CN205070778U - Voltage peak absorption circuit and switching power supply circuit - Google Patents
Voltage peak absorption circuit and switching power supply circuit Download PDFInfo
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- CN205070778U CN205070778U CN201520833537.6U CN201520833537U CN205070778U CN 205070778 U CN205070778 U CN 205070778U CN 201520833537 U CN201520833537 U CN 201520833537U CN 205070778 U CN205070778 U CN 205070778U
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- 238000010521 absorption reaction Methods 0.000 title abstract 3
- 230000005669 field effect Effects 0.000 claims description 12
- 238000001914 filtration Methods 0.000 abstract description 6
- 230000002159 abnormal effect Effects 0.000 abstract description 5
- 238000005070 sampling Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 9
- 230000003071 parasitic effect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012938 design process Methods 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
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Abstract
The utility model discloses a voltage spike absorption circuit, including peak sense terminal, earthing terminal, second switch tube, first electric capacity and first resistance, obtain the voltage spike by the peak sense terminal, pass the control end of second switch tube with the signal of magnitude of voltage rapid change through first electric capacity, control second switch tube switches on, switches on the voltage spike on the peak sense terminal to ground fast, realizes the function of filtering voltage spike, can effectively avoid electronic component to damage, circuit work abnormal scheduling problem. The utility model also discloses an utilize above-mentioned voltage peak absorption circuit's switching power supply circuit, can switch on the voltage peak on switching power supply control chip's the current sampling input to ground fast, can protect the chip, prevent that the chip from triggering by mistake.
Description
Technical field
The utility model relates to electronic technology field, particularly relates to a kind of voltage peak absorbing circuit and switching power circuit.
Background technology
At present in various electronic circuit system, due to the existence of the factor such as switching, static discharge of thunder and lightning, power initiation and shutoff, make the two ends of electronic component can produce the duration short but due to voltage spikes that numerical value is very high.These due to voltage spikes may cause the damage of circuit component, cause circuit board work abnormal.
Typically, in Switching Power Supply, due to the quick on-off of switch, cause voltage and current Rapid Variable Design, the voltage and current of these transitions, by power circuit, parasitic parameter and spuious electromagnetic field couples, surge current and noise can be produced, affect the normal work of circuit.
Common switching power circuit as shown in Figure 1, its operation principle is as follows: power input is connected with the first end of the primary coil of transformer T1, power output end is connected with the secondary coil of transformer T1, the first end of the second end connecting valve pipe Q1 of the primary coil of transformer T1, second end of switching tube Q1 connects the first end of sample circuit Rs, the second end ground connection of sample circuit Rs, the square wave that switching tube Q1 exports by Switching Power Supply control chip controls, Switching Power Supply control chip is by connecting the magnitude of voltage obtained on sample circuit Rs first end, adjustment exports the duty ratio of square wave to reduce or to increase the ON time of switching tube, thus the effective value of adjustment input current, curtage effective value in proof load maintains a stationary value.When switching tube Q1 ends, transformer T1 parasitic capacitance is charged, during switching tube Q1 conducting, transformer T1 parasitic capacitance discharge, therefore in the current branch of the primary coil of transformer T1, switching tube Q1, sample circuit Rs, there will be current spike, thus can due to voltage spikes be produced on the first end of sample circuit Rs.Switching Power Supply control chip is by comparing magnitude of voltage on sample circuit Rs first end and chip internal reference voltage adjusts output, if due to voltage spikes is too high on the first end of sample circuit Rs, Switching Power Supply control chip can be caused to export the signal that switching tube is ended, namely cause chip false triggering.In addition, too high due to voltage spikes is connected to Switching Power Supply control chip also may cause wafer damage.
Utility model content
Technical problem to be solved in the utility model is, a kind of voltage peak absorbing circuit and switching power circuit are provided, avoiding the problems such as the electronic component caused because there is due to voltage spikes in circuit damages, circuit working is abnormal, improving stability, the reliability of circuit working.
In order to solve the problems of the technologies described above, the utility model proposes a kind of voltage peak absorbing circuit, comprise spike test side, earth terminal, second switch pipe, the first electric capacity and the first resistance;
The first end of described second switch pipe connects described spike test side, and the second end of described second switch pipe connects described earth terminal;
The first end of described first electric capacity connects described spike test side, and the second end of described first electric capacity connects the control end of described second switch pipe;
The first end of described first resistance connects the second end of described first electric capacity, and the second end of described first resistance connects described earth terminal.
Preferably, described second switch pipe is NPN type triode, the base stage of described NPN type triode is the control end of described second switch pipe, the first end of the very described second switch pipe of current collection of described NPN type triode, the second end of the very described second switch pipe of transmitting of described NPN type triode.
Meanwhile, the utility model also provides a kind of switching power circuit, comprises power input, power output end, transformer, the first switching tube, Switching Power Supply control chip, sample circuit and above-mentioned voltage peak absorbing circuit;
Described power input is connected with the first end of the primary coil of described transformer, and described power output end is connected with the secondary coil of described transformer;
Second end of the primary coil of described transformer connects the first end of described first switching tube, and the second end of described first switching tube connects the first end of described sample circuit, the second end ground connection of described sample circuit;
Described Switching Power Supply control chip comprises drive singal output and current sample input; The first end of described sample circuit connects described current sample input, and described drive singal output connects the control end of described first switching tube;
The spike test side of described voltage peak absorbing circuit connects described current sample input, the earth terminal ground connection of described voltage peak absorbing circuit.
Preferably, described first switching tube is N-type field effect transistor, the grid of described N-type field effect transistor is the control end of described first switching tube, and the drain electrode of described N-type field effect transistor is the first end of described first switching tube, and the source electrode of described N-type field effect transistor is the second end of described first switching tube.
In a particular embodiment, described sample circuit is single independently resistor, or the connection in series-parallel assembly of multiple resistor.
Further, described switching power circuit also comprises the second resistance; The first end of described sample circuit connects described current sample input, is specially: the first end of described sample circuit connects described current sample input by described second resistance.
Further, described switching power circuit also comprises the 3rd resistance, and the first end of described 3rd resistance connects described current sample input, the second end ground connection of described 3rd resistance.
Further, described switching power circuit also comprises the 4th resistance; Described drive singal output connects the control end of described first switching tube, is specially: described drive singal output connects the control end of described first switching tube by described 4th resistance.
Implement the utility model, there is following beneficial effect:
The voltage peak absorbing circuit that the utility model provides, due to voltage spikes is obtained by spike test side, by electric capacity, fast-changing for magnitude of voltage signal is passed to switching tube, the conducting of control switch pipe, by the due to voltage spikes fast conducting on spike test side to ground, realize the function of filtering due to voltage spikes, effectively can avoid the problems such as electronic component damages, circuit working is abnormal.
The switching power circuit that the utility model provides, obtains the magnitude of voltage on sample circuit first end by Switching Power Supply control chip, adjusts the time scale of the first switching tube conducting and cut-off, maintain stable output signal; The moment of conducting after the first switching tube cut-off; or when having other surge impact in circuit; voltage peak absorbing circuit by the due to voltage spikes fast conducting of the current sample input of Switching Power Supply control chip to ground; realize the function of filtering due to voltage spikes; thus protect chip; prevent chip false triggering, improve stability, the reliability of circuit further.
Accompanying drawing explanation
Fig. 1 is the circuit theory diagrams of existing switching power circuit;
Fig. 2 is the schematic diagram of an embodiment of the voltage peak absorbing circuit that the utility model provides;
Fig. 3 is the circuit block diagram of the switching power circuit that the utility model provides;
Fig. 4 is the circuit theory diagrams of the first embodiment of the switching power circuit that the utility model provides;
Fig. 5 is the circuit theory diagrams of the second embodiment of the switching power circuit that the utility model provides.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, be clearly and completely described the technical scheme in the utility model embodiment, obviously, described embodiment is only the utility model part embodiment, instead of whole embodiments.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the utility model protection.
See Fig. 2, be the circuit theory diagrams of an embodiment of the voltage peak absorbing circuit that the utility model provides.
In the present embodiment, voltage peak absorbing circuit 201 includes spike test side a, earth terminal b, second switch pipe Q2, the first electric capacity C1 and the first resistance R1; Second switch pipe Q2 is NPN type triode, the control end of second switch pipe, first end and the second end, corresponding to the base stage of NPN type triode, collector electrode pole, emitter; The first end of second switch pipe Q2 connects described spike test side a, and the second end connects described earth terminal b; The first end of the first electric capacity C1 connects described spike test side a, and the second end connects the control end of described second switch pipe Q2; The first end of described first resistance R1 connects second end of described first electric capacity C1, and second end of described first resistance R1 connects described earth terminal b.
The course of work of voltage peak absorbing circuit 201 is such: when spike test side a detects due to voltage spikes, suddenly the pressure drop increased is added to the first electric capacity C1 two ends by the first resistance R1 by spike test side a and earth terminal b, because the first electric capacity C1 both end voltage can not be suddenlyd change, the electric current flowing through the first electric capacity C1 is i
c=Cdu
c/ dt, therefore, voltage upper punch on a of spike test side is faster, the electric current flowing through the first electric capacity C1 is larger, because the first electric capacity C1 connects with the first resistance R1, when electric current is enough large, voltage on first resistance R1 is higher than the conducting voltage of second switch pipe Q2, second switch pipe Q2 conducting, forms short circuit between spike test side a and earth terminal b, thus reaches the object due to voltage spikes on spike test side being conducting to ground.
The voltage peak absorbing circuit that the utility model provides, due to voltage spikes is obtained by spike test side, by electric capacity, fast-changing for magnitude of voltage signal is passed to switching tube, the conducting of control switch pipe, by the due to voltage spikes fast conducting on spike test side to ground, realize the function of filtering due to voltage spikes, effectively can avoid the problems such as electronic component damages, circuit working is abnormal.
See Fig. 3, it is the circuit block diagram of the switching power circuit that the utility model provides.
This switching power circuit comprises power input Vin, power output end Vout, transformer T1, the first switching tube Q1, Switching Power Supply control chip U1, sample circuit Rs and voltage peak absorbing circuit 201, described power input Vin is connected with the first end of the primary coil of described transformer T1, and described power output end Vout is connected with the secondary coil of described transformer T1;
Second end of the primary coil of described transformer T1 connects the first end of described first switching tube Q1, and second end of described first switching tube Q1 connects the first end of described sample circuit Rs, the second end ground connection of described sample circuit Rs;
Described Switching Power Supply control chip U1 comprises drive singal output GATE and current sample input CS; The first end of described sample circuit Rs connects described current sample input CS, and described drive singal output GATE connects the control end of described first switching tube Q1;
The spike test side a of described voltage peak absorbing circuit 201 connects described current sample input CS, the earth terminal b ground connection of described voltage peak absorbing circuit 201.
See Fig. 4, be the circuit theory diagrams of the first embodiment of the switching power circuit that the utility model provides.As shown in Figure 3, switching power circuit specifically comprises power input Vin, power output end Vout, transformer T1, the first switching tube Q1, Switching Power Supply control chip U1, sample circuit Rs and voltage peak absorbing circuit 201.
In the present embodiment, the first switching tube Q1 is N-type field effect transistor, the control end of the first switching tube, first end and the second end, corresponding to the grid of N-type field effect transistor, drain electrode, source electrode; The operation principle of Switching Power Supply control chip U1 is: Switching Power Supply control chip inside is provided with reference voltage, drive singal output GATE's is output-controlled in the voltage compare result of current sample input CS and Switching Power Supply control chip internal reference voltage, export square-wave signal, if current sample input CS voltage is more higher than internal reference voltage, then the duty ratio (ratio in the duration of positive pulse and pulse total cycle) of drive singal output GATE output signal is less, otherwise then larger; Sample circuit Rs is single resistor; The first end of described sample circuit Rs connects described current sample input, is specially: the first end of sample circuit Rs connects current sample input CS by the second resistance R2; Described drive singal output connects the control end of described first switching tube, is specially: drive singal output GATE connects the control end of described first switching tube Q1 by the 4th resistance R4.
When there is due to voltage spikes in the first end of sample circuit Rs; first end due to sample circuit Rs connects current sample input CS; the spike test side a of voltage peak absorbing circuit 201 also connects current sample end CS; therefore the pressure drop between spike test side a and earth terminal b can increase suddenly; now between spike test side a and earth terminal b short circuit by the voltage peak absorbing on current sample input to ground; realize the function of filtering spike; protect Switching Power Supply control chip, also prevent the false triggering of Switching Power Supply control chip.
If due to voltage spikes is due to the first switching tube Q1 conducting, transformer T1 parasitic capacitance discharge and occurring, then after due to voltage spikes, first switching tube Q1 conducting, the primary current of transformer T1 linearly increases, the voltage linear of the first end of sample circuit Rs increases, because the change in voltage of the first end of sample circuit Rs is slow, the electric current on the first electric capacity C1 is very little, and therefore second switch pipe Q2 cannot conducting; If due to voltage spikes occurs because circuit is subject to other inrush current shock, after due to voltage spikes, transformer T1 primary current keeps original steady-working state, and similarly, second switch pipe Q2 cannot conducting.Therefore, voltage peak absorbing circuit 201 can not affect the normal work of switching power circuit.
Referring to Fig. 5, is the circuit theory diagrams of the second embodiment of the switching power circuit that the utility model provides.
The switching power circuit that the present embodiment provides, compared with the first above-mentioned embodiment, its difference is that switching power circuit further comprises the 3rd resistance R3, and the first end of the 3rd resistance R3 connects current sample input CS, the second end ground connection.3rd resistance R3 is formed with the second resistance R2 and connects, dividing potential drop is carried out to sample circuit Rs, reduce the magnitude of voltage be connected on current sample input CS, compare the first embodiment, in the present embodiment, sample circuit Rs is when normally working, two ends can be born larger normal working voltage and can not continue to provide high voltage on the current sample pin of Switching Power Supply control chip, avoid damaging Switching Power Supply control chip U1.
It should be noted that, in the voltage peak absorbing circuit that above-described embodiment provides and switching power circuit, first switching tube Q1 is N-type field effect transistor, second switch pipe Q2 is NPN triode, be only a kind of execution mode wherein, in other embodiments, first switching tube Q1 can also replace with NPN type triode or other three ends control switch device or its and derive from device, second switch pipe Q2 also can replace with N-type field effect transistor or other three ends control switch device or its and derive from device, in different application scenarios, depending on the power consumption of side circuit, cost, driving power and require reasonable selection and setting with the drived control component parameter matching etc. of switching tube, select and the conventional design process that switching tube is prior art is set, do not repeat at this.In addition, in the switching power circuit that above-described embodiment provides, sample circuit Rs is single resistor, and in other embodiments, sample circuit Rs also can be the connection in series-parallel assembly of multiple resistor.
The switching power circuit that the utility model provides, obtains the magnitude of voltage on sample circuit first end by Switching Power Supply control chip, adjusts the time scale of the first switching tube conducting and cut-off, maintain stable output signal; The moment of conducting after the first switching tube cut-off; or when having other surge impact in circuit; voltage peak absorbing circuit by the due to voltage spikes fast conducting of the current sample input of Switching Power Supply control chip to ground; realize the function of filtering due to voltage spikes; thus protect chip; prevent chip false triggering, improve stability, the reliability of circuit further.
The above is the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvement and distortion, these improve and distortion is also considered as protection scope of the present invention.
Claims (8)
1. a voltage peak absorbing circuit, is characterized in that, comprises spike test side, earth terminal, second switch pipe, the first electric capacity and the first resistance;
The first end of described second switch pipe connects described spike test side, and the second end of described second switch pipe connects described earth terminal;
The first end of described first electric capacity connects described spike test side, and the second end of described first electric capacity connects the control end of described second switch pipe;
The first end of described first resistance connects the second end of described first electric capacity, and the second end of described first resistance connects described earth terminal.
2. voltage peak absorbing circuit as claimed in claim 1, it is characterized in that, described second switch pipe is NPN type triode, the base stage of described NPN type triode is the control end of described second switch pipe, the first end of the very described second switch pipe of current collection of described NPN type triode, the second end of the very described second switch pipe of transmitting of described NPN type triode.
3. a switching power circuit, is characterized in that, comprises power input, power output end, transformer, the first switching tube, Switching Power Supply control chip, sample circuit and voltage peak absorbing circuit as claimed in claim 1 or 2;
Described power input is connected with the first end of the primary coil of described transformer, and described power output end is connected with the secondary coil of described transformer;
Second end of the primary coil of described transformer connects the first end of described first switching tube, and the second end of described first switching tube connects the first end of described sample circuit, the second end ground connection of described sample circuit;
Described Switching Power Supply control chip comprises drive singal output and current sample input; The first end of described sample circuit connects described current sample input, and described drive singal output connects the control end of described first switching tube;
The spike test side of described voltage peak absorbing circuit connects described current sample input, the earth terminal ground connection of described voltage peak absorbing circuit.
4. switching power circuit as claimed in claim 3, it is characterized in that, described first switching tube is N-type field effect transistor, the grid of described N-type field effect transistor is the control end of described first switching tube, the drain electrode of described N-type field effect transistor is the first end of described first switching tube, and the source electrode of described N-type field effect transistor is the second end of described first switching tube.
5. switching power circuit as claimed in claim 3, it is characterized in that, described sample circuit is single independently resistor, or the connection in series-parallel assembly of multiple resistor.
6. the switching power circuit as described in any one of claim 3 to 5, is characterized in that, described switching power circuit also comprises the second resistance;
The first end of described sample circuit connects described current sample input, is specially: the first end of described sample circuit connects described current sample input by described second resistance.
7. the switching power circuit as described in any one of claim 3 to 5, is characterized in that, described switching power circuit also comprises the 3rd resistance, and the first end of described 3rd resistance connects described current sample input, the second end ground connection of described 3rd resistance.
8. the switching power circuit as described in any one of claim 3 to 5, is characterized in that, described switching power circuit also comprises the 4th resistance;
Described drive singal output connects the control end of described first switching tube, is specially: described drive singal output connects the control end of described first switching tube by described 4th resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520833537.6U CN205070778U (en) | 2015-10-23 | 2015-10-23 | Voltage peak absorption circuit and switching power supply circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520833537.6U CN205070778U (en) | 2015-10-23 | 2015-10-23 | Voltage peak absorption circuit and switching power supply circuit |
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| CN205070778U true CN205070778U (en) | 2016-03-02 |
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| CN201520833537.6U Active CN205070778U (en) | 2015-10-23 | 2015-10-23 | Voltage peak absorption circuit and switching power supply circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113162190A (en) * | 2021-05-10 | 2021-07-23 | 深圳市卓朗微电子有限公司 | Novel control circuit and method for lithium battery pack based on 0Z8952 chip |
| CN114679043A (en) * | 2022-05-26 | 2022-06-28 | 深圳市首航新能源股份有限公司 | Voltage spike suppression method, control unit and resonant converter |
-
2015
- 2015-10-23 CN CN201520833537.6U patent/CN205070778U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113162190A (en) * | 2021-05-10 | 2021-07-23 | 深圳市卓朗微电子有限公司 | Novel control circuit and method for lithium battery pack based on 0Z8952 chip |
| CN114679043A (en) * | 2022-05-26 | 2022-06-28 | 深圳市首航新能源股份有限公司 | Voltage spike suppression method, control unit and resonant converter |
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