CN206321756U - Power failure detection circuit and switching power supply circuit - Google Patents
Power failure detection circuit and switching power supply circuit Download PDFInfo
- Publication number
- CN206321756U CN206321756U CN201621372393.XU CN201621372393U CN206321756U CN 206321756 U CN206321756 U CN 206321756U CN 201621372393 U CN201621372393 U CN 201621372393U CN 206321756 U CN206321756 U CN 206321756U
- Authority
- CN
- China
- Prior art keywords
- resistance
- circuit
- output
- type triode
- electric capacity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 68
- 238000005070 sampling Methods 0.000 claims abstract description 18
- 230000005611 electricity Effects 0.000 claims abstract description 14
- 238000004804 winding Methods 0.000 claims description 26
- 239000004065 semiconductor Substances 0.000 claims description 24
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 230000003287 optical effect Effects 0.000 claims 1
- 230000002093 peripheral effect Effects 0.000 abstract description 2
- 230000008859 change Effects 0.000 description 4
- 238000001914 filtration Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005034 decoration Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
Landscapes
- Dc-Dc Converters (AREA)
Abstract
The utility model discloses a power failure detection circuit, which is provided with an alternating current detection end and a detection signal output end used for being connected with an output enabling end of a PWM control chip in a switch power supply circuit; the power failure detection circuit comprises an alternating current sampling unit, a PNP type triode and a first resistor; the alternating current detection end is connected with the base electrode of the PNP type triode through the alternating current sampling unit, the emitting electrode of the PNP type triode is connected with the direct current power supply connection end, and the collecting electrode of the PNP type triode is grounded through the first resistor; and the collector electrode of the PNP type triode is connected with the detection signal output end. When the power fails, the power failure detection circuit outputs a detection signal to enable the PWM control chip to stop outputting, and further the voltage output of the switching power supply circuit is stopped, and the rapid power failure protection is realized. The utility model discloses still protected a switching power supply circuit, through the peripheral detection circuitry that falls that increases of PWM control chip at switching power supply circuit, realized falling the electricity fast, it is with low costs.
Description
Technical field
The utility model is related to electronic circuit technology field, and in particular to a kind of power-fail detection circuit and switch power supply
Road.
Background technology
In daily life, the situation for occurring power down because of electric network fault happens occasionally, therefore in switching power circuit
Usually need be furnished with power-down protection.At present, generally using with quick power-down protection host chipset into switch
Power circuit, to be protected to electronic circuit, but there is problems with this technical scheme：
1st, cost is added using the chip with quick power-down protection.
If the 2, primary circuit is not required to power-down protection, need to change master chip, this will cause the change of peripheral circuit,
The other functions of switching power circuit are even influenceed, are unfavorable for the standardization of circuit.
Utility model content
The technical problems to be solved in the utility model is to provide a kind of power-fail detection circuit and switching power circuit, can
By increasing power-fail detection circuit on the pwm chip periphery for the switching power circuit for not possessing quick power down function, falling
When power detection circuit detects alternating current power failure, the PWM that power-fail detection circuit transmits power-off signal to switching power circuit is controlled
Chip, and then the output of switching power circuit is turned off, realize quick power down；The utility model need not change switching power circuit
Master chip, the other functions of circuit are not influenceed, are conducive to the standardization of circuit, are reduced cost.
To solve above technical problem, the utility model embodiment provides a kind of power-fail detection circuit, with exchange electric-examination
Survey end and the detection signal output part being connected for the output Enable Pin with the pwm chip in switching power circuit；Institute
Stating power-fail detection circuit includes alternating current sampling unit, PNP type triode and first resistor；The alternating current test side passes through institute
The base stage that alternating current sampling unit is stated with the PNP type triode is connected, the emitter stage and dc source of the PNP type triode
Connection end is connected, and the colelctor electrode of the PNP type triode is grounded by the first resistor；The current collection of the PNP type triode
Pole is connected with the detection signal output part.
Further, the alternating current sampling unit includes second resistance and 3rd resistor；The alternating current test side according to
It is secondary to be grounded by the second resistance, the 3rd resistor；The base stage of the PNP type triode be connected to the second resistance with
The tie point of the 3rd resistor.
Further, the power-fail detection circuit also includes NPN type triode and the 4th resistance；The NPN type triode
Grounded emitter, the base stage of the NPN type triode passes through the 4th resistance and the colelctor electrode of the PNP type triode connects
Connect, the colelctor electrode of the NPN type triode is connected with the base stage of the PNP type triode.
Further, the alternating current test side is zero line connection end or live wire connection end.
In order to reach the utility model identical purpose, the utility model also proposed a kind of switching power circuit.It is described
Switching power circuit has live wire connection end, zero line connection end, the first load connection end, and the switching power circuit includes input
Current rectifying and wave filtering circuit, pwm chip, metal-oxide-semiconductor, transformer, output rectifier and filter, output voltage feedback circuit and on
The power-fail detection circuit stated；
Two alternating voltages of the live wire connection end, the zero line connection end respectively with the input rectifying filter circuit
Input correspondence is connected, the output end of the input rectifying filter circuit and the first end of the first armature winding of the transformer
Connection；The drain electrode of the metal-oxide-semiconductor is connected with the second end of the first armature winding of the transformer, the grid of the metal-oxide-semiconductor with
The signal output part connection of the pwm chip, the source ground of the metal-oxide-semiconductor；The output of the pwm chip is enabled
End is connected with the detection signal output part of the power-fail detection circuit；The output rectifier and filter jumps to the transformer
The first secondary windings two ends；The voltage output end of the output rectifier and filter connects with the described first load connection end
Connect；The input of the output voltage feedback circuit is connected with the voltage output end of the output rectifier and filter, described defeated
The output end for going out voltage feedback circuit is connected with the pressure feedback port of the pwm chip.
Further, the switching power circuit includes the 5th resistance；The source electrode of the metal-oxide-semiconductor passes through the 5th resistance
Ground connection；The current detecting end of the pwm chip is connected with the source electrode of the metal-oxide-semiconductor.
Further, the switching power circuit also includes the 6th resistance and the first electric capacity；The electricity of the pwm chip
Stream test side is connected to the source electrode of the metal-oxide-semiconductor by the 6th resistance；The first end of first electric capacity is controlled with the PWM
The current detecting end connection of coremaking piece；The second end ground connection of first electric capacity.
Further, the output voltage feedback circuit includes photo-coupler, TL431 chips, the 7th resistance, the 8th electricity
Resistance, the 9th resistance and the tenth resistance；The photo-coupler includes light emitting diode and phototriode；The light emitting diode
Anode is connected to the voltage output end of the output rectifier and filter, the moon of the light emitting diode by the 7th resistance
Pole is connected with the negative electrode of the TL431 chips, the plus earth of the TL431 chips；8th resistance and described luminous two
Pole pipe is in parallel；The voltage output end of the output rectifier and filter passes sequentially through the 9th resistance, the tenth resistance and connect
Ground；The reference pole of the TL431 chips is connected to the tie point of the 9th resistance and the tenth resistance；Photosensitive three pole
The colelctor electrode of pipe is connected with the pressure feedback port of the pwm chip, the grounded emitter of the phototriode.
Further, the output voltage feedback circuit also includes the 11st resistance, the second electric capacity and the 3rd electric capacity；It is described
The first end of second electric capacity is connected with the negative electrode of the light emitting diode, and the second end of second electric capacity is connected to the described 9th
The tie point of resistance and the tenth resistance；The first end of 3rd electric capacity passes through the 11st resistance and the TL431
The negative electrode connection of chip, the second end of the 3rd electric capacity is connected to the tie point of the 9th resistance and the tenth resistance.
Further, the switching power circuit also includes the first diode, the 12nd resistance and the 4th electric capacity；Described
The first end of 12 resistance is connected with the live wire connection end or the zero line connection end；Second end of the 12nd resistance with
The negative electrode connection of first diode；The anode of first diode is connect by the second armature winding of the transformer
Ground；The positive pole of 4th electric capacity is connected with the negative electrode of first diode, the negative pole ground connection of the 4th electric capacity；Described
The negative electrode of one diode is connected with the power end of the pwm chip.
Compared to prior art, a kind of beneficial effect of power-fail detection circuit of the present utility model is：The utility model
The detection letter being connected with alternating current test side and for the output Enable Pin with the pwm chip in switching power circuit
Number output end；The power-fail detection circuit includes alternating current sampling unit, PNP type triode and first resistor；The alternating current
Test side is connected by the alternating current sampling unit with the base stage of the PNP type triode, the transmitting of the PNP type triode
Pole is connected with dc source connection end, and the colelctor electrode of the PNP type triode is grounded by the first resistor；The positive-negative-positive
The colelctor electrode of triode is connected with the detection signal output part.By above structure, the utility model can detect exchange
The detection signal for controlling pwm chip signal output is produced during electric power down, pwm chip is stopped output PWM letters
Number, and then the alternation electricity input of the armature winding of transformer first is stopped, realize quick power down.The utility model also provides one kind
Switching power circuit, can be by increasing above-mentioned detection of power loss electricity on the pwm chip periphery for not possessing quick power down function
Road, realizes the quick power down of switching power circuit, reduces cost.
Brief description of the drawings
Fig. 1 is a kind of structural representation for power-fail detection circuit that the utility model embodiment is provided；
Fig. 2 is a kind of structural representation for switching power circuit that the utility model embodiment is provided.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is carried out
Clearly and completely describe, it is clear that described embodiment is only a part of embodiment of the utility model, rather than whole
Embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are not under the premise of creative work is made
The every other embodiment obtained, belongs to the scope of the utility model protection.
Referring to Fig. 1, it is a kind of structural representation of power-fail detection circuit 11 of the utility model embodiment.This practicality
The power-fail detection circuit 11 of new embodiment has alternating current test side and for controlling core with the PWM in switching power circuit
The detection signal output part Vout of the output Enable Pin connection of piece；The power-fail detection circuit 11 includes alternating current sampling unit
101st, PNP type triode Q1 and first resistor R1；The alternating current test side by the alternating current sampling unit 101 with it is described
PNP type triode Q1 base stage connection, the emitter stage of the PNP type triode Q1 is connected with dc source connection end VDD, described
PNP type triode Q1 colelctor electrode is grounded by the first resistor R1；The colelctor electrode of the PNP type triode Q1 and the inspection
Survey signal output part Vout connections.
Further, the alternating current sampling unit 101 includes second resistance R2,3rd resistor R3；The exchange electric-examination
Survey end and pass sequentially through the second resistance R2, the 3rd resistor R3 ground connection；The base stage of the PNP type triode Q1 is connected to institute
State second resistance R2 and the 3rd resistor R3 tie point.The second resistance R2 and 3rd resistor R3 is used for exchange
Electric partial pressure, by the base stage of the control source got to the PNP type triode Q1.
Further, the alternating current sampling unit 101 also includes the 5th electric capacity C5；The 5th electric capacity C5 and described the
Three resistance R3 are in parallel.The 5th electric capacity C5 is used to filter so that be input to the voltage of base stage of the PNP triode Q1 more
It is stable.
The operation principle of the utility model embodiment is as follows：
When the alternating current test side detects alternating current normal work, described in 101 pairs of the alternating current sampling unit
PNP type triode Q1 base-transport high level, ends the PNP type triode Q1, due to the PNP type triode Q1's
Colelctor electrode is grounded by the first resistor R1, and the voltage of the colelctor electrode of the PNP type triode Q1 is pulled low, then the detection
Signal output part Vout exports low level so that the normal output pwm signal of pwm chip is with driving switch power circuit
Normal work.
When the alternating current test side detects alternating current power failure, described 101 pairs of positive-negative-positives of alternating current sampling unit
Triode Q1 base-transport low level, turns on the PNP type triode Q1, the current collection of the PNP type triode Q1 conductings
The voltage of pole is driven high, then the detection signal output part Vout output high level so that the pwm chip stops output
Pwm signal is so that switching power circuit is stopped.
Further, the power-fail detection circuit 11 also includes NPN type triode Q2 and the 4th resistance R4；The NPN type
Triode Q2 grounded emitter, the base stage of the NPN type triode Q2 passes through the 4th resistance R4 and the pole of positive-negative-positive three
Pipe Q1 colelctor electrode connection, the colelctor electrode of the NPN type triode Q2 is connected with the base stage of the PNP type triode Q1.It is described
4th resistance R4 is used to bias.
The operation principle of the NPN type triode Q2 is：When the alternating current test side detects alternating current normal work
When, due to PNP type triode Q1 cut-offs and first resistor R1 ground connection, the electricity of the base stage of the NPN type triode Q2
Pressure is pulled low, the NPN type triode Q2 cut-offs, detection signal output part Vout output low levels；When the exchange electro-detection
When end detects alternating current power failure, due to PNP type triode Q1 conductings, the 4th resistance R4 is the pole of NPN type three
Pipe Q2 base-transport high level, turns on the NPN type triode Q2, and the colelctor electrode output of the NPN type triode Q2 is low
Level, now the voltage of the base stage of the PNP type triode Q1 is pulled low, therefore the power-fail detection circuit 11 is locked, institute
State PNP type triode Q1 to tend to remain on, detection signal output part Vout is persistently exported high level.Therefore, even if exchange
After electricity recovers normal, the pwm chip also will not again output pwm signal, it is necessary to by dc source connection end VDD voltage
Being pulled to low level can just unlock state.
Further, the alternating current test side is zero line connection end or live wire connection end.
Referring to Fig. 2, it is a kind of structural representation for switching power circuit that the utility model embodiment is provided.This reality
There is live wire connection end L, zero line connection end N, the first load connection end with a kind of switching power circuit of new embodiment, it is described
Switching power circuit includes input rectifying filter circuit 21, pwm chip U1, metal-oxide-semiconductor FET, transformer T1, output rectification filter
Wave circuit 22, output voltage feedback circuit 23 and above-mentioned power-fail detection circuit 11；
The live wire connection end L, the zero line connection end N are exchanged with two of the input rectifying filter circuit 21 respectively
Voltage input end correspondence is connected, the output end of the input rectifying filter circuit 21 and the first armature winding of the transformer T1
First end connection；The drain electrode of the metal-oxide-semiconductor FET is connected with the second end of the first armature winding of the transformer T1, described
Metal-oxide-semiconductor FET grid is connected with the signal output part GATE of the pwm chip U1, the source ground of the metal-oxide-semiconductor FET；
The output Enable Pin FB of the pwm chip U1 is connected with the detection signal output part Vout of the power-fail detection circuit 11；
The earth terminal GND ground connection of the pwm chip U1, pwm chip U1 power end VCC and dc source connection end VDD
Connection；The output rectifier and filter 22 jumps to the two ends of the first secondary windings of the transformer T1；The output is whole
The voltage output end for flowing filter circuit 22 is connected with the described first load connection end；The input of the output voltage feedback circuit 23
End is connected with the voltage output end of the output rectifier and filter 22, the output end of the output voltage feedback circuit 23 and institute
State pwm chip U1 pressure feedback port COMP connections.
Wherein, in the present embodiment, the alternating current test side of the power-fail detection circuit 11 is the zero line connection end N.
Further, the switching power circuit includes the 5th resistance R5；The source electrode of the metal-oxide-semiconductor FET passes through described
Five resistance R5 are grounded；The current detecting end CS of the pwm chip U1 is connected with the source electrode of the metal-oxide-semiconductor FET.Described 5th
Resistance R5 is used for current limliting, and the current detecting end CS of the pwm chip U1 is used for the first primary for detecting the transformer T1
Winding current, when detect electric current it is excessive when, the signal output part GATE of the pwm chip U1 exports described for turning off
Metal-oxide-semiconductor FET signal, turns off the metal-oxide-semiconductor FET, realizes overcurrent protection.
Further, the switching power circuit also includes the 6th resistance R6 and the first electric capacity C1；The pwm chip
U1 current detecting end CS is connected to the source electrode of the metal-oxide-semiconductor FET by the 6th resistance R6；The of the first electric capacity C1
One end is connected with the current detecting end CS of the pwm chip U1；The second end ground connection of the first electric capacity C1.Described 6th
Resistance R6 and the first electric capacity C1 constitutes RC filter circuits, improves the reliability of overcurrent protection.
Further, the output voltage feedback circuit 23 includes photo-coupler, TL431 chips U2, the 7th resistance R7, the
Eight resistance R8, the 9th resistance R9 and the tenth resistance R10；The photo-coupler includes LED and phototriode Q3；
The voltage that the anode of the LED is connected to the output rectifier and filter 22 by the 7th resistance R7 is defeated
Go out end, the negative electrode of the LED is connected with the negative electrode of the TL431 chips U2, the anode of the TL431 chips U2
Ground connection；The 8th resistance R8 is in parallel with the LED；The voltage output end of the output rectifier and filter 22
Pass sequentially through the 9th resistance R9, the tenth resistance R10 ground connection；The reference pole of the TL431 chips U2 is connected to described
9th resistance R9 and the tenth resistance R10 tie point；The colelctor electrode of the phototriode Q3 and the pwm chip
U1 pressure feedback port COMP connections, the grounded emitter of the phototriode Q3.The 9th resistance R9 and the described tenth
Resistance R10 constitutes bleeder circuit, the control source got to the reference pole of the TL431 chips U2；The TL431 chips U2 is used
In the voltage change for the voltage output end for detecting the output rectifier and filter 22, when the output rectifier and filter 22
During the voltage rise of voltage output end, negative electrode and the anode short circuit of the TL431 chips U2, by the LED
Minus earth so that the photo-coupler conducting, the output duty cycle reduction of the pwm chip U1 makes the transformer
The voltage of the armature windings of T1 first declines, and then declines the output voltage of switching power circuit；When the output rectification filter
When the voltage of the voltage output end of circuit 22 declines, the photo-coupler is not turned on, the output duty of the pwm chip U1
Than improving, the voltage of the armature windings of transformer T1 first is raised, and then raises the output voltage of switching power circuit,
So as to form negative voltage feedback so that the voltage stabilization of voltage output end；The 8th resistance R8 is used to provide partially for TL431
Put, when the photo-coupler is not turned on, the TL431 chips U2 is powered by the 8th resistance R8.
Further, the output voltage feedback circuit 23 also includes the 11st resistance R11, the second electric capacity C2 and the 3rd electricity
Hold C3；The first end of the second electric capacity C2 is connected with the negative electrode of the LED, and the second of the second electric capacity C2
End is connected to the 9th resistance R9 and the tenth resistance R10 tie point；The first end of the 3rd electric capacity C3 passes through institute
The negative electrode that the 11st resistance R11 is stated with the TL431 chips U2 is connected, and the second end of the 3rd electric capacity C3 is connected to described
Nine resistance R9 and the tenth resistance R10 tie point.The 11st resistance R11, the second electric capacity C2 and the described 3rd
Electric capacity C3 constitutes loop compensation circuit, for adjustment loop response speed.
Further, the switching power circuit also includes the first diode D1, the 12nd resistance R12 and the 4th electric capacity
C4；The first end of the 12nd resistance R12 is connected with the live wire connection end L or described zero lines connection end N；Described 12nd
Resistance R12 the second end is connected with the negative electrode of the first diode D1；The anode of the first diode D1 is become by described
Depressor T1 the second armature winding ground connection；The positive pole of the 4th electric capacity C4 is connected with the negative electrode of the first diode D1, institute
State the 4th electric capacity C4 negative pole ground connection；The negative electrode of the first diode D1 connects with the power end VCC of the pwm chip U1
Connect.The 12nd resistance R12 is used for partial pressure, the first diode D1, the 4th electric capacity C4 and the transformer T1's
Second armature winding constitutes current rectifying and wave filtering circuit, direct current is provided for the pwm chip U1, due to first diode
D1, the 12nd resistance R12, the circuit of the 4th electric capacity C4 and the transformer T1 the second armature winding composition lack
Weary power supply, thus the live wire connection end L or described zero lines connection end N need to be connected, provide startup voltage for circuit.Wherein, exist
In the present embodiment, the first end of the 12nd resistance R12 is connected with the live wire connection end L.
Further, the negative electrode of the first diode D1 and the dc source connection end in the power-fail detection circuit 11
VDD connections.I.e. described first diode D1, the 4th electric capacity C4 and the transformer T1 the second armature winding composition rectification
Filter circuit, while being that the pwm chip U1 and the power-fail detection circuit 11 are powered.
Further, the input rectifying filter circuit 21 includes rectifier bridge BR and the 6th electric capacity C6；The rectifier bridge BR
Including first input end, the second input, the first output end and the second output end；The first input end and the described second input
Hold two ac voltage inputs for the input rectifying filter circuit 21；First output end and second output end
Between pass through the 6th electric capacity C6 connections；First output end is the output end of the input rectifying filter circuit 21；Institute
State the second output head grounding.The alternating current of input is by exporting stable direct current after the rectifier bridge BR and the 6th electric capacity C6
Electricity.
Further, the output rectifier and filter 22 includes the second diode D2 and the 7th electric capacity C7；Described second
Diode D2 anode is connected with the first end of the first secondary windings of the transformer T1, the negative electrode of the second diode D2
It is connected with the positive pole of the 7th electric capacity C7；The negative pole of the 7th electric capacity C7 and the first secondary windings of the transformer T1
Second end is connected, the negative pole ground connection of the 7th electric capacity C7；The second diode D2 and the 7th electric capacity C7 tie point
It is connected with the described first load connection end.The second diode D2 is used for rectification, and the 7th electric capacity C7 is used to filter.
Further, the switching power circuit also has the second load connection end；The switching power circuit also includes
3rd diode D3 and the 8th electric capacity C8；The anode of the 3rd diode D3 and the second subprime winding of the transformer T1
First end is connected, and the negative electrode of the 3rd diode D3 is connected with the positive pole of the 8th electric capacity C8；The 8th electric capacity C8's
Negative pole is connected with the second end of the second subprime winding of the transformer T1, the negative pole ground connection of the 8th electric capacity C8；Described
Three diode D3 are connected with the tie point of the 8th electric capacity C8 with the described second load connection end.The 3rd diode D3,
The 8th electric capacity C8 and transformer T1 second subprime winding composition current rectifying and wave filtering circuit, exporting galvanic current is
Load supplying.
The operation principle of the utility model embodiment is as follows：
In normal operation, the power-fail detection circuit 11 exports low level to the defeated of the pwm chip U1
Go out Enable Pin FB, the pwm chip U1 output pwm signals control the metal-oxide-semiconductor FET switch, and alternating current is by described defeated
Smooth direct current output is obtained after entering current rectifying and wave filtering circuit 21, the transformer T1 and the output rectifier and filter 22
Electricity, is load supplying；When output voltage changes, the PWM is adjusted by the output voltage feedback circuit 23 and controlled
Chip U1 output duty cycle, so as to adjust the voltage of the armature windings of transformer T1 first, and then stablizes the switch electricity
The output voltage of source circuit；
When the power-fail detection circuit 11 detects alternating current power failure, 11 pairs of the power-fail detection circuit PWM controls
Coremaking piece U1 output Enable Pin FB transmission high level, stops the pwm signal output of the pwm chip U1, and then realizes
The quick power down of the switching power circuit.
Compared to prior art, a kind of beneficial effect of power-fail detection circuit of the present utility model is：The utility model
The detection letter being connected with alternating current test side and for the output Enable Pin with the pwm chip in switching power circuit
Number output end；The power-fail detection circuit includes alternating current sampling unit, PNP type triode and first resistor；The alternating current
Test side is connected by the alternating current sampling unit with the base stage of the PNP type triode, the transmitting of the PNP type triode
Pole is connected with dc source, and the colelctor electrode of the PNP type triode is grounded by the first resistor；The PNP type triode
Colelctor electrode with it is described detection signal output part be connected.By above structure, the utility model can detect alternating current power failure
When produce detection signal for controlling pwm chip signal output, pwm chip is stopped output pwm signal, and then
The alternation electricity input of the armature winding of transformer first is stopped, quick power down is realized.The utility model also provides a kind of switch electricity
Source circuit, can be realized by increasing above-mentioned power-fail detection circuit on the pwm chip periphery for not possessing quick power down function
The quick power down of switching power circuit, reduces cost.
The above is preferred embodiment of the present utility model, it is noted that for the ordinary skill of the art
For personnel, on the premise of the utility model principle is not departed from, some improvements and modifications can also be made, these improve and moistened
Decorations are also considered as protection domain of the present utility model.
Claims (10)
1. a kind of power-fail detection circuit, it is characterised in that with alternating current test side and for in switching power circuit
The detection signal output part of the output Enable Pin connection of pwm chip；It is single that the power-fail detection circuit includes alternating current sampling
Member, PNP type triode and first resistor；The alternating current test side passes through the alternating current sampling unit and the positive-negative-positive three
The base stage connection of pole pipe, the emitter stage of the PNP type triode is connected with dc source connection end, the PNP type triode
Colelctor electrode is grounded by the first resistor；The colelctor electrode of the PNP type triode is connected with the detection signal output part.
2. power-fail detection circuit as claimed in claim 1, it is characterised in that the alternating current sampling unit includes second resistance
With 3rd resistor；The alternating current test side passes sequentially through the second resistance, 3rd resistor ground connection；The positive-negative-positive three
The base stage of pole pipe is connected to the tie point of the second resistance and the 3rd resistor.
3. power-fail detection circuit as claimed in claim 1, it is characterised in that the power-fail detection circuit also includes NPN type three
Pole pipe and the 4th resistance；The grounded emitter of the NPN type triode, the base stage of the NPN type triode passes through the described 4th
Resistance is connected with the colelctor electrode of the PNP type triode, the colelctor electrode of the NPN type triode and the PNP type triode
Base stage is connected.
4. power-fail detection circuit as claimed in claim 1, it is characterised in that the alternating current test side be zero line connection end or
Live wire connection end.
5. a kind of switching power circuit, it is characterised in that with live wire connection end, zero line connection end, the first load connection end, institute
State switching power circuit including input rectifying filter circuit, pwm chip, metal-oxide-semiconductor, transformer, output rectifier and filter,
Output voltage feedback circuit and the power-fail detection circuit as described in any one of Claims 1-4；
The live wire connection end, the zero line connection end are inputted with two alternating voltages of the input rectifying filter circuit respectively
End correspondence connection, the output end of the input rectifying filter circuit and the first end of the first armature winding of the transformer connect
Connect；The drain electrode of the metal-oxide-semiconductor is connected with the second end of the first armature winding of the transformer, the grid of the metal-oxide-semiconductor and institute
State the signal output part connection of pwm chip, the source ground of the metal-oxide-semiconductor；The output Enable Pin of the pwm chip
It is connected with the detection signal output part of the power-fail detection circuit；The output rectifier and filter jumps to the transformer
The two ends of first secondary windings；The voltage output end of the output rectifier and filter is connected with the described first load connection end；
The input of the output voltage feedback circuit is connected with the voltage output end of the output rectifier and filter, the output electricity
The output end of pressure feedback circuit is connected with the pressure feedback port of the pwm chip.
6. switching power circuit as claimed in claim 5, it is characterised in that the switching power circuit includes the 5th resistance；
The source electrode of the metal-oxide-semiconductor passes through the 5th resistance eutral grounding；The current detecting end of the pwm chip and the metal-oxide-semiconductor
Source electrode is connected.
7. switching power circuit as claimed in claim 6, it is characterised in that the switching power circuit also includes the 6th resistance
With the first electric capacity；The current detecting end of the pwm chip is connected to the source electrode of the metal-oxide-semiconductor by the 6th resistance；
The first end of first electric capacity is connected with the current detecting end of the pwm chip；Second termination of first electric capacity
Ground.
8. switching power circuit as claimed in claim 5, it is characterised in that the output voltage feedback circuit includes optical coupling
Device, TL431 chips, the 7th resistance, the 8th resistance, the 9th resistance and the tenth resistance；The photo-coupler includes light emitting diode
With phototriode；The anode of the light emitting diode is connected to the output rectifier and filter by the 7th resistance
Voltage output end, the negative electrode of the light emitting diode is connected with the negative electrode of the TL431 chips, the anode of the TL431 chips
Ground connection；8th resistance is in parallel with the light emitting diode；The voltage output end of the output rectifier and filter leads to successively
Cross the 9th resistance, the tenth resistance eutral grounding；The reference pole of the TL431 chips be connected to the 9th resistance with it is described
The tie point of tenth resistance；The colelctor electrode of the phototriode is connected with the pressure feedback port of the pwm chip, described
The grounded emitter of phototriode.
9. switching power circuit as claimed in claim 8, it is characterised in that the output voltage feedback circuit also includes the tenth
One resistance, the second electric capacity and the 3rd electric capacity；The first end of second electric capacity is connected with the negative electrode of the light emitting diode, described
Second end of the second electric capacity is connected to the tie point of the 9th resistance and the tenth resistance；The first end of 3rd electric capacity
It is connected by the 11st resistance with the negative electrode of the TL431 chips, the second end of the 3rd electric capacity is connected to described
The tie point of nine resistance and the tenth resistance.
10. switching power circuit as claimed in claim 5, it is characterised in that the switching power circuit also includes the one or two
Pole pipe, the 12nd resistance and the 4th electric capacity；The first end of 12nd resistance connects with the live wire connection end or the zero line
End connection is connect, the second end of the 12nd resistance is connected with the negative electrode of first diode；The sun of first diode
Pole is grounded by the second armature winding of the transformer；The positive pole of 4th electric capacity connects with the negative electrode of first diode
Connect, the negative pole ground connection of the 4th electric capacity；The negative electrode of first diode is connected with the power end of the pwm chip.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621372393.XU CN206321756U (en) | 2016-12-14 | 2016-12-14 | Power failure detection circuit and switching power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201621372393.XU CN206321756U (en) | 2016-12-14 | 2016-12-14 | Power failure detection circuit and switching power supply circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN206321756U true CN206321756U (en) | 2017-07-11 |
Family
ID=59268234
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201621372393.XU Active CN206321756U (en) | 2016-12-14 | 2016-12-14 | Power failure detection circuit and switching power supply circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN206321756U (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107290619A (en) * | 2017-08-08 | 2017-10-24 | 广州市三锐电子科技有限公司 | A kind of electrode delamination detects circuit |
| CN107317466A (en) * | 2017-08-29 | 2017-11-03 | 广州市爱浦电子科技有限公司 | The remote control circuit and its Switching Power Supply of a kind of Switching Power Supply |
| CN107492865A (en) * | 2017-08-21 | 2017-12-19 | 深圳创维－Rgb电子有限公司 | A kind of alternating current power failure response circuit and electric equipment |
| CN108630493A (en) * | 2018-07-05 | 2018-10-09 | 蔚来汽车有限公司 | Drive the method and electromagnetic relay driving device, charging pile of electromagnetic relay |
| CN109239445A (en) * | 2018-10-26 | 2019-01-18 | 延锋伟世通电子科技（南京）有限公司 | A kind of power on and off detection circuit of automobile power system |
| CN109324222A (en) * | 2018-11-23 | 2019-02-12 | 江苏林洋能源股份有限公司 | Quick detection of power loss system and method based on reverse exciting topological |
| CN110597665A (en) * | 2019-09-18 | 2019-12-20 | 普联技术有限公司 | Power-down protection device |
| CN110806504A (en) * | 2018-08-03 | 2020-02-18 | 炬芯（珠海）科技有限公司 | Charging power supply detection circuit and detection method |
| CN110992866A (en) * | 2019-12-10 | 2020-04-10 | Tcl华星光电技术有限公司 | Drive circuit of display panel and logic circuit of electronic device |
| CN111077930A (en) * | 2019-12-17 | 2020-04-28 | 太原航空仪表有限公司 | Energy storage circuit power failure monitoring trigger circuit |
| CN111786368A (en) * | 2020-07-13 | 2020-10-16 | 珠海格力智能装备有限公司 | Power-off protection circuit and electronic equipment |
| CN114050626A (en) * | 2021-11-25 | 2022-02-15 | 沃太能源股份有限公司 | Power-down protection circuit and electronic equipment with same |
-
2016
- 2016-12-14 CN CN201621372393.XU patent/CN206321756U/en active Active
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107290619A (en) * | 2017-08-08 | 2017-10-24 | 广州市三锐电子科技有限公司 | A kind of electrode delamination detects circuit |
| CN107290619B (en) * | 2017-08-08 | 2023-09-26 | 广州市三锐电子科技有限公司 | Electrode drop detection circuit |
| CN107492865A (en) * | 2017-08-21 | 2017-12-19 | 深圳创维－Rgb电子有限公司 | A kind of alternating current power failure response circuit and electric equipment |
| CN107317466A (en) * | 2017-08-29 | 2017-11-03 | 广州市爱浦电子科技有限公司 | The remote control circuit and its Switching Power Supply of a kind of Switching Power Supply |
| CN108630493A (en) * | 2018-07-05 | 2018-10-09 | 蔚来汽车有限公司 | Drive the method and electromagnetic relay driving device, charging pile of electromagnetic relay |
| CN110806504B (en) * | 2018-08-03 | 2021-11-02 | 炬芯科技股份有限公司 | Charging power supply detection circuit and detection method |
| CN110806504A (en) * | 2018-08-03 | 2020-02-18 | 炬芯（珠海）科技有限公司 | Charging power supply detection circuit and detection method |
| CN109239445A (en) * | 2018-10-26 | 2019-01-18 | 延锋伟世通电子科技（南京）有限公司 | A kind of power on and off detection circuit of automobile power system |
| CN109239445B (en) * | 2018-10-26 | 2024-05-17 | 延锋伟世通电子科技（南京）有限公司 | Power-on and power-off detection circuit of automobile power supply system |
| CN109324222A (en) * | 2018-11-23 | 2019-02-12 | 江苏林洋能源股份有限公司 | Quick detection of power loss system and method based on reverse exciting topological |
| CN110597665A (en) * | 2019-09-18 | 2019-12-20 | 普联技术有限公司 | Power-down protection device |
| CN110992866A (en) * | 2019-12-10 | 2020-04-10 | Tcl华星光电技术有限公司 | Drive circuit of display panel and logic circuit of electronic device |
| CN111077930A (en) * | 2019-12-17 | 2020-04-28 | 太原航空仪表有限公司 | Energy storage circuit power failure monitoring trigger circuit |
| CN111786368A (en) * | 2020-07-13 | 2020-10-16 | 珠海格力智能装备有限公司 | Power-off protection circuit and electronic equipment |
| CN114050626A (en) * | 2021-11-25 | 2022-02-15 | 沃太能源股份有限公司 | Power-down protection circuit and electronic equipment with same |
| CN114050626B (en) * | 2021-11-25 | 2024-03-08 | 沃太能源股份有限公司 | Power-down protection circuit and electronic equipment with same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN206321756U (en) | Power failure detection circuit and switching power supply circuit | |
| CN103326325A (en) | Short-circuit and low-voltage protective circuit of output of switching power source | |
| CN206321697U (en) | Overvoltage detection circuit and switching power supply circuit | |
| CN110165630A (en) | Air conditioner over-voltage detection circuit, air conditioner electric control gear and air conditioner | |
| CN103166175A (en) | Input overvoltage protection circuit for light-emitting diode (LED) driving power supply | |
| CN103219893A (en) | Switch power supply controller and switch power supply circuit | |
| CN104184111B (en) | Overvoltage protection circuit for high-voltage transmission line ground wire power getting | |
| CN207926438U (en) | DC power supply | |
| CN201887660U (en) | LPC switch power supply circuit and air conditioner with same | |
| CN203632222U (en) | Output short circuit protection circuit of flyback converter | |
| CN103457464A (en) | Current limiting circuit on basis of switching power supplies | |
| CN202111796U (en) | Constant current drive circuit and television set | |
| CN209842877U (en) | Signal lamp fault detection circuit combining signal lamp and signal controller | |
| CN208224355U (en) | A kind of alternating current undervoltage detection warning circuit | |
| CN101895216B (en) | State switching circuit of wide-voltage switch | |
| CN106787048A (en) | Possesses the charger of automatic identification input voltage function | |
| CN203378106U (en) | LED emergency illuminating device | |
| CN203233312U (en) | Switch power supply controller and switch power supply device | |
| CN108990202A (en) | A kind of constant flow high pressure LED drive chip circuit | |
| CN206819200U (en) | Dummy load control circuit | |
| CN203312774U (en) | Short-circuit and low-voltage protective circuit of output of switching power source | |
| CN107197565A (en) | LED drive control circuits | |
| CN209709687U (en) | A kind of power supply unit of M-BUS acquisition concentrator | |
| CN207039476U (en) | Power circuit and television set | |
| CN209250218U (en) | A kind of input undervoltage protection circuit and driving power |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |