CN202840488U - Switch power control circuit with short circuit protection - Google Patents
Switch power control circuit with short circuit protection Download PDFInfo
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- CN202840488U CN202840488U CN 201220514998 CN201220514998U CN202840488U CN 202840488 U CN202840488 U CN 202840488U CN 201220514998 CN201220514998 CN 201220514998 CN 201220514998 U CN201220514998 U CN 201220514998U CN 202840488 U CN202840488 U CN 202840488U
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- optocoupler
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Abstract
The utility model relates to a switch power control circuit with short circuit protection. The switch power control circuit comprises a switch pipe, a control circuit, a secondary control circuit, a starting circuit and an optical coupling circuit, wherein the control circuit is used for controlling connection and disconnection of a main wounding of a transformer, the secondary control circuit is used for detecting output voltage and current of the transformer, the starting circuit is used for starting the primary main wounding of the transformer, and the optical coupling circuit is used for providing a feedback signal of the output voltage of the transformer for the switch pipe and the control circuit. The switch power control circuit with the short circuit protection achieves reliable short circuit protection of a switch power supply and is simple in structure and low in manufacture cost.
Description
Technical field
The utility model relates to electronic technology field, relates in particular to a kind of Switching Power Supply control circuit that carries short-circuit protection.
Background technology
In Switching Power Supply is used, elementary if the PWM controller is positioned at, and output parameter such as output voltage, electric current need in secondary detection, at this moment can be delivered to elementary PWM controller to secondary control signal by optocoupler usually.Such as Fig. 1, be the Switching Power Supply control circuit theory diagram of a typical circuit of reversed excitation (Flyback), secondary controller can be realized the functions such as constant voltage, constant current by the elementary PWM controller of optocoupler control according to output voltage, electric current that its detection draws.For example, (Vsen) is higher than voltage setting value when output voltage, or output current (Isen) is when being higher than current setting value, the control level Vc of secondary controller can reduce, thereby the electric current of the optocoupler of flowing through (VL) increases, and the light-emitting diode luminance in the optocoupler (VL) increases, the corresponding increase of triode conducting degree in the optocoupler (VL), thereby the feedback level of elementary PWM controller (FB) raises, and the PWM duty ratio reduces, and final output voltage, electric current are stabilized in set point.But under the situation of output short-circuit, fail to make correct control, because in the time of output short-circuit, the power supply of the power supply of secondary controller (SVcc) and optocoupler (VL) can be lost, optocoupler (VL) is in closed condition, the feedback level of elementary PWM controller (FB) fails to raise, elementary PWM controller with maximum duty cycle output, has the risk that causes power supply apparatus to damage on the contrary.
The utility model content
The purpose of this utility model is as overcoming the defective of prior art, and a kind of Switching Power Supply control circuit that carries short-circuit protection is provided.
For achieving the above object, the utility model is by the following technical solutions: a kind of Switching Power Supply control circuit that carries short-circuit protection also comprises:
Switching tube and control circuit are used for connection and the shutoff of the elementary main winding of control transformer; Secondary control circuit is used for output voltage, current detecting to transformer; Start-up circuit in order to the startup of the elementary main winding of transformer, and photoelectric coupled circuit, is used for providing to described switching tube and control circuit the feedback signal of the output voltage of transformer; The control level output is connected optocoupler internal body diodes negative pole end ground connection on the secondary controller in the described secondary control circuit with the optocoupler internal body diodes positive terminal of photoelectric coupled circuit through the first resistance; The collector electrode of the inner triode of the optocoupler of photoelectric coupled circuit is connected with the PWM controller feedback level end of switching tube and control circuit, the grounded emitter of the inner triode of the optocoupler of photoelectric coupled circuit; The input of described start-up circuit is connected with the elementary auxiliary winding output of transformer, and the output of described start-up circuit is connected with PWM controller feedback level end in switching tube and the control circuit.
Described start-up circuit comprises voltage-stabiliser tube and the second resistance, the auxiliary winding output of primary is connected with the negative pole of voltage-stabiliser tube, the positive pole of voltage-stabiliser tube is connected with an end of the second resistance, and the other end of the second resistance is connected with PWM controller feedback level end in described switching tube and the control circuit.
Also comprise power converter circuit, described power converter circuit is the arbitrary circuit in circuit of reversed excitation, single-stage pfc circuit, forward converter, bridge circuit or the LLC resonant circuit.
1), by changing the feedback phase mode the utility model beneficial effect compared with prior art is:, realize the reliable short-circuit protection of Switching Power Supply; 2) simple in structure, low cost of manufacture.
Description of drawings
Fig. 1 is the Switching Power Supply control circuit theory diagram of prior art;
Fig. 2 is the Switching Power Supply control circuit theory diagram of the utility model preferred embodiment.
Embodiment
In order to more fully understand technology contents of the present utility model, below in conjunction with specific embodiment the technical solution of the utility model is further introduced and explanation.
As shown in Figure 2, the Switching Power Supply control circuit theory diagram for the utility model preferred embodiment comprises transformer (TF), also comprises switching tube and control circuit 1, is used for connection and the shutoff of the elementary main winding (N1) of control transformer (TF); Secondary control circuit 2 is used for output voltage, current detecting to transformer (TF); And photoelectric coupled circuit 3, be used for providing to described switching tube and control circuit the feedback signal of the output voltage of transformer (TF); Control level output (Vc) is connected optocoupler (VL) internal body diodes negative pole end ground connection through the first electricity group (R1) on the secondary controller in the described secondary control circuit 2 with optocoupler (VL) the internal body diodes positive terminal of photoelectric coupled circuit (3); The collector electrode of the inner triode of the optocoupler of photoelectric coupled circuit 3 (VL) is connected the grounded emitter of the interior triode of the optocoupler of photoelectric coupled circuit 3 (VL) with switching tube and control circuit 1 interior PWM controller feedback level end (FB).The phase place of optocoupler (VL) is from original: the optocoupler of flowing through (VL) interior light emitting diodes electric current reduces the duty ratio of PWM controller when increasing, change into: the optocoupler of flowing through (VL) interior light emitting diodes electric current reduces the duty ratio of PWM controller when reducing.Like this; when output short-circuit; the power supply (SVcc) of dimension level controller and the power supply of optocoupler (VL) are lost; optocoupler (VL) is in closed condition; the feedback level of PWM controller (FB) raises; PWM controller duty ratio is reduced to naturally closes, and then closes the elementary main winding of transformer (TF), thereby has protected power supply.Simultaneously, select still to keep original circuit function by suitable control phase.When realizing constant voltage, constant current function, as shown in Figure 2, when output voltage (Vsen) is higher than voltage setting value or output current (Isen) when being higher than current setting value, control level goes out end (Vc) meeting reduction on the secondary controller, thereby the electric current of the optocoupler of flowing through (VL) reduces, light-emitting diode luminance in the optocoupler (VL) reduces, the corresponding reduction of triode conducting degree in the optocoupler (VL), thereby the feedback level end (FB) of PWM controller raises, the PWM duty ratio reduces, and final output voltage, electric current are stabilized in set point.
Start-up circuit 4 comprises voltage-stabiliser tube (ZD) and the second resistance (R2), the elementary auxiliary winding of transformer (TF) (N2) output is connected with the negative pole of voltage-stabiliser tube (ZD), the positive pole of voltage-stabiliser tube (ZD) is connected with an end of the second resistance (R2), and the other end of the second resistance (R2) is connected with described switching tube and control circuit 1 interior PWM controller feedback level end (FB).When power initiation, when the elementary auxiliary winding of transformer (TF) (N2) when output end voltage is not high enough, (ZD) do not puncture, the feedback level end (FB) of PWM controller is not gone up bias current, it is low level, PWM controller output maximum duty cycle, the elementary main winding (N1) of transformer (TF) and elementary auxiliary winding (N2) supply power voltage can raise simultaneously like this, until (ZD) breakdown, the upper bias current of the feedback level end (FB) of PWM controller is set up, at this moment the power supply of secondary controller (SVcc) is also enough high, and it is normal that whole control loop recovers, and power supply is started.
Circuit of reversed excitation comprises diode (D) and electric capacity (C), the positive pole of described diode (D) is connected with the elementary auxiliary winding of transformer (TF) (N2) output, the negative pole of diode (D) is connected with the negative pole of voltage-stabiliser tube (ZD), one end of electric capacity (C) is connected with the negative pole of diode (D), the other end ground connection of electric capacity (C).
The above only further specifies technology contents of the present utility model with embodiment; so that the reader is more readily understood; but do not represent execution mode of the present utility model and only limit to this, any technology of doing according to the utility model is extended or recreation, all is subjected to protection of the present utility model.
Claims (3)
1. a Switching Power Supply control circuit that carries short-circuit protection is characterized in that, comprising:
Switching tube and control circuit are used for connection and the shutoff of the elementary main winding of control transformer;
Secondary control circuit is used for output voltage, current detecting to transformer;
Start-up circuit, in order to the startup of the elementary main winding of transformer, and
Photoelectric coupled circuit is used for providing to described switching tube and control circuit the feedback signal of the output voltage of described transformer;
The control level output is connected optocoupler internal body diodes negative pole end ground connection on the secondary controller in the described secondary control circuit with the optocoupler internal body diodes positive terminal of photoelectric coupled circuit through the first resistance; The collector electrode of the inner triode of the optocoupler of photoelectric coupled circuit is connected with the PWM controller feedback level end of switching tube and control circuit, the grounded emitter of the inner triode of the optocoupler of photoelectric coupled circuit; The input of described start-up circuit is connected with the elementary auxiliary winding output of transformer, and the output of described start-up circuit is connected with PWM controller feedback level end in switching tube and the control circuit.
2. the Switching Power Supply control circuit that carries short-circuit protection according to claim 1; it is characterized in that; described start-up circuit comprises voltage-stabiliser tube and the second resistance; the auxiliary winding output of primary is connected with the negative pole of voltage-stabiliser tube; the positive pole of voltage-stabiliser tube is connected with an end of the second resistance, and the other end of the second resistance is connected with PWM controller feedback level end in described switching tube and the control circuit.
3. the Switching Power Supply control circuit that carries short-circuit protection according to claim 1 and 2; it is characterized in that; also comprise power converter circuit, described power converter circuit is the arbitrary circuit in circuit of reversed excitation, single-stage pfc circuit, forward converter, bridge circuit or the LLC resonant circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220514998 CN202840488U (en) | 2012-10-09 | 2012-10-09 | Switch power control circuit with short circuit protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220514998 CN202840488U (en) | 2012-10-09 | 2012-10-09 | Switch power control circuit with short circuit protection |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202840488U true CN202840488U (en) | 2013-03-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220514998 Expired - Fee Related CN202840488U (en) | 2012-10-09 | 2012-10-09 | Switch power control circuit with short circuit protection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202840488U (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104578826A (en) * | 2014-12-31 | 2015-04-29 | 上海新进半导体制造有限公司 | Switch power supply and control method for providing constant voltage and constant current in switch power supply |
| CN105790564A (en) * | 2016-04-13 | 2016-07-20 | 深圳市赢新光电发展有限公司 | Starting circuit and switch power supply |
| CN106533179A (en) * | 2015-09-11 | 2017-03-22 | 万国半导体(开曼)股份有限公司 | Voltage converter |
| CN106684814A (en) * | 2017-03-23 | 2017-05-17 | 广州市爱浦电子科技有限公司 | High-precision normal-shock switch power output overvoltage protection circuit |
| CN108199584A (en) * | 2017-12-25 | 2018-06-22 | 北京精密机电控制设备研究所 | A kind of forward power circuit of multitube series connection |
| CN112968425A (en) * | 2021-04-30 | 2021-06-15 | 重庆斯微奇电子技术有限公司 | Secondary short-circuit protection circuit of switching power supply |
| CN113451994A (en) * | 2021-06-30 | 2021-09-28 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| CN115764811A (en) * | 2022-11-14 | 2023-03-07 | 长城电源技术(深圳)有限公司 | Short-circuit protection circuit and switching power supply with same |
-
2012
- 2012-10-09 CN CN 201220514998 patent/CN202840488U/en not_active Expired - Fee Related
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104578826B (en) * | 2014-12-31 | 2018-10-19 | 上海新进半导体制造有限公司 | Switching Power Supply and the method that constant pressure and current constant control are provided in Switching Power Supply |
| CN104578826A (en) * | 2014-12-31 | 2015-04-29 | 上海新进半导体制造有限公司 | Switch power supply and control method for providing constant voltage and constant current in switch power supply |
| CN106533179A (en) * | 2015-09-11 | 2017-03-22 | 万国半导体(开曼)股份有限公司 | Voltage converter |
| CN106533179B (en) * | 2015-09-11 | 2019-04-26 | 万国半导体(开曼)股份有限公司 | Electric pressure converter |
| CN105790564A (en) * | 2016-04-13 | 2016-07-20 | 深圳市赢新光电发展有限公司 | Starting circuit and switch power supply |
| CN105790564B (en) * | 2016-04-13 | 2018-05-08 | 深圳茂硕电子科技有限公司 | A kind of start-up circuit and Switching Power Supply |
| CN106684814A (en) * | 2017-03-23 | 2017-05-17 | 广州市爱浦电子科技有限公司 | High-precision normal-shock switch power output overvoltage protection circuit |
| CN108199584A (en) * | 2017-12-25 | 2018-06-22 | 北京精密机电控制设备研究所 | A kind of forward power circuit of multitube series connection |
| CN108199584B (en) * | 2017-12-25 | 2020-07-14 | 北京精密机电控制设备研究所 | Multi-tube series forward power circuit |
| CN112968425A (en) * | 2021-04-30 | 2021-06-15 | 重庆斯微奇电子技术有限公司 | Secondary short-circuit protection circuit of switching power supply |
| CN112968425B (en) * | 2021-04-30 | 2023-02-21 | 重庆斯微奇电子技术有限公司 | Secondary short-circuit protection circuit of switching power supply |
| CN113451994A (en) * | 2021-06-30 | 2021-09-28 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| CN113451994B (en) * | 2021-06-30 | 2024-03-15 | 科华数据股份有限公司 | Optical coupler failure protection circuit and power supply system |
| CN115764811A (en) * | 2022-11-14 | 2023-03-07 | 长城电源技术(深圳)有限公司 | Short-circuit protection circuit and switching power supply with same |
| CN115764811B (en) * | 2022-11-14 | 2024-03-29 | 长城电源技术(深圳)有限公司 | Short-circuit protection circuit and switching power supply with same |
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| 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: 20130327 Termination date: 20141009 |
|
| EXPY | Termination of patent right or utility model |