CN208571914U - Overvoltage crowbar and switching power circuit - Google Patents

Abstract

The utility model relates to electronic circuit technology fields; disclose a kind of overvoltage crowbar and switching power circuit; wherein, overvoltage crowbar is with the voltage input end connecting for the voltage output end with switching power circuit and the pressure feedback port connecting for the feedback reception end with switching power circuit；Overvoltage crowbar includes voltage sampling unit, pressure stabilizing standard, optocoupler and voltage-stabiliser tube；The reference pole of pressure stabilizing standard connects voltage input end, the plus earth of pressure stabilizing standard by voltage sampling unit；Optocoupler includes light emitting diode and phototriode, and the anode of light emitting diode connects voltage input end, the cathode of the cathode connection pressure stabilizing standard of light emitting diode, and the collector of phototriode connects pressure feedback port, the emitter ground connection of phototriode；The cathode of voltage-stabiliser tube is connect with the cathode of pressure stabilizing standard, the plus earth of voltage-stabiliser tube.The utility model reduces the use of some components, simplifies circuit structure, saves cost.

Description

Overvoltage crowbar and switching power circuit

Technical field

The utility model relates to electronic circuit technology fields, more particularly to a kind of overvoltage crowbar and switch power supply Road.

Background technique

It generally all include voltage feedback circuit and overvoltage crowbar, electricity in switching power circuit more commonly used at present Pressure feed circuit is used for the output voltage of detection switch power circuit and feeds back to the control chip in switching power circuit, controls Chip changes output duty cycle so as to adjust the output voltage of switching power circuit, stablizes it in a fixed value.Over-voltage is protected Protection circuit is also excess voltage protection, is for making power supply disconnect or make when voltage is more than scheduled maximum value (over-voltage) A kind of protection circuit that controlled device voltage reduces.

In the prior art, voltage feedback circuit and overvoltage crowbar work independently from each other, since this mode uses Component and lead it is more, therefore lead to increased costs.

Utility model content

The purpose of the utility model embodiment is to provide a kind of overvoltage crowbar and switching power circuit, can be in reality Under the premise of existing over-voltage protecting function and Voltage Feedback function, the use of some components is reduced, to simplify circuit structure, thus Save cost.

In order to solve the above-mentioned technical problem, the utility model embodiment provides a kind of overvoltage crowbar, and the over-voltage is protected Protection circuit has the voltage input end connecting for the voltage output end with switching power circuit and is used for and switch power supply The pressure feedback port of the feedback reception end connection on road；The overvoltage crowbar includes voltage sampling unit, pressure stabilizing standard, light Coupling and voltage-stabiliser tube；

The reference pole of the pressure stabilizing standard connects the voltage input end, the pressure stabilizing by the voltage sampling unit The plus earth of standard；The optocoupler includes light emitting diode and phototriode, the anode connection of the light emitting diode The voltage input end, the cathode of the light emitting diode connect the cathode of the pressure stabilizing standard, the phototriode Collector connects the pressure feedback port, the emitter ground connection of the phototriode；The cathode of the voltage-stabiliser tube and described steady Press the cathode connection of standard, the plus earth of the voltage-stabiliser tube.

Preferably, the overvoltage crowbar further includes first resistor, and the cathode of the voltage-stabiliser tube passes through described First resistor is connect with the cathode of the pressure stabilizing standard.

Preferably, the overvoltage crowbar further includes second resistance, and the anode of the light emitting diode passes through The second resistance connects the voltage input end.

Preferably, the overvoltage crowbar further includes 3rd resistor, the 3rd resistor and described luminous two Pole pipe is in parallel.

Preferably, the voltage sampling unit includes the 4th resistance and the 5th resistance, the pressure stabilizing standard The voltage input end is connected by the 4th resistance with reference to pole, the reference pole of the pressure stabilizing standard also passes through the described 5th Resistance eutral grounding.

Preferably, the overvoltage crowbar further includes first capacitor and the 6th resistance, the first capacitor One end is connect with the cathode of the pressure stabilizing standard, and the other end of the first capacitor passes through the 6th resistance and the pressure stabilizing The reference pole of standard connects.

Preferably, the overvoltage crowbar further includes the second capacitor, one end of second capacitor with it is described The cathode of pressure stabilizing standard connects, and the other end of second capacitor is connect with the reference pole of the pressure stabilizing standard.

In order to solve identical technical problem, the utility model embodiment also provides a kind of switching power circuit, including control Molding block, power module and the overvoltage crowbar, the control module are connect with the power module；The power mould Block is equipped with voltage output end, and the voltage output end is connect with the voltage input end；The control module has feedback reception End, the pressure feedback port are connect with the feedback reception end.

Preferably, the control module includes control chip, and the power module includes transformer, the transformation Device includes main winding and auxiliary winding, and the feedback reception end of the control chip is the feedback reception end of the control module, described The signal output end of control chip is connect with the main winding, and the auxiliary winding is connect with the voltage output end.

Preferably, the control chip is pwm chip, and the feedback reception end of the pwm chip is The feedback reception end of the control chip, the signal output end of the pwm chip are the signal output of the control chip End.

The utility model embodiment provides a kind of overvoltage crowbar and switching power circuit, wherein overvoltage crowbar It is connect by the cathode of voltage-stabiliser tube with the cathode of pressure stabilizing standard, the plus earth of voltage-stabiliser tube, so that working as switching power circuit Output voltage it is excessive when, be connected by voltage-stabiliser tube, so that the electric current of optocoupler increases, so that the collection of phototriode is penetrated Pole dynamic electric resistor becomes smaller, and is lower so that the collection of phototriode penetrates voltage across poles, so that the voltage at feedback reception end is dragged down, So that switching power circuit reduces duty ratio, the final output voltage for reducing switching power circuit, to realize overvoltage protection function Energy；In addition, acquiring Switching Power Supply by voltage sampling unit when in the normal range voltage fluctuation occurs for switching power circuit The output voltage of circuit is simultaneously exported to pressure stabilizing standard, so that the voltage tune that pressure stabilizing standard is acquired according to voltage sampling unit Voltage between its whole cathode and anode to change the size of current of optocoupler, and then changes the voltage at feedback reception end, so that It obtains switching power circuit and changes its output voltage, to realize Voltage Feedback function；Due to the over-voltage of the utility model embodiment It protects circuit by over-voltage protecting function and the fusion of Voltage Feedback function in the same circuit, therefore is realizing over-voltage protecting function Under the premise of Voltage Feedback function, reduce the use of some components, simplify circuit structure, to save cost.

Detailed description of the invention

Fig. 1 is the circuit diagram of the overvoltage crowbar in the utility model embodiment；

Fig. 2 is the circuit diagram of the switching power circuit in the utility model embodiment；

Specific embodiment

The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without creative efforts Every other embodiment obtained, fall within the protection scope of the utility model.

Referring to figs. 1 and 2, a kind of overvoltage crowbar 11 of the preferred embodiment in the utility model, the over-voltage are protected Protection circuit 11 have for the voltage input end V1 connecting of the voltage output end VOUT1 with switching power circuit and for open The pressure feedback port V2 of the feedback reception end COMP connection of powered-down source circuit；The overvoltage crowbar 11 includes voltage sample list Member, pressure stabilizing standard UB102, optocoupler and voltage-stabiliser tube ZD1；

The reference pole of the pressure stabilizing standard UB102 connects the voltage input end V1 by the voltage sampling unit, The plus earth of the pressure stabilizing standard UB102；The optocoupler includes LED P CB101A and phototriode The anode of PCB101B, the LED P CB101A connect the voltage input end V1, the LED P CB101A Cathode connect the cathode of the pressure stabilizing standard UB102, the collector of the phototriode PCB101B connects the voltage The emitter of feedback end V2, the phototriode PCB101B are grounded；The cathode of the voltage-stabiliser tube ZD1 and the pressure stabilizing benchmark The cathode of device UB102 connects, the plus earth of the voltage-stabiliser tube ZD1.

In the utility model embodiment, it is connect by the cathode of voltage-stabiliser tube ZD1 with the cathode of pressure stabilizing standard UB102, The plus earth of voltage-stabiliser tube ZD1, so that be connected when the output voltage of switching power circuit is excessive by voltage-stabiliser tube ZD1, with So that the electric current of optocoupler increases, so that the collection emitter-base bandgap grading dynamic electric resistor of phototriode PCB101B becomes smaller, so that photosensitive The collection of triode PCB101B penetrates voltage across poles and is lower, so that the voltage of feedback reception end COMP is dragged down, so that switching power circuit Reduce duty ratio, the final output voltage for reducing switching power circuit, to realize over-voltage protecting function；In addition, when switch electricity When voltage fluctuation occurs in the normal range for source circuit, the output voltage of switching power circuit is acquired simultaneously by voltage sampling unit Output is to pressure stabilizing standard UB102, so that pressure stabilizing standard UB102 adjusts its yin according to the voltage that voltage sampling unit acquires Voltage between pole and anode to change the size of current of optocoupler, and then changes the voltage of feedback reception end COMP, so that Switching power circuit changes its output voltage, to realize Voltage Feedback function；Since the over-voltage of the utility model embodiment is protected Protection circuit 11 merges over-voltage protecting function and Voltage Feedback function in the same circuit, therefore is realizing over-voltage protecting function Under the premise of Voltage Feedback function, reduce the use of some components, simplify circuit structure, to save cost.

Referring to figs. 1 and 2, the overvoltage crowbar 11 in order to protect the voltage-stabiliser tube ZD1, in the present embodiment It further include first resistor R1, the cathode of the voltage-stabiliser tube ZD1 passes through the first resistor R1's and pressure stabilizing standard UB102 Cathode connection.The first resistor R1 is used for current limliting, to avoid the voltage-stabiliser tube ZD1 is damaged when electric current is excessive, to protect The voltage-stabiliser tube ZD1.

Referring to figs. 1 and 2, in order to protect the LED P CB101A, the over-voltage in the present embodiment is protected Protection circuit 11 further includes second resistance R2, and the anode of the LED P CB101A passes through second resistance R2 connection institute State voltage input end V1.The second resistance R2 is divided for current limliting, to avoid the LED P CB101A because being more than volume Determine power and damage, to protect the LED P CB101A.

Referring to figs. 1 and 2, in order to ensure the pressure stabilizing standard UB102 can be worked normally, in the present embodiment The overvoltage crowbar 11 further includes 3rd resistor R3, and the 3rd resistor R3 is in parallel with the LED P CB101A. The 3rd resistor R3 is used to provide extracurrent for the pressure stabilizing standard UB102, so that it is guaranteed that the pressure stabilizing standard UB102 can be worked normally.

Referring to figs. 1 and 2, in order to realize that the output voltage by switching power circuit feeds back to the pressure stabilizing standard The reference pole of UB102, the voltage sampling unit in the present embodiment include the 4th resistance R4 and the 5th resistance R5, the pressure stabilizing The reference pole of standard UB102 passes through the 4th resistance R4 connection voltage input end V1, the pressure stabilizing standard UB102 Reference pole also pass through the 5th resistance R5 ground connection.By the way that the concatenated 4th resistance R4 and the 5th resistance R5 is connected It connects in voltage input end V1, and the reference pole of the pressure stabilizing standard UB102 is made to be connected to the 4th resistance R4 and described Between 5th resistance R5, to realize the ginseng that the output voltage of switching power circuit is fed back to the pressure stabilizing standard UB102 Examine pole.

Referring to figs. 1 and 2, the overvoltage crowbar 11 further includes first capacitor C1 and the 6th resistance R6, described One end of first capacitor C1 is connect with the cathode of the pressure stabilizing standard UB102, and the other end of the first capacitor C1 passes through institute The 6th resistance R6 is stated to connect with the reference pole of the pressure stabilizing standard UB102.Pass through the first capacitor C1 and the 6th electricity It hinders R6 and forms loop compensation circuit, be used for adjustment loop response speed.

In conjunction with shown in Fig. 1 to Fig. 2, the overvoltage crowbar 11 further includes the second capacitor C2, the second capacitor C2's One end is connect with the cathode of the pressure stabilizing standard UB102, the other end and the pressure stabilizing standard of the second capacitor C2 The reference pole of UB102 connects.Loop compensation circuit is formed by the second capacitor C2, is used for adjustment loop response speed, or Person forms loop compensation circuit by the second capacitor C2, the first capacitor C1 and the 6th resistance R6, for adjusting Loop response speed.

It is done in detail below with reference to working principle of the Fig. 1 and Fig. 2 to overvoltage crowbar 11 provided by the embodiment of the utility model Thin description:

When the output voltage of switching power circuit excessive (over-voltage), it is steady that the voltage at the both ends the voltage-stabiliser tube ZD1 is greater than it Pressure value, the voltage-stabiliser tube ZD1 conducting, so that the electricity of the LED P CB101A and the phototriode PCB101B Stream increases, so that the collection emitter-base bandgap grading dynamic electric resistor of the phototriode PCB101B becomes smaller, so that photosensitive three pole The collection of pipe PCB101B penetrates voltage across poles and is lower, so that the voltage of the feedback reception end COMP is dragged down, so that switching power circuit Reduce duty ratio, the final output voltage for reducing switching power circuit, and the output voltage stabilization of switching power circuit is made to exist The range of setting, to realize over-voltage protecting function.

When the output voltage of switching power circuit increases (non-over-voltage) in the normal range, the both ends the voltage-stabiliser tube ZD1 Voltage be less than its pressure stabilizing value, the voltage-stabiliser tube ZD1 is not turned on, the output of the voltage sampling unit acquisition switching power circuit Voltage is simultaneously exported to the pressure stabilizing standard UB102, so that the pressure stabilizing standard UB102 adopts the voltage sampling unit The voltage of collection is compared with its internal reference voltage, when the reference pole of the pressure stabilizing standard UB102 voltage greatly in the inner When portion's reference voltage, so that the voltage between the cathode and anode of the pressure stabilizing standard UB102 reduces, to increase the hair The electric current of optical diode PCB101A and the phototriode PCB101B, so that the collection of the phototriode PCB101B is penetrated Pole dynamic electric resistor becomes smaller, so that the collection of the phototriode PCB101B penetrates voltage across poles and is lower, to drag down described anti- The voltage of receiving end COMP is presented, so that switching power circuit reduces duty ratio, the final output voltage for reducing switching power circuit. Conversely, may make the switch electricity when the voltage of the reference pole of the pressure stabilizing standard UB102 is less than its internal reference voltage The output voltage of source circuit increases, to realize Voltage Feedback function.

In order to solve identical technical problem, the utility model embodiment also provides a kind of switching power circuit, including control Molding block 12, power module 13 and the overvoltage crowbar 11, the control module 12 are connect with the power module 13； The power module 13 is equipped with voltage output end, and the voltage output end is connect with the voltage input end V1；The control mould There is block 12 feedback reception end COMP, the pressure feedback port V2 to connect with the feedback reception end COMP.

It is shown in Figure 2, in order to realize the connection of the control module 12 and the power module 13, so that the control Molding block 12 controls the output voltage of the power module 13, and the control module 12 in the present embodiment includes control chip, The power module 13 includes transformer TB101, and the transformer TB101 includes main winding and auxiliary winding, the control chip Feedback reception end COMP be the control module 12 feedback reception end COMP, it is described control chip signal output end GATE It is connect with the main winding, the auxiliary winding is connect with the voltage output end.

The control chip shown in Figure 2, for the ease of adjusting the duty ratio of the control chip, in the present embodiment Preferably pwm chip, the feedback reception end COMP of the pwm chip are the feedback reception end of the control chip COMP, the signal output end GATE of the pwm chip are the signal output end GATE of the control chip.

It is described in detail below with reference to working principle of the Fig. 2 to switching power circuit provided by the embodiment of the utility model:

When increasing (non-over-voltage) when the output voltage of switching power circuit excessive (over-voltage) or in the normal range, pass through institute The voltage that overvoltage crowbar 11 drags down the feedback reception end COMP of the pwm chip is stated, to reduce the PWM control core The duty ratio of the output of piece, so that the voltage of the main winding and the auxiliary winding declines, so that the switch is electric The output voltage of source circuit no longer persistently rises, and stablizes in the range of setting.Conversely, when the output electricity of switching power circuit When pressure drop is low, the output voltage of the switching power circuit can be made to increase, so that the output electricity of the switching power circuit Pressure is stablized.

The utility model embodiment provides a kind of overvoltage crowbar 11 and switching power circuit, wherein overvoltage protection electricity Road 11 is connect by the cathode of voltage-stabiliser tube ZD1 with the cathode of pressure stabilizing standard UB102, the plus earth of voltage-stabiliser tube ZD1, so that It when the output voltage of switching power circuit is excessive, is connected by voltage-stabiliser tube ZD1, so that the electric current of optocoupler increases, to make The collection emitter-base bandgap grading dynamic electric resistor for obtaining phototriode PCB101B becomes smaller, so that electric between the collection emitter-base bandgap grading of phototriode PCB101B Buckling is low, so that the voltage of feedback reception end COMP is dragged down, so that switching power circuit reduces duty ratio, and it is final to reduce switch electricity The output voltage of source circuit, to realize over-voltage protecting function；In addition, when voltage occurs in the normal range for switching power circuit When fluctuation, the output voltage of switching power circuit is acquired by voltage sampling unit and is exported to pressure stabilizing standard UB102, so that It obtains pressure stabilizing standard UB102 and the voltage between its cathode and anode is adjusted according to the voltage that voltage sampling unit acquires, to change The size of current of darkening coupling, and then change the voltage of feedback reception end COMP, so that switching power circuit changes its output electricity Pressure, to realize Voltage Feedback function；Due to the utility model embodiment overvoltage crowbar 11 by over-voltage protecting function and Voltage Feedback function merges in the same circuit, therefore under the premise of realizing over-voltage protecting function and Voltage Feedback function, The use for reducing some components, simplifies circuit structure, to save cost.Further, since the utility model is implemented The overvoltage crowbar 11 that example provides reduces the use of some components, therefore reduces the difficulty of wiring, reduces simultaneously PCB surface product, improves pcb board utilization rate, reduces the difficulty of design and scheduling and planning, to further save cost.

The above is only the preferred embodiment of the utility model, it is noted that for the common skill of the art For art personnel, without deviating from the technical principle of the utility model, several improvement and replacement can also be made, these change It also should be regarded as the protection scope of the utility model into replacement.

Claims (10)

1. a kind of overvoltage crowbar, which is characterized in that the overvoltage crowbar has for the electricity with switching power circuit The voltage input end of pressure output end connection and the pressure feedback port being connect for the feedback reception end with switching power circuit；Institute Stating overvoltage crowbar includes voltage sampling unit, pressure stabilizing standard, optocoupler and voltage-stabiliser tube；

The reference pole of the pressure stabilizing standard connects the voltage input end, the pressure stabilizing benchmark by the voltage sampling unit The plus earth of device；The optocoupler includes light emitting diode and phototriode, described in the anode connection of the light emitting diode Voltage input end, the cathode of the light emitting diode connect the cathode of the pressure stabilizing standard, the current collection of the phototriode Pole connects the pressure feedback port, the emitter ground connection of the phototriode；The cathode of the voltage-stabiliser tube and the pressure stabilizing base The cathode of quasi- device connects, the plus earth of the voltage-stabiliser tube.

2. overvoltage crowbar as described in claim 1, which is characterized in that the overvoltage crowbar further includes the first electricity Resistance, the cathode of the voltage-stabiliser tube are connect by the first resistor with the cathode of the pressure stabilizing standard.

3. overvoltage crowbar as described in claim 1, which is characterized in that the overvoltage crowbar further includes the second electricity The anode of resistance, the light emitting diode connects the voltage input end by the second resistance.

4. overvoltage crowbar as described in any one of claims 1-3, which is characterized in that the overvoltage crowbar further includes 3rd resistor, the 3rd resistor are in parallel with the light emitting diode.

5. overvoltage crowbar as described in claim 1, which is characterized in that the voltage sampling unit include the 4th resistance and The reference pole of 5th resistance, the pressure stabilizing standard connects the voltage input end, the pressure stabilizing base by the 4th resistance The reference pole of quasi- device also passes through the 5th resistance eutral grounding.

6. overvoltage crowbar as claimed in claim 5, which is characterized in that the overvoltage crowbar further includes first capacitor With the 6th resistance, one end of the first capacitor is connect with the cathode of the pressure stabilizing standard, the other end of the first capacitor It is connect by the 6th resistance with the reference pole of the pressure stabilizing standard.

7. such as overvoltage crowbar described in claim 5 or 6, which is characterized in that the overvoltage crowbar further includes second Capacitor, one end of second capacitor are connect with the cathode of the pressure stabilizing standard, the other end of second capacitor with it is described The reference pole of pressure stabilizing standard connects.

8. a kind of switching power circuit, which is characterized in that including control module, power module and as claim 1-7 is any Overvoltage crowbar described in, the control module are connect with the power module；The power module is equipped with voltage output End, the voltage output end are connect with the voltage input end；The control module has feedback reception end, the Voltage Feedback End is connect with the feedback reception end.

9. switching power circuit as claimed in claim 8, which is characterized in that the control module includes control chip, described Power module includes transformer, and the transformer includes main winding and auxiliary winding, and the feedback reception end of the control chip is institute State the feedback reception end of control module, the signal output end of the control chip is connect with the main winding, the auxiliary winding and The voltage output end connection.

10. switching power circuit as claimed in claim 9, which is characterized in that the control chip is pwm chip, institute The feedback reception end for stating pwm chip is the feedback reception end of the control chip, the signal output of the pwm chip End is the signal output end of the control chip.