CN202737446U - Over-voltage protection circuit of switching power supply - Google Patents
Over-voltage protection circuit of switching power supply Download PDFInfo
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- CN202737446U CN202737446U CN201220413094.1U CN201220413094U CN202737446U CN 202737446 U CN202737446 U CN 202737446U CN 201220413094 U CN201220413094 U CN 201220413094U CN 202737446 U CN202737446 U CN 202737446U
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- nand gate
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- switching power
- comparator
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- 230000004224 protection Effects 0.000 title claims abstract description 22
- 230000001681 protective effect Effects 0.000 claims description 39
- 238000012360 testing method Methods 0.000 abstract description 4
- 238000005070 sampling Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 2
- 208000031361 Hiccup Diseases 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
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Abstract
本实用新型为开关电源的过压保护电路，开关电源输出电压采样值接入比较器正相输入端，保护电压设定值接入比较器反相输入端，比较器输出端与反相器输入端连接，反相器输出端接入第一与非门一号输入端，第一与非门二号输入端与第二与非门输出端连接，第一与非门输出端和第二与非门一号输入端共同为本电路输出端、接PWM控制器使能端，第二与非门二号输入端经复位按键开关接地，PWM控制器控制开关电源输出端的通断。正常时本电路不工作，输出低电平；过压时本电路输出高电平，PWM控制器关断开关电源输出并锁定，复位按键接通才恢复正常；本电路锁定保护状态手动恢复便于测试和判定故障；模拟与数字器件相结合，控制电平稳定，过压保护可靠。
The utility model is an overvoltage protection circuit for a switching power supply. The sampling value of the output voltage of the switching power supply is connected to the normal phase input terminal of the comparator, the set value of the protection voltage is connected to the negative phase input terminal of the comparator, and the output terminal of the comparator is connected to the input terminal of the inverter. The output terminal of the inverter is connected to the No. 1 input terminal of the first NAND gate, the No. 2 input terminal of the first NAND gate is connected to the output terminal of the second NAND gate, and the output terminal of the first NAND gate is connected to the No. 2 NAND gate output terminal. The first input terminal of the NOT gate is the output terminal of the circuit, which is connected to the enable terminal of the PWM controller, the second input terminal of the second NAND gate is grounded through the reset button switch, and the PWM controller controls the on-off of the output terminal of the switching power supply. The circuit does not work normally and outputs low level; when overvoltage, the circuit outputs high level, the PWM controller turns off the output of the switching power supply and locks it, and the reset button is turned on to return to normal; the circuit locks the protection state and restores it manually for easy testing and determine faults; the combination of analog and digital devices, the control level is stable, and the overvoltage protection is reliable.
Description
Technical field
The utility model relates to the protective circuit of Switching Power Supply, is specially a kind of overvoltage crowbar of Switching Power Supply.
Background technology
Switching Power Supply now is widely used, in order to protect power consumption equipment and the Switching Power Supply that connects, and existing multiple overvoltage, the protective circuit such as under-voltage and overheated.The overvoltage crowbar of most Switching Power Supplies adopts the analog circuit combination of devices such as triode, resistance, electric capacity, voltage-stabiliser tube to form, and can not accurately judge for the magnitude of voltage of logic level locking and logic level.
For improving the reliability of protective circuit, the protective circuit of switch power source that analog circuit combines with digital circuit has now appearred.It is 200620000754 Chinese utility model patent " Switching Power Supply hiccup protections circuit " such as the patent No.; utilize comparator monitoring output voltage, output overcurrent; the output signal of comparator is turn-offed pwm circuit when overvoltage or overcurrent, realizes the protection to Switching Power Supply.This protective circuit adopts the form of discrete circuit, and manufacturing cost is higher, and can repeatedly connect cut-off protection circuit in high frequency ground, causes the components and parts life-span of protective circuit not long.Application number is 201010619979 Chinese invention patent application " protective circuit of Switching Power Supply " for another example; the ambient temperature of testing circuit sense switch power supply and export whether overvoltage, under-voltage, guard signal are sent to the output that NAND gate, control rest-set flip-flop are cut off Switching Power Supply.In case enter just locking of guard mode, only have this protective circuit to restart, could remove the guard mode that Switching Power Supply is judged.Although the Reliability Enhancement of this protective circuit, the locking of de-preservation state needs restarting of whole protective circuit, uses not very convenient.The release of guard mode mostly is automatic unlocking in other the scheme, and inconvenient operating personnel are to judgement and the test of malfunction.
The utility model content
The purpose of this utility model is to design a kind of overvoltage crowbar of Switching Power Supply; comprise comparator and NAND gate; when overvoltage appears in the output of Switching Power Supply; comparator is measured immediately; when NAND gate was output as high level, its pulse width modulation that connects (PWM Pulse Width Modulation) controller cut off Switching Power Supply.NAND gate keeps high level, and the locking guard mode discharges high level after manually pressing reset key, unlocks.
The overvoltage crowbar of the Switching Power Supply of the utility model design comprises comparator; NAND gate; the Switching Power Supply output is electrically connected with the normal phase input end of comparator through sample circuit; the inverting input of protection voltage setting value access comparator; this overvoltage crowbar also has 1 inverter and 2 NAND gate; the output of comparator is electrically connected with the input of inverter; the output of inverter accesses an input of the first NAND gate; No. two inputs of the first NAND gate are electrically connected with the output of the second NAND gate; an input of the output of the first NAND gate and the second NAND gate is connected to the Enable Pin of pulse width modulation (PWM) controller jointly as the output of this protective circuit; No. two inputs of the second NAND gate are through reset button switch ground connection, and this reset button switch normal condition is normally open.The output of the Switching Power Supply that this protective circuit of control end connection control of described Pwm controller is protected.Be specially: the control end of described Pwm controller connects the switching tube driver element of control switch power supply, the break-make of control switch pipe, thereby the break-make of the output of control switch power supply.
This protective circuit power supply is electrically connected to the power input of comparator, inverter, the first NAND gate and the second NAND gate.
The power input of comparator is electrically connected to the output of comparator through the first resistance.
This protective circuit power supply is electrically connected to No. two inputs of the second NAND gate through the second resistance.
Less than the protection voltage setting value, this protective circuit was not worked when the sampled value of Switching Power Supply output end voltage was normal, the output of the first NAND gate, or the output of saying this protective circuit is low level.Switching Power Supply output end voltage generation overvoltage, output voltage sampled value are greater than the protection voltage setting value; the normal phase input end voltage of comparator is higher than the anti-phase input terminal voltage; the output of comparator is after the first resistance, inverter and first, second NAND gate; the output of this protective circuit is high level; high level signal is sent into the Enable Pin of Pwm controller; turn-off the pwm signal output of Pwm controller; the switching tube driver element of stopcock power supply, thereby the output of stopcock power supply.Even this moment, the Switching Power Supply output end voltage recovered normal range (NR), the output of this protective circuit still is high level, and Pwm controller keeps the output of stopcock power supply.Make it to connect when manually pressing reset key; the reset key ground connection of the high level of this protective circuit output by connecting, revert to low level; the Pwm controller protection is closed; PWM is normally output again; the output of Switching Power Supply recloses; hand one is decontroled reset key and is recovered normally open, and this protective circuit enters again idle normal condition.
Compared with prior art, the advantage of the overvoltage crowbar of the utility model Switching Power Supply is: 1, being combined with digital device by analogue device consists of, the control signal level equalization, and the overvoltage protection of Switching Power Supply is reliable; 2, enter immediately locking after the guard mode, nobody unlocks, can not change the guard mode of Switching Power Supply, and convenient operation personnel test switch power supply system, and judge guilty culprit; 3, unlock and only need to manually click reset key, simple to operation; 4, this protective circuit is output as logic level signal (only having high level and low level), is easier to and the equipment seamless links such as computer, PLC, single-chip microcomputer.
Description of drawings
Fig. 1 is the overvoltage crowbar embodiment schematic diagram of this Switching Power Supply.
The figure internal label is:
U1: comparator, U2: inverter, U3: the first NAND gate; U4: the second NAND gate; R1: the first resistance, R2: the second resistance, S1: reset button switch; VCC: this protective circuit power supply anode; REF: protection voltage setting value, VFB: Switching Power Supply output end voltage sampled value, VCTR: protection control level; GND: this protective circuit power supply negative terminal, i.e. ground connection.
Embodiment
Describe the overvoltage crowbar embodiment of this Switching Power Supply in detail below in conjunction with accompanying drawing.
Figure 1 shows that this routine circuit diagram.
The overvoltage crowbar embodiment of this Switching Power Supply comprises comparator; 2 resistance; 1 inverter; with 2 NAND gate; the normal phase input end of the sampled value VFB access comparator U1 of the voltage of Switching Power Supply output after sample circuit; the inverting input of protection voltage setting value REF access comparator U1; the output of comparator U1 is electrically connected with the input of inverter U2; the output of inverter U2 accesses the input of the first NAND gate U3; No. two inputs of the first NAND gate U3 are electrically connected with the output of the second NAND gate U4; the input of the output of the first NAND gate U3 and the second NAND gate U4 is jointly as the output of this protective circuit; be connected to the Enable Pin of Pwm controller; output protection control level VCTR; No. two inputs of the second NAND gate U4 are through reset button switch S1 ground connection, and this reset button switch S1 normal condition is normally open.The control end of described Pwm controller connects the Switching Power Supply output that this protective circuit of control is protected.
This protective circuit power supply VCC is electrically connected to the power input of comparator U1, inverter U2, the first NAND gate U3 and the second NAND gate U4.
This protective circuit power supply VCC is electrically connected to the output of comparator U1 through the first resistance R 1.
This protective circuit power supply VCC is electrically connected to No. two inputs of the second NAND gate U4 through the second resistance R 2.
This routine protective circuit power supply VCC is 15 volts, the also power supply of available 5～30 volts of fixed voltages, and the operating voltage range of comparator U1, inverter U2, the first NAND gate U3 and the second NAND gate U4 is depended in the selection of magnitude of voltage.
This protective circuit supply voltage value VCC is the high value of the protection control of this protective circuit output output, the i.e. high value of this protective circuit logic output level.
This example is used for the protection of the Switching Power Supply of 60KV/70mA at present, and is respond well.
Above-described embodiment only is the specific case that the purpose of this utility model, technical scheme and beneficial effect are further described, and the utility model is not to be defined in this.All any modifications of within scope of disclosure of the present utility model, making, be equal to replacement, improvement etc., all be included within the protection range of the present utility model.
Claims (5)
1. the overvoltage crowbar of Switching Power Supply comprises comparator, NAND gate, and the Switching Power Supply output is electrically connected with the normal phase input end of comparator through sample circuit, and the inverting input of protection voltage setting value access comparator is characterized in that:
Also have 1 inverter and 2 NAND gate, the output of comparator is electrically connected with the input of inverter, the output of inverter accesses an input of the first NAND gate, No. two inputs of the first NAND gate are electrically connected with the output of the second NAND gate, an input of the second NAND gate of the output of the first NAND gate jointly as the output of this protective circuit, be connected to the Enable Pin of Pwm controller, No. two inputs of the second NAND gate are through reset button switch ground connection, and this reset button switch normal condition is normally open; The control end of described Pwm controller connects the Switching Power Supply output that this protective circuit of control is protected;
This protective circuit power supply is electrically connected to the power input of comparator, inverter, the first NAND gate and the second NAND gate.
2. the overvoltage crowbar of Switching Power Supply according to claim 1 is characterized in that:
The power input of described comparator is electrically connected to the output of comparator through the first resistance.
3. the overvoltage crowbar of Switching Power Supply according to claim 2 is characterized in that:
Described protective circuit power supply is electrically connected to No. two inputs of the second NAND gate through the second resistance.
4. the overvoltage crowbar of Switching Power Supply according to claim 3 is characterized in that:
Described protective circuit power supply is the power supply of 5～30 volts of fixed voltages.
5. the overvoltage crowbar of Switching Power Supply according to claim 3 is characterized in that:
Described protective circuit supply voltage value is the high value of the protection control of this protective circuit output output.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220413094.1U CN202737446U (en) | 2012-08-20 | 2012-08-20 | Over-voltage protection circuit of switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220413094.1U CN202737446U (en) | 2012-08-20 | 2012-08-20 | Over-voltage protection circuit of switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202737446U true CN202737446U (en) | 2013-02-13 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201220413094.1U Expired - Lifetime CN202737446U (en) | 2012-08-20 | 2012-08-20 | Over-voltage protection circuit of switching power supply |
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| Country | Link |
|---|---|
| CN (1) | CN202737446U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103326713A (en) * | 2013-05-23 | 2013-09-25 | 苏州芯动科技有限公司 | Method and circuit for protecting multi-voltage-domain power adjustable voltage-controlled oscillator |
| CN105375442A (en) * | 2015-11-24 | 2016-03-02 | 上海空间电源研究所 | Weinberg circuit topology-based independent output overvoltage protection locking and unlocking system and method |
| CN106786394A (en) * | 2016-11-28 | 2017-05-31 | 珠海恒途电子有限公司 | Interlock protection circuit |
-
2012
- 2012-08-20 CN CN201220413094.1U patent/CN202737446U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103326713A (en) * | 2013-05-23 | 2013-09-25 | 苏州芯动科技有限公司 | Method and circuit for protecting multi-voltage-domain power adjustable voltage-controlled oscillator |
| CN103326713B (en) * | 2013-05-23 | 2016-03-30 | 苏州芯动科技有限公司 | The guard method of multiple voltage domain power supply adjusting type voltage controlled oscillator and circuit |
| CN105375442A (en) * | 2015-11-24 | 2016-03-02 | 上海空间电源研究所 | Weinberg circuit topology-based independent output overvoltage protection locking and unlocking system and method |
| CN106786394A (en) * | 2016-11-28 | 2017-05-31 | 珠海恒途电子有限公司 | Interlock protection circuit |
| CN106786394B (en) * | 2016-11-28 | 2019-05-10 | 珠海恒途电子有限公司 | Interlock protection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: GUILIN ELECTRICAL EQUIPMENT SCIENTIFIC RESEARCH IN Free format text: FORMER NAME: GUILIN ELECTRICAL EQUIPMENT SCIENTIFIC RESEARCH INSTITUTE |
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| CP01 | Change in the name or title of a patent holder |
Address after: 541004 the Guangxi Zhuang Autonomous Region Guilin Qixing Road, No. 1 Patentee after: GUILIN ELECTRICAL EQUIPMENT SCIENTIFIC RESEARCH INSTITUTE Co.,Ltd. Address before: 541004 the Guangxi Zhuang Autonomous Region Guilin Qixing Road, No. 1 Patentee before: Guilin Electrical Equipment Scientific Research Institute |
|
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20200422 Address after: 541004 industry test building, No.8, Dongcheng Road, Qixing District, Guilin City, Guangxi Zhuang Autonomous Region Patentee after: Guilin SAIMENG Testing Technology Co.,Ltd. Address before: 541004 No. 1, Chen Shan Road, Qixing District, Guilin, the Guangxi Zhuang Autonomous Region Patentee before: GUILIN ELECTRICAL EQUIPMENT SCIENTIFIC RESEARCH INSTITUTE Co.,Ltd. |
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| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130213 |