CN202906437U - Input undervoltage protection circuit - Google Patents
Input undervoltage protection circuit Download PDFInfo
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- CN202906437U CN202906437U CN 201220493771 CN201220493771U CN202906437U CN 202906437 U CN202906437 U CN 202906437U CN 201220493771 CN201220493771 CN 201220493771 CN 201220493771 U CN201220493771 U CN 201220493771U CN 202906437 U CN202906437 U CN 202906437U
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- undervoltage protection
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Abstract
The utility model discloses an input undervoltage protection circuit. The input undervoltage protection circuit is characterized in that the input undervoltage protection circuit comprises an input voltage sampling circuit, a switch circuit, a hysteresis circuit, a remote control port, a power supply biasing circuit, and a controlled port, an input end of the input voltage sampling circuit is connected to voltage input, an output end of the sampling circuit is connected to a control input end of the switch circuit, a control output end of the switch circuit is connected to the input of the controlled port and an input end of the hysteresis circuit, an output end of the hysteresis circuit is connected to the remote control port and a dividing node of the input sampling circuit, the input of the power supply biasing circuit is connected to a working power supply, and the output of the biasing circuit is connected to a working voltage input end of the switch circuit. The undervoltage protection circuit of the utility model is applied to an AC-DC/DC-DC module power supply with a remote control function, especially a module power supply of high power density and a small size, and has the characteristics of small size and low cost.
Description
Technical field
The utility model relates to a kind of input undervoltage protection circuit, particularly a kind of input undervoltage protection circuit with distant control function.
Prior art
In present modular power source field, particularly small power module power source generally all requires to have simultaneously distant control function and under-voltage protection function.Above-mentioned distant control function is in order to make things convenient for application system equipment, uses small-signal that modular power source is carried out work and idle control claims distant control function.The functional pin that for this reason increases is called remote control pin (REM).
Above-mentioned under-voltage protection function is, modular power source is crossed low and power supply itself or supplying cell that cause damage in order to prevent at input voltage, controls power remove and designed protective circuit.
Realize circuit such as Fig. 1-1 of these two functions in using at present; Shown in Fig. 1-2, realize with independently distant control function circuit and under-voltage protecting circuit, such as Fig. 1-1 circuit, remote control circuit is to adopt the triode of input voltage sampling and two NPN to realize; Such as Fig. 1-2 circuit, under-voltage protecting circuit adopts discharge circuit to realize, the shortcoming of sort circuit implementation is that number of devices is many, and circuit is complicated, and cost is high.In the power supply of small size, high power density, be difficult to realize.
The utility model content
Order of the present utility model provides a kind of input undervoltage protection circuit, has simultaneously under-voltage protection and distant control function, and circuit is simple, volume is little, cost is low.
Purpose described in the utility model is achieved through the following technical solutions:
A kind of input undervoltage protection circuit, comprise input voltage sample circuit, switching circuit, hysteresis circuit, remote control control port, power supply biasing circuit, controlled terminal mouth, the input termination voltage input of input voltage sample circuit, the output of sample circuit is received the control input end of switching circuit; The control output end of switching circuit is connected to the input of controlled terminal mouth and the input of hysteresis circuit, the output of hysteresis circuit is connected on the dividing potential drop node in remote control port and the input sampling circuit, the input of power supply biasing circuit connects working power, and biasing circuit output connects the operating voltage input in the switching circuit.
Under-voltage protecting circuit described in the utility model; have under-voltage protection and distant control function; the implementation procedure of under-voltage protection function: when input voltage reaches undervoltage condition; through described input sampling circuit sampling input undervoltage signal; by described switching circuit; the level of controlled terminal mouth is dragged down, reach the purpose of under-voltage protection.
In order to prevent behind input undervoltage; power supply is put frequent switching on and shutting down at critical input voltage; at this moment described hysteresis circuit further drags down under-voltage incoming signal level, if power supply will recover normal operation, needing input voltage to exceed set hysteresis electrical voltage point than under-voltage protection point could realize.
The implementation procedure of function distant control function: when normal operation, unsettled or the high level state of remote control level, when the remote control low level pulse signal that is lower than 1.2V is added to the REM port, this low level signal drags down the output level of sample circuit, and switching circuit action drags down the controlled terminal level of power supply, reached the purpose of power cutoff, when the control level of remote control pin returns to 3.5V or when above, switch turn-offs, power up work.
Compared with prior art, the utility model is when satisfying same under-voltage protection, hysteresis recovery, remote control switch function, and the number of devices of built-up circuit is few, circuit is simple; Shared cloth board space is little; Circuit cost is low.
Description of drawings
Fig. 1-1 is the under-voltage protecting circuit schematic diagram of prior art;
Fig. 1-2 is the remote control circuit schematic diagram of prior art;
Fig. 2 is the circuit diagram of the utility model embodiment one;
Fig. 3 is the circuit diagram of the utility model embodiment two;
Fig. 4 is the circuit diagram of the utility model embodiment three.
Embodiment
The utility model is described in further detail below in conjunction with the drawings and specific embodiments.
Fig. 2 shows the under-voltage protecting circuit of the integrated distant control function of the utility model embodiment one, comprises the input voltage sample circuit, switching circuit, hysteresis circuit, remote control control port REM, power supply biasing circuit, controlled terminal mouth COM.
Above-mentioned input voltage sample circuit comprises: voltage stabilizing didoe Da, the first divider resistance Ra, the second divider resistance Rc, the 3rd divider resistance Re.Ra, Re, Rc connect successively; The negative electrode of described voltage stabilizing didoe is received the input Vin of power supply, and anode is received Ra one end of above-mentioned voltage stabilizing didoe series circuit; Remote control control port REM receives the series connection node place of Ra and Rc, the input of the series connection node access switching circuit of Rc and Re, the lower termination power public terminal GND of the 3rd divider resistance Re.
Said switching circuit comprises switching tube Qa and the switching tube Qb that two NPN triodes form, input signal connects the base stage of Qb, the collector electrode of Qb connects the base stage of Qa and the input of power supply biasing circuit, the emitter of Qb connects public terminal GND, the emitter of Qa connects the public terminal GND of power supply, and the collector electrode of Qa meets the controlled terminal mouth COM of power supply.
Above-mentioned remote control control port is on the series connection node that is connected between the first divider resistance Ra and the second divider resistance Rc, utilizes outside input signal realization to the control of switching circuit.
Above-mentioned hysteresis circuit comprises resistance R d and diode Dc, and the negative electrode of Dc connects the collector electrode of the output Qa of switching circuit, the end of the anode connecting resistance Rd of Dc, another termination remote control control port REM of resistance R d.
Above-mentioned power supply biasing circuit comprises resistance R b, the upper termination VCC power supply of Rb, and the lower collector electrode of switch Qb and the base stage of Qa of terminating to of Rb is for the collector electrode of Qb and the base stage of Qa provide bias current.
Above-mentioned controlled terminal mouth COM is connected to the collector electrode of Qa and the output of hysteresis circuit by the diode Db that plays buffer action.When normal operation, unsettled or the high level state of remote control level, when the remote control low level pulse signal that is lower than 1.2V is added on the REM port, this low level signal drags down the output level of sample circuit, and switching circuit action drags down the controlled terminal level of power supply, reached the purpose of power cutoff, when the control level of remote control pin returns to 3.5V or when above, switch turn-offs, power up work.
Fig. 3 is the second embodiment circuit diagram of the present utility model, different from embodiment one is the input voltage sample circuit, voltage stabilizing didoe Da and the first divider resistance Ra two ends parallel connection a capacitor C 1, the negative electrode of the termination Da of C1, another termination remote control control port.C1 mainly has been the effect that static absorbs, and prevents that static from entering from remote control pin, causes damage or trigger protection circuit operation to device.
Fig. 4 is the 3rd embodiment circuit diagram of the present utility model, and different from embodiment one is the input voltage sample circuit, connects a capacitor C 2 between remote control control port and the power supply common port.C2 mainly has been the effect that static absorbs, and prevents that static from entering from remote control pin, causes damage or trigger protection circuit operation to device.
Execution mode of the present utility model is not limited to this according to foregoing of the present utility model; utilize ordinary skill knowledge and the customary means of this area; do not breaking away under the above-mentioned basic fundamental thought of the utility model prerequisite; the implementation circuit can also be made modification, replacement or the change of other various ways in the utility model, all drops within the utility model rights protection scope.
Claims (9)
1. input undervoltage protection circuit, it is characterized in that comprising input voltage sample circuit, switching circuit, hysteresis circuit, remote control control port, power supply biasing circuit, controlled terminal mouth, the input termination voltage input of input voltage sample circuit, the output of sample circuit is received the control input end of switching circuit; The control output end of switching circuit is connected to the input of controlled terminal mouth and the input of hysteresis circuit, the output of hysteresis circuit is connected on the dividing potential drop node in remote control port and the input sampling circuit, the input of power supply biasing circuit connects working power, and biasing circuit output connects the operating voltage input in the switching circuit.
2. input undervoltage protection circuit according to claim 1, it is characterized in that: described input voltage sample circuit comprises, voltage stabilizing didoe, the first divider resistance, the second divider resistance, the 3rd divider resistance; The first divider resistance, the second divider resistance, the 3rd divider resistance are connected successively; The negative electrode of described voltage stabilizing didoe is received the input of power supply, and the anode of described voltage stabilizing didoe is received an end of the first divider resistance, a termination power common port of the 3rd divider resistance.
3. input undervoltage protection circuit according to claim 1; it is characterized in that: described switching circuit comprises two NPN the first triodes and the second triode; input signal connects the base stage of the second triode; the collector electrode of the second triode connects the base stage of the first triode and the input of power supply biasing circuit; the emitter of the second triode connects common port; the emitter of the first triode connects the common port of power supply, and the collector electrode of the second triode connects the controlled terminal of power supply.
4. input undervoltage protection circuit according to claim 2 is characterized in that: the link of inputting remote signal between described the first divider resistance and the second divider resistance as the connection outside.
5. input undervoltage protection circuit according to claim 1; it is characterized in that: described hysteresis circuit comprises the first resistance and the first diode; the negative electrode of the first diode connects the output of switching circuit; the anode of the first diode connects an end of the first resistance, another termination remote control control port REM of the first resistance.
6. input undervoltage protection circuit according to claim 1, it is characterized in that: described power supply biasing circuit comprises the second resistance, a termination operating voltage power supply of the second resistance, the operating voltage input of another termination switching circuit of the second resistance.
7. input undervoltage protection circuit according to claim 1, it is characterized in that: described controlled terminal mouth is connected to the output of hysteresis circuit by isolating diode.
8. input undervoltage protection circuit according to claim 2, it is characterized in that: also comprise the first electric capacity, an end of the first electric capacity connects the negative electrode of described voltage stabilizing didoe, and the other end of the first electric capacity connects the remote control control port.
9. the input undervoltage protection circuit claimed in claim 2 that follows up is characterized in that: also comprise the second electric capacity, an end of the second electric capacity connects remote control control port, another termination power common port of the second electric capacity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220493771 CN202906437U (en) | 2012-09-25 | 2012-09-25 | Input undervoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220493771 CN202906437U (en) | 2012-09-25 | 2012-09-25 | Input undervoltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202906437U true CN202906437U (en) | 2013-04-24 |
Family
ID=48127062
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220493771 Expired - Fee Related CN202906437U (en) | 2012-09-25 | 2012-09-25 | Input undervoltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202906437U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103986320A (en) * | 2014-05-26 | 2014-08-13 | 广州金升阳科技有限公司 | Switch power source remote control 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 |
| CN109546847A (en) * | 2019-01-16 | 2019-03-29 | 合肥惠科金扬科技有限公司 | Synchronization breaking circuit, driving circuit and the synchronous cut-off method of Switching Power Supply |
| CN110071478A (en) * | 2019-04-08 | 2019-07-30 | 南京巨鲨显示科技有限公司 | A kind of display system under-voltage protecting circuit |
-
2012
- 2012-09-25 CN CN 201220493771 patent/CN202906437U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103986320A (en) * | 2014-05-26 | 2014-08-13 | 广州金升阳科技有限公司 | Switch power source remote control 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 |
| CN109546847A (en) * | 2019-01-16 | 2019-03-29 | 合肥惠科金扬科技有限公司 | Synchronization breaking circuit, driving circuit and the synchronous cut-off method of Switching Power Supply |
| CN110071478A (en) * | 2019-04-08 | 2019-07-30 | 南京巨鲨显示科技有限公司 | A kind of display system under-voltage protecting circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20130424 Termination date: 20160925 |
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| CF01 | Termination of patent right due to non-payment of annual fee |