CN102064532B - Overvoltage protection circuit of input follower type - Google Patents
Overvoltage protection circuit of input follower type Download PDFInfo
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- CN102064532B CN102064532B CN 201110005601 CN201110005601A CN102064532B CN 102064532 B CN102064532 B CN 102064532B CN 201110005601 CN201110005601 CN 201110005601 CN 201110005601 A CN201110005601 A CN 201110005601A CN 102064532 B CN102064532 B CN 102064532B
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Abstract
The invention provides an overvoltage protection circuit of an input follower type, comprising an AC (Alternating Current) input end, a rectifier filter, a start circuit module, a VCC (Virtual Channel Connection) power supply circuit module and a PWM (Pulse Width Modulation) output circuit U2. The rectifier filter and the start circuit module are connected. The overvoltage protection circuit of the input follower type is characterized by also comprising an overvoltage protection circuit module with a stabilized voltage, one end of the overvoltage protection circuit module is directly connected with the AC input end, the other end of the overvoltage protection circuit module is respectively connected with the start circuit module and the VCC power supply circuit module, and the currents of the start circuit module and the VCC power supply circuit module are output to the PWM output circuit U2. The circuit provided by the invention has a simple structure, less elements, stability and reliability, solves the protection of a switching power supply with a wide input range, the voltage of a sampling point in front of a rectifier bridge is monitored in real time to vary with the AC input voltage, and the sampling voltage can avoid influencing voltage fluctuation because of the dynamic variance of an output load so as to improve the accuracy of overvoltage protection.
Description
[technical field]
The present invention relates to electronic circuit, particularly a kind of trailing type overvoltage crowbar.
[background technology]
The PWM drive IC of at present a lot of Switching Power Supplies does not possess overvoltage and under-voltage protection, when wide voltage is imported, tends to cause input voltage too high because of the fluctuation of electrical network, burns power supply or end product.Therefore when having the overvoltage protection requirement, Switching Power Supply can increase overvoltage crowbar; and traditional overvoltage crowbar voltage sampling point is generally all behind rectifier; its sampling voltage can not be followed input voltage accurately, can cause the protection voltage power supply unstable and not accurate enough.
[summary of the invention]
Purpose of the present invention is exactly for a kind of trailing type overvoltage crowbar of the Switching Power Supply protection for wide region input is provided.
Another object of the present invention is that the voltage of sampling point is before rectifier bridge, real-time monitoring and follow the variation of ac input voltage, and sampling voltage can not be subjected to the dynamic change of output loading to cause the influence of voltage fluctuation, improved the accuracy of overvoltage protection.
Concrete technical scheme of the present invention is as follows; a kind of input trailing type overvoltage crowbar is provided; comprise the AC input; rectifier filter; the start-up circuit module; VCC power supply circuits module; PWM output circuit U2; described rectifier filter links to each other with described start-up circuit module; it is characterized in that: comprise that also one has the overvoltage crowbar module of burning voltage; one end of described overvoltage crowbar module directly links to each other with the AC input; the other end respectively with the start-up circuit module; VCC power supply circuits module links to each other, described start-up circuit module; VCC power supply circuits blocks current outputs to PWM output circuit U2.
Described overvoltage crowbar module comprises TL431 integrated circuit U1, diode D1, filter capacitor C3, divider resistance R6, R7, R9, current-limiting resistance R8, in parallel with described filter capacitor C3 after described divider resistance R6, R7, the R9 series connection, described filter capacitor C3 links to each other other end ground connection via diode D1 with described AC input; Described current-limiting resistance R8 one end is connected between divider resistance R9, the R7, the other end links to each other with described TL431 integrated circuit U1 input, and the output of described TL431 integrated circuit U1 links to each other with described start-up circuit module, VCC power supply circuits module respectively.
Described overvoltage crowbar module also comprises filter capacitor C4, diode D2, diode D3, and described filter capacitor C4 one end links to each other with the earth terminal of TL431 integrated circuit U1, and the other end is connected between current-limiting resistance R8, the TL431 integrated circuit U1; Described diode D2, diode D3 are connected on respectively between the output of described TL431 integrated circuit U1 and start-up circuit module, the VCC power supply circuits module.
Described start-up circuit module comprises transformer T1, metal-oxide-semiconductor Q1, divider resistance R2, R3, diode D5, filter capacitor C5, described transformer T1 comprises elementary winding, secondary winding and auxiliary winding, described elementary winding comprises a end and b end, described b end is via drain electrode, the source ground of described metal-oxide-semiconductor Q1, and the grid of described metal-oxide-semiconductor Q1 is connected on the described PWM output circuit U2; Described filter capacitor C5, diode D5 series connection back is in parallel with described elementary winding; The diode D2 of described overvoltage crowbar module is connected to a end via divider resistance R2, R3, and the anode of described diode D2 is via capacitor C 7 ground connection, and the other end of described PWM output circuit U2 is received the anode of described diode D2.
Described start-up circuit module also comprises current-limiting resistance R11 and divider resistance R12, and described current-limiting resistance R11 is in parallel with described filter capacitor C5; Described divider resistance R12 is connected on the source electrode of metal-oxide-semiconductor Q1.
Described VCC power supply circuits module comprises diode D4, divider resistance R10, VCC end, the anode of described diode D4 links to each other with auxiliary winding via described divider resistance R10, and the anode of the diode D3 of described overvoltage crowbar module links to each other with the negative electrode of described diode D4 through described VCC end; Described VCC end links to each other with the 3rd end of described PWM output circuit U2.
Described VCC power supply circuits module also comprises capacitor C 5, and the negative electrode of described diode D4 is via described capacitor C 5 ground connection.
Compared to prior art, main beneficial effect of the present invention is: circuit structure of the present invention is simple, element is few, reliable and stable; Solved the protection of the Switching Power Supply of wide region input; The voltage of sampling point is before rectifier bridge, monitors and follow the variation of ac input voltage in real time, and sampling voltage can not be subjected to the dynamic change of output loading to cause the influence of voltage fluctuation, has improved the accuracy of overvoltage protection.
[description of drawings]
Fig. 1 is schematic diagram of the present invention;
Fig. 2 is overvoltage crowbar modular circuit schematic diagram of the present invention;
Fig. 3 is circuit block diagram of the present invention.
[embodiment]
The present invention relates to a kind of input trailing type overvoltage crowbar, describe technical scheme of the present invention in detail below in conjunction with accompanying drawing:
As shown in Figure 1; a kind of input trailing type overvoltage crowbar; comprise the AC input; rectifier filter; the start-up circuit module; VCC power supply circuits module; PWM output circuit U2; overvoltage crowbar module with burning voltage; described rectifier filter links to each other with described start-up circuit module; one end of described overvoltage crowbar module directly links to each other with the AC input; the voltage of sampling point is before rectifier bridge; the drift that can avoid so can not being subjected to the weight of load and influence sampling voltage; the other end respectively with the start-up circuit module; VCC power supply circuits module links to each other, described start-up circuit module; VCC power supply circuits blocks current outputs to PWM output circuit U2.
As shown in Figure 2, described overvoltage crowbar module comprises TL431 integrated circuit U1, diode D1, filter capacitor C3, divider resistance R6, R7, R9, current-limiting resistance R8, in parallel with described filter capacitor C3 after described divider resistance R6, R7, the R9 series connection, described filter capacitor C3 links to each other other end ground connection via diode D1 with described AC input; Described current-limiting resistance R8 one end is connected between divider resistance R9, the R7, the other end links to each other with described TL431 integrated circuit U1 input, and the output of described TL431 integrated circuit U1 links to each other with described start-up circuit module, VCC power supply circuits module respectively; And resistance R 1 one ends are connected the output of TL431 integrated circuit U1, and the other end is connected between current-limiting resistance R8, the TL431 integrated circuit U1; Described overvoltage crowbar module also comprises filter capacitor C4, diode D2, diode D3, and described filter capacitor C4 one end links to each other with the earth terminal of TL431 integrated circuit U1, and the other end is connected between current-limiting resistance R8, the TL431 integrated circuit U1; Described diode D2, diode D3 are connected on respectively between the output of described TL431 integrated circuit U1 and start-up circuit module, the VCC power supply circuits module.The voltage of sampling point is before rectifier bridge, monitors and follow the variation of ac input voltage in real time, and sampling voltage can not be subjected to the dynamic change of output loading to cause the influence of voltage fluctuation, has improved the accuracy of overvoltage protection.
As shown in Figure 1, described start-up circuit module comprises transformer T1, metal-oxide-semiconductor Q1, divider resistance R2, R3, diode D5, filter capacitor C5, described transformer T1 comprises elementary winding, secondary winding and auxiliary winding, described elementary winding comprises a end and b end, described b end is via drain electrode, the source ground of described metal-oxide-semiconductor Q1, and the grid of described metal-oxide-semiconductor Q1 is connected on the described PWM output circuit U2; Described filter capacitor C5, diode D5 series connection back is in parallel with described elementary winding; The diode D2 of described overvoltage crowbar module is connected to a end via divider resistance R2, R3, and the anode of described diode D2 is via capacitor C 7 ground connection, and the other end of described PWM output circuit U2 is received the anode of described diode D2; Described start-up circuit module also comprises current-limiting resistance R11 and divider resistance R12, and described current-limiting resistance R11 is in parallel with described filter capacitor C5; Described divider resistance R12 is connected on the source electrode of metal-oxide-semiconductor Q1.
As shown in Figure 1, described VCC power supply circuits module comprises diode D4, divider resistance R10, VCC end, and the anode of described diode D4 links to each other with auxiliary winding via described divider resistance R10, the other end ground connection of auxiliary winding; The anode of the diode D3 of described overvoltage crowbar module links to each other with the negative electrode of described diode D4 through described VCC end; Described VCC end links to each other with the 3rd end of described PWM output circuit U2; Described VCC power supply circuits module also comprises capacitor C 5, and the negative electrode of described diode D4 is via described capacitor C 5 ground connection.
As shown in Figure 3, utilize the TL431 integrated circuit to finish benchmark voltage, whether the comparison input voltage has the scope that exceeds setting, through power supply and the starting resistor of the PWM output circuit of controlling power supply more afterwards.Whether determine the work of PWM integrated circuit.When the input voltage overvoltage, the PWM output circuit stops output, when the benchmark that calculates relatively with: Ivo=[(1+R6+R7)/R9] the .VREF formula calculates.Ivo: input voltage over-voltage protection point; The datum mark voltage of VREF:TL431.Circuit structure is simple, element is few, reliable and stable; Solved the protection of the Switching Power Supply of wide region input.
Operation principle: just sampling behind the ac input voltage process EMI, through the D1 rectification, C3 filtering, R6, R7, R9 dividing potential drop, C4 considers ripple again, and U1 compares, and D2, D3 or a door electricity are controlled VCC voltage and start-up circuit simultaneously.When voltage exceeded the protection point of setting, the TL431 output low level dragged down VCC voltage and starting resistor by D2, D3, and the PWM output circuit does not end because there being operating voltage, thereby realized the overvoltage protection to power supply.
Though preferred embodiment of the present invention is disclosed with the purpose as illustration, it will be appreciated by those skilled in the art that various modifications, interpolation and replacement are possible, as long as it does not break away from the spirit and scope of the present invention that describe in detail in the claims.
Claims (6)
1. import the trailing type overvoltage crowbar for one kind, comprise the AC input, rectifier filter, the start-up circuit module, VCC power supply circuits module, PWM output circuit U2, described rectifier filter links to each other with described start-up circuit module, it is characterized in that: comprise that also one has the overvoltage crowbar module of burning voltage, one end of described overvoltage crowbar module directly links to each other with the AC input, the other end respectively with the start-up circuit module, VCC power supply circuits module links to each other, described start-up circuit module, VCC power supply circuits blocks current outputs to PWM output circuit U2; Described overvoltage crowbar module comprises TL431 integrated circuit U1, diode D1, filter capacitor C3, divider resistance R6, R7, R9, current-limiting resistance R8, in parallel with described filter capacitor C3 after described divider resistance R6, R7, the R9 series connection, described filter capacitor C3 links to each other other end ground connection via diode D1 with described AC input; Described current-limiting resistance R8 one end is connected between divider resistance R9, the R7, the other end links to each other with described TL431 integrated circuit U1 input, and the output of described TL431 integrated circuit U1 links to each other with described start-up circuit module, VCC power supply circuits module respectively.
2. input trailing type overvoltage crowbar according to claim 1, it is characterized in that: described overvoltage crowbar module also comprises filter capacitor C4, diode D2, diode D3, described filter capacitor C4 one end links to each other with the earth terminal of TL431 integrated circuit U1, and the other end is connected between current-limiting resistance R8, the TL431 integrated circuit U1; Described diode D2, diode D3 are connected on respectively between the output of described TL431 integrated circuit U1 and start-up circuit module, the VCC power supply circuits module.
3. input trailing type overvoltage crowbar according to claim 1 and 2, it is characterized in that: described start-up circuit module comprises transformer T1, metal-oxide-semiconductor Q1, divider resistance R2, R3, diode D5, filter capacitor C5, described transformer T1 comprises elementary winding, secondary winding and auxiliary winding, described elementary winding comprises a end and b end, described b end is via drain electrode, the source ground of described metal-oxide-semiconductor Q1, and the grid of described metal-oxide-semiconductor Q1 is connected on the described PWM output circuit U2; Described filter capacitor C5, diode D5 series connection back is in parallel with described elementary winding; The diode D2 of described overvoltage crowbar module is connected to a end via divider resistance R2, R3, and the anode of described diode D2 is via capacitor C 7 ground connection, and the other end of described PWM output circuit U2 is received the anode of described diode D2.
4. input trailing type overvoltage crowbar according to claim 3, it is characterized in that: described start-up circuit module also comprises current-limiting resistance R11 and divider resistance R12, described current-limiting resistance R11 is in parallel with described filter capacitor C5; Described divider resistance R12 is connected on the source electrode of metal-oxide-semiconductor Q1.
5. input trailing type overvoltage crowbar according to claim 1, it is characterized in that: described VCC power supply circuits module comprises diode D4, divider resistance R10, VCC end, the anode of described diode D4 links to each other with auxiliary winding via described divider resistance R10, and the anode of the diode D3 of described overvoltage crowbar module links to each other with the negative electrode of described diode D4 through described VCC end; Described VCC end links to each other with the 3rd end of described PWM output circuit U2.
6. input trailing type overvoltage crowbar according to claim 5, it is characterized in that: described VCC power supply circuits module also comprises capacitor C 5, the negative electrode of described diode D4 is via described capacitor C 5 ground connection.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110005601 CN102064532B (en) | 2011-01-12 | 2011-01-12 | Overvoltage protection circuit of input follower type |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201110005601 CN102064532B (en) | 2011-01-12 | 2011-01-12 | Overvoltage protection circuit of input follower type |
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| CN102064532A CN102064532A (en) | 2011-05-18 |
| CN102064532B true CN102064532B (en) | 2013-07-03 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110971111A (en) * | 2019-11-14 | 2020-04-07 | 中电科仪器仪表(安徽)有限公司 | Pulse width modulator auxiliary power supply circuit |
| CN112615425B (en) * | 2020-12-31 | 2023-09-08 | 广州金升阳科技有限公司 | Detection control circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5917716A (en) * | 1997-02-21 | 1999-06-29 | Samsung Electronics Co., Ltd. | Switching mode power supplier having function of protecting circuit from abnormal voltage |
| US6229681B1 (en) * | 1998-03-07 | 2001-05-08 | Samsung Electronics Co., Ltd. | Switching mode power supply apparatus having a low voltage protection circuit |
| CN2552047Y (en) * | 2002-06-19 | 2003-05-21 | 深圳市跨宏实业有限公司 | Switch power with wide input voltage range |
| CN101083433A (en) * | 2006-06-01 | 2007-12-05 | 株式会社理光 | Switch electric source device |
| CN201307764Y (en) * | 2008-11-26 | 2009-09-09 | 深圳桑达国际电子器件有限公司 | Power supply circuit with overvoltage protection function |
-
2011
- 2011-01-12 CN CN 201110005601 patent/CN102064532B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5917716A (en) * | 1997-02-21 | 1999-06-29 | Samsung Electronics Co., Ltd. | Switching mode power supplier having function of protecting circuit from abnormal voltage |
| US6229681B1 (en) * | 1998-03-07 | 2001-05-08 | Samsung Electronics Co., Ltd. | Switching mode power supply apparatus having a low voltage protection circuit |
| CN2552047Y (en) * | 2002-06-19 | 2003-05-21 | 深圳市跨宏实业有限公司 | Switch power with wide input voltage range |
| CN101083433A (en) * | 2006-06-01 | 2007-12-05 | 株式会社理光 | Switch electric source device |
| CN201307764Y (en) * | 2008-11-26 | 2009-09-09 | 深圳桑达国际电子器件有限公司 | Power supply circuit with overvoltage protection function |
Non-Patent Citations (2)
| Title |
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| 刘树林等.基于UC3842的开关电源输入过压保护电路研究.《铸造技术》.2005,第26卷(第10期), |
| 基于UC3842的开关电源输入过压保护电路研究;刘树林等;《铸造技术》;20051031;第26卷(第10期);第876-878页 * |
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Address after: Shenzhen Nanshan District City, Guangdong province 518108 industrial park outside the small pine Tai Bai Lu Bai mang mulberry 6 layer Applicant after: MOSO Power Supply Technology Co., Ltd. Address before: Shenzhen Nanshan District City, Guangdong province 518108 industrial park outside the small pine Tai Bai Lu Bai mang mulberry 6 layer Applicant before: Shenzhen MoSo Power Supply Technology Co., Ltd. |
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Free format text: CORRECT: APPLICANT; FROM: SHENZHEN MOSO POWER SUPPLY TECHNOLOGY CO., LTD. TO: MOSO POWER SUPPLY TECHNOLOGY CO., LTD. |
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