply The method of selecting a path includes: determining whether an optocoupler conversion unit receives the alternating current, and if the determination result is yes, the optocoupler converting unit outputs a first pulse signal to a trigger unit, and the trigger unit is configured according to the first The pulse signal outputs a second pulse signal to a logic unit; the logic unit outputs a first signal to a switching unit according to the second pulse signal, and the switching unit is in a first according to the first signal State to The alternating current is converted to a back end circuit via the rectifying circuit; if the determination result is no, the triggering unit outputs a logic signal to the logic unit; the logic unit outputs a delay according to the logic signal for a predetermined time and then turns The second signal of the state is given to the switching unit, and the switching unit is in a second state according to the second signal, so that the direct current directly bypasses the rectifying circuit to supply the back end circuit. The AC/DC power supply selection path method according to claim 9, wherein the first state is that the switching unit is in a normally closed state, and the second state is that the switching unit is in a normally open state.