CN219181179U

CN219181179U - Power protection circuit, power circuit, circuit board and air conditioner

Info

Publication number: CN219181179U
Application number: CN202223061254.3U
Authority: CN
Inventors: 周杰
Original assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Hefei Shiyan Electronic Technology Co Ltd
Current assignee: Guangzhou Shiyuan Electronics Thecnology Co Ltd; Hefei Shiyan Electronic Technology Co Ltd
Priority date: 2022-11-18
Filing date: 2022-11-18
Publication date: 2023-06-13
Anticipated expiration: 2032-11-18

Abstract

The utility model discloses a power supply protection circuit, a power supply circuit, a circuit board and an air conditioner, wherein the power supply protection circuit is connected with a rectification filter circuit, the rectification filter circuit is used for outputting power supply voltage, the rectification filter circuit comprises an anti-surge resistor, and the power supply protection circuit comprises: the input end of the hysteresis comparison module is input with a reference voltage and a sampling voltage based on a power supply voltage, and the output end of the hysteresis comparison module is used for outputting a driving voltage; the switch module is connected with the output end of the hysteresis comparison module, is connected with the anti-surge resistor in parallel, and is used for driving the switch module to be turned on or turned off by the driving voltage; the utility model can effectively improve the reliability of the power supply protection circuit.

Description

Power protection circuit, power circuit, circuit board and air conditioner

Technical Field

The present utility model relates to the field of electronic circuits, and in particular, to a power protection circuit, a power circuit, a circuit board, and an air conditioner.

Background

Because the frequency conversion control circuit needs to convert AC to DC and then convert the AC to AC, a large electrolytic capacitor is used as a rectifying circuit on the circuit for converting commercial power to AC. In order to prevent the power-on surge, an NTC resistor or a metal film resistor is generally connected in series with the zero line or the live line of the power-on circuit, as shown in fig. 1. Because the resistance of the string is relatively large, the resistance is easy to heat and burn out and the circuit voltage is reduced in the working process of the actual inverter circuit due to the large current. Therefore, more relays are connected in parallel at two ends of the NTC resistor, after the large electrolytic capacitor is charged, the MCU is used for enabling the signal to attract the relays, the NTC circuit is shorted, and the problems of heating and the like of the NTC resistor are avoided.

However, when the MCU crashes or the software program runs out, the MCU cannot send out an enabling signal, so that the relay cannot be attracted, and the reliability of protection is low.

Thus, there is a need for improvement and advancement in the related art.

Disclosure of Invention

The utility model aims to provide a power supply protection circuit, a power supply circuit, a circuit board and an air conditioner, which can effectively improve the protection reliability.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

the embodiment of the application provides a power protection circuit, is connected with rectification filter circuit, and rectification filter circuit is used for exporting mains voltage, and rectification filter circuit includes anti surge resistance, and power protection circuit includes:

the input end of the hysteresis comparison module is input with a reference voltage and a sampling voltage based on a power supply voltage, and the output end of the hysteresis comparison module is used for outputting a driving voltage;

the switch module is connected with the hysteresis comparison module, is connected with the anti-surge resistor in parallel, and is used for being driven to be conducted or disconnected by the driving voltage.

The embodiment of the application also provides a power supply circuit, which comprises a rectification filter circuit and the power supply protection circuit, wherein the rectification filter circuit comprises an anti-surge resistor, the rectification filter circuit is connected with the power supply protection circuit, and the rectification filter circuit is used for outputting power supply voltage; the power supply protection circuit is connected with the anti-surge resistor in parallel and is used for being conducted or disconnected according to the power supply voltage.

The embodiment of the application also provides an air conditioner comprising the power supply circuit.

Compared with the prior art, the utility model provides the power supply protection circuit, the power supply circuit, the circuit board and the air conditioner, wherein the power supply protection circuit is connected or disconnected according to the power supply voltage of the rectification filter circuit through the hysteresis comparison module, so that the short circuit or the passage of the anti-surge resistor can be further caused, and the heating damage of the anti-surge resistor caused by overlarge current can be effectively avoided; and the hardware circuit structure is arranged to control the short circuit or the passage of the anti-surge resistor, so that the timeliness of the protection of the power supply protection circuit can be ensured, and the reliability of the power supply protection circuit is further improved.

Drawings

Fig. 1 is a circuit diagram of a conventional power supply circuit.

Fig. 2 is a block diagram of a power supply circuit according to the present utility model.

Fig. 3 is a block diagram of a hysteresis comparison module in the power supply circuit according to the present utility model.

Fig. 4 is a circuit diagram of a power protection circuit in the power circuit provided by the utility model.

Detailed Description

In order to make the objects, technical solutions and effects of the present utility model clearer and more specific, the present utility model will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

Referring to fig. 2, the power supply circuit provided by the present utility model includes a rectifying and filtering circuit 10 and a power supply protection circuit 20, wherein the rectifying and filtering circuit 10 is connected with the power supply protection circuit 20; the rectification filter circuit 10 comprises an anti-surge resistor T0, an EMI filter module and a rectification filter module; the EMI filtering module is connected with the anti-surge resistor T0, and the rectifying and filtering module is connected with the EMI filtering module and the power supply protection circuit 20; the anti-surge resistor T0 is used for inhibiting surge current of the power circuit in the power-on process; the EMI filtering module is used for eliminating electromagnetic interference in the power supply; the rectification filter module is used for rectifying and filtering the input alternating current and outputting direct current.

In some embodiments, referring to fig. 3, the emi filter module includes a first capacitor C1, a second capacitor C2, a first inductor L1 and a second inductor L2; one end of a first capacitor C1 and a 3 rd pin of a first inductor L1 are connected with a zero line, the other end of the first capacitor C1 and one end of a second inductor L2 are connected with a live line, the other end of the second inductor L2 is connected with one end of an anti-surge resistor T0, a 4 th pin of the first inductor L1 is connected with the other end of the anti-surge resistor T0, a 2 nd pin of the first inductor L1 and one end of the second capacitor C2 are connected with a rectifying and filtering module, and the other ends of the 1 st pin of the first inductor L1 and the second capacitor C2 are connected with the rectifying and filtering module; in this embodiment, the first capacitor C1 and the second capacitor C2 are both X capacitors, and the X capacitors are used to eliminate differential mode interference in the circuit.

In some embodiments, the rectifying and filtering module includes a rectifying bridge BD1 and a third capacitor C3, where a 1 st leg of the rectifying bridge BD1 and one end of the third capacitor C3 are both connected to the power supply voltage output end, a 2 nd leg of the rectifying bridge BD1 is connected to one end of the second capacitor C2, a 3 rd leg of the rectifying bridge BD1 is connected to the other end of the second capacitor C2, and a 4 th end of the rectifying bridge BD1 and the other end of the third capacitor C3 are both grounded; the third capacitor C3 is a large electrolytic capacitor, and can perform filtering processing on the direct current output by the rectifier bridge BD1, so as to improve stability of the power supply voltage.

In some embodiments, the rectifying and filtering circuit 10 further includes a varistor M1, one end of the varistor M1 is connected to the zero line, and the other end of the varistor M1 is connected to the live line, where the varistor M1 is used for resisting surge voltage, so as to improve the safety of the power circuit.

In the specific embodiment, the power protection circuit 20 includes a hysteresis comparison module 21 and a switch module 22; the hysteresis comparison module 21 is connected with the rectification filter circuit 10, the input end of the hysteresis comparison module 21 inputs the reference voltage and the sampling voltage based on the power supply voltage, and the output end of the hysteresis comparison module 21 is used for outputting the driving voltage; the switch module 22 is connected with the output end of the hysteresis comparison module 21, the switch module 22 is connected with the anti-surge resistor T0 in parallel, and the driving voltage is used for driving the switch module 22 to be turned on or turned off; since the switch module 22 has the anti-surge resistor T0 connected in parallel, when the switch module 22 is turned on, the anti-surge resistor T0 is short-circuited, and when the switch module 22 is turned off, the anti-surge resistor T0 is connected to the circuit to maintain the on state.

The anti-surge resistor T0 may be a temperature coefficient resistor or a fixed resistance resistor. The anti-surge resistor T0 is used for inhibiting surge current in the power-on process so as to provide surge protection for a power circuit.

In the utility model, at the moment of powering on the power circuit, the anti-surge resistor T0 is in a channel state, and at the moment, the charging of the third capacitor C3 is limited through the anti-surge resistor T0; when the third capacitor C3 is charged to the set range, the voltage of the third capacitor C3 is increased to a certain value, that is, the power supply voltage is increased to a certain value, if the sampling voltage obtained by the hysteresis comparison module 21 based on the power supply voltage is greater than the first preset voltage, the driving voltage of the first level signal is output, and the switch module 22 is turned on according to the first level signal, so that the anti-surge resistor T0 is short-circuited; when the voltage of the third capacitor C3 decreases, the output power supply voltage decreases, that is, the sampling voltage input by the hysteresis comparison module 21 decreases to be smaller than the second preset voltage based on the power supply voltage, a second level signal is output, and the switch module 22 is turned off according to the second level signal, so that the anti-surge resistor T0 is turned on.

According to the utility model, the hysteresis comparison module 21 is connected or disconnected according to the power supply voltage of the rectifying and filtering circuit 10, so that the short circuit or the passage of the anti-surge resistor T0 can be further realized, and the heating damage of the anti-surge resistor T0 caused by overlarge current can be effectively avoided; in addition, the hardware circuit structure is arranged to control the short circuit or the passage of the anti-surge resistor T0, so that the timeliness of the protection of the power supply protection circuit 20 can be ensured, and the reliability of the power supply protection circuit 20 is further improved; meanwhile, the hysteresis comparison module 21 outputs level signals according to two different preset voltages, so that the hysteresis control effect can be achieved, the switch module 22 is prevented from being turned on or off under the condition of normal fluctuation of the power supply voltage of the third capacitor C3, the switch module 22 is prevented from being turned on or off too sensitively, and the reliability of the power supply protection circuit 20 is further improved.

In some embodiments, the hysteresis comparison module 21 includes a voltage dividing resistor group 211 connected to the rectifying and filtering circuit 10, where an input end of the voltage dividing resistor group 211 inputs a power supply voltage, and an output end of the voltage dividing resistor group 211 is used for outputting the sampling voltage, that is, the voltage dividing resistor group 211 samples the power supply voltage and then outputs the sampling voltage; the hysteresis comparison unit 212, the hysteresis comparison unit 212 includes two input ends, one of which is connected with the voltage dividing resistor group 211, and the other of which inputs the reference voltage; the hysteresis comparison unit 212 is configured to output a driving signal of a first level signal when the sampling voltage is greater than a first preset voltage, or output a driving signal of a second level signal when the sampling voltage is less than a second preset voltage; the voltage dividing resistor group 211 is arranged to divide and sample the power supply voltage of the rectified filter current to obtain the sampling voltage, and the size of the power supply voltage is determined according to the size of the sampling voltage, so that the charging voltage condition of the third capacitor C3 can be determined; then, the hysteresis comparison unit 212 outputs a driving signal of the first level signal or the second level signal according to the magnitude of the sampling voltage, so that the short circuit or the passage of the anti-surge resistor T0 is controlled through hardware, and the reliability of protection is improved.

As an embodiment, referring to fig. 4 together, the voltage dividing resistor set 211 includes a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4, one end of the first resistor R1 is connected to one end of the third capacitor C3, the other end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4 and the input end of the hysteresis comparing unit 212, and the other end of the fourth resistor R4 is grounded, so as to form a voltage division by setting several resistors, so as to realize effective detection of the power supply voltage.

As one embodiment, the hysteresis comparison unit 212 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a comparator OP1; one end of the fifth resistor R5 is connected with the other end of the third resistor R3, the other end of the fifth resistor R5 is connected with the normal phase input end of the comparator OP1, one end of the sixth resistor R6 is connected with the normal phase input end of the comparator OP1, the other end of the sixth resistor R6 is connected with the output end of the comparator OP1, one end of the seventh resistor R7 and one end of the eighth resistor R8 are both connected with the reverse phase input end of the comparator OP1, the other end of the seventh resistor R7 is connected with electricity, the other end of the eighth resistor R8 is grounded, and the output end of the comparator OP1 is connected with the switch module 22.

The eighth resistor R8 and the ninth resistor R9 form a voltage dividing circuit, which divides the input voltage (5V in the present embodiment) connected to the seventh resistor R7 and provides a reference voltage for the comparator OP1; the sixth resistor R6 is a feedback resistor to provide a hysteresis comparison voltage to the comparator OP1, so that the comparator OP1 can have a hysteresis comparison process. Specifically, the reference voltage is Uref, the sampling voltage is U1, and U2 is the positive input voltage of the comparator OP1; according to the circuit structure and the characteristics of the comparator OP1 in the present embodiment, uref=5r8/(r7+r8) and (U1-U2)/r5= (U1-U0)/(r5+r6) are obtained, where U0 represents the output voltage of OP1, and u2=u1- (U1-U0) ×r5/(r5+r6) is obtained according to the above formula. When U2 is greater than Uref, the comparator OP1 outputs a high level, the output level of the comparator OP1 is low before, according to the fact that U2 is greater than Uref, uref < U1-U1 x R5/(R6+R5) is obtained, and U1> Uref (R6+R5)/R6 is obtained, when the sampling voltage is greater than Uref (R6+R5)/R5, namely a first preset voltage, the comparator OP1 outputs a first level signal, namely a high level, and the switch unit is conducted, so that the anti-surge resistor T0 is short-circuited; when U2 is smaller than Uref, the comparator OP1 outputs a low level, and the previous output level of the comparator OP1 is higher than Uref, and according to U2 being smaller than Uref, U1< Uref (r6+r5)/R6-U0R 5/R6 is obtained, and then when the sampling voltage U1 is smaller than Uref (r6+r5)/R6-U0R 5/R6, namely, a second preset voltage, the comparator OP1 outputs a second level signal, namely, a low level signal, the switching power supply is turned off, and the anti-surge resistor T0 is turned on. When the power supply circuit is powered on again so that the sampling voltage U1 is greater than the first preset voltage, the switch unit is turned on again, so that a hysteresis comparison process is formed, and further, the switch module 22 is turned on or off under the condition of normal fluctuation of the power supply voltage of the third capacitor C3 is effectively avoided, and the reliability of the power supply protection circuit 20 is improved.

In some embodiments, the switch module 22 includes a switch tube Q1, a ninth resistor R9 and a relay K1, where a first end of the switch tube Q1 is connected to an output end of the comparator OP1, a second end of the switch tube Q1 is grounded, a third end of the switch tube Q1 is connected to a 1 st pin of the relay K1, a 2 nd pin of the relay K1 is connected to the power supply through the ninth resistor R9, a 3 rd pin of the relay K1 is connected to one end of the anti-surge resistor T0, and a 4 th pin of the relay K1 is connected to the other end of the anti-surge resistor T0. As an embodiment, the switching transistor Q1 may be a triode or a MOS transistor, which is not limited in the present utility model. The switching tube Q1 is conducted according to the first level signal, so that the relay K1 is attracted, and the anti-surge resistor T0 is short-circuited; the switching tube Q1 is disconnected according to the second level signal, so that the relay K1 is powered off and disconnected, and then the anti-surge resistor T0 is connected, so that effective protection against the anti-surge resistor T0 is realized.

Furthermore, the utility model correspondingly provides a power supply protection circuit, which is used for effectively protecting the power supply circuit and ensuring the safety of the power supply circuit; in addition, the power supply circuit is protected through the power supply protection circuit of the hardware, so that the protection effect can be timely achieved relative to the software protection, the protection reliability is improved, and the power supply circuit is described in detail and is not repeated here.

Further, the utility model also correspondingly provides a circuit board which comprises the power supply circuit. It should be noted that the circuit board may be a whole block or may be formed by splicing a plurality of blocks. Since the power supply circuit is described in detail above, it will not be described in detail here.

Further, the present utility model also provides an air conditioner, which includes the above power circuit, and the detailed description of the power circuit is omitted here.

In summary, the utility model provides a power supply protection circuit, a power supply circuit, a circuit board and an air conditioner, wherein the power supply protection circuit is connected or disconnected according to the power supply voltage of a rectifying and filtering circuit through a hysteresis comparison module, so that the short circuit or the passage of an anti-surge resistor can be further realized, and the heating damage of the anti-surge resistor caused by overlarge current can be effectively avoided; in addition, the hardware circuit structure is arranged to control the short circuit or the passage of the anti-surge resistor, so that the timeliness of the protection of the power supply protection circuit can be ensured, and the reliability of the power supply protection circuit is further improved; meanwhile, the hysteresis comparison module outputs level signals according to two different preset voltages, so that the hysteresis control effect can be achieved, the switching-on or switching-off of the switching module is prevented under the condition of normal fluctuation of the power supply voltage of the third capacitor, the switching-on or switching-off of the switching module is prevented from being sensitive, and the reliability of the power supply protection circuit is further improved.

It will be understood that equivalents and modifications will occur to those skilled in the art in light of the present utility model and their spirit, and all such modifications and substitutions are intended to be included within the scope of the present utility model as defined in the following claims.

Claims

1. A power protection circuit connected with a rectifying and filtering circuit, the rectifying and filtering circuit being configured to output a power supply voltage, the rectifying and filtering circuit including an anti-surge resistor, the power protection circuit comprising:

the hysteresis comparison module is connected with the rectification filter circuit, the input end of the hysteresis comparison module is used for inputting a reference voltage and a sampling voltage based on the power supply voltage, and the output end of the hysteresis comparison module is used for outputting a driving voltage;

the switch module is connected with the output end of the hysteresis comparison module, the switch module is connected with the anti-surge resistor in parallel, and the driving voltage is used for driving the switch module to be turned on or turned off.

2. The power protection circuit of claim 1, wherein the hysteresis comparison module comprises:

the voltage dividing resistor group is connected with the rectifying and filtering circuit, the input end of the voltage dividing resistor group inputs the power supply voltage, and the output end of the voltage dividing resistor group is used for outputting the sampling voltage;

the input end of the hysteresis comparison unit is connected with the output end of the voltage dividing resistor group, the input end of the hysteresis comparison unit inputs the reference voltage and the sampling voltage, and the output end of the hysteresis comparison unit is used for outputting the driving voltage.

3. The power supply protection circuit according to claim 2, wherein the voltage dividing resistor group includes a first resistor, a second resistor, a third resistor, and a fourth resistor, one end of the first resistor is connected to the rectifying filter circuit, the other end of the first resistor is connected to one end of the second resistor, the other end of the second resistor is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor and an input end of the hysteresis comparison unit, and the other end of the fourth resistor is grounded.

4. The power protection circuit of claim 3, wherein the hysteresis comparison unit comprises a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, and a comparator; one end of the fifth resistor is connected with the other end of the third resistor, the other end of the fifth resistor is connected with the normal phase input end of the comparator, one end of the sixth resistor is connected with the normal phase input end of the comparator, the other end of the sixth resistor is connected with the output end of the comparator, one end of the seventh resistor and one end of the eighth resistor are both connected with the reverse phase input end of the comparator, the other end of the seventh resistor is connected with electricity, the other end of the eighth resistor is grounded, and the output end of the comparator is connected with the switch module.

5. The power protection circuit according to claim 4, wherein the switching module comprises a switching tube, a ninth resistor and a relay, a first end of the switching tube is connected with an output end of the comparator, a second end of the switching tube is grounded, a third end of the switching tube is connected with a 1 st pin of the relay, a 2 nd pin of the relay is connected with electricity through the ninth resistor, a 3 rd pin of the relay is connected with one end of the anti-surge resistor, and a 4 th pin of the relay is connected with the other end of the anti-surge resistor.

6. A power supply circuit comprising a rectifying and filtering circuit and a power supply protection circuit according to any one of claims 1 to 5; the rectification filter circuit comprises an anti-surge resistor, and is connected with the power supply protection circuit and used for outputting power supply voltage; the power supply protection circuit is connected with the anti-surge resistor in parallel, and is used for being conducted or disconnected according to the power supply voltage.

7. The power circuit of claim 6, wherein the rectifier filter circuit further comprises an EMI filter module and a rectifier filter module, the EMI filter module being coupled to the anti-surge resistor, the rectifier filter module being coupled to the EMI filter module and the power protection circuit.

8. The power circuit of claim 7, wherein the EMI filter module comprises a first capacitor, a second capacitor, a first inductance, and a second inductance; the one end of first electric capacity and the 3 rd foot of first inductance are connected with the zero line, the other end of first electric capacity and the one end of second inductance are connected with the live wire, the other end of second inductance with anti-surge resistance's one end is connected, the 4 th foot of first inductance with anti-surge resistance's the other end is connected, the 2 nd foot of first inductance with the one end of second electric capacity with rectifying and filtering module connects, the 1 st foot of first inductance with the other end of second electric capacity with rectifying and filtering module connects.

9. A circuit board comprising the power supply circuit of any one of claims 6-8 thereon.

10. An air conditioner comprising the circuit board of claim 9.