CN203896187U - Control circuit of switching-mode power supply - Google Patents
Control circuit of switching-mode power supply Download PDFInfo
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- CN203896187U CN203896187U CN201420191896.1U CN201420191896U CN203896187U CN 203896187 U CN203896187 U CN 203896187U CN 201420191896 U CN201420191896 U CN 201420191896U CN 203896187 U CN203896187 U CN 203896187U
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Abstract
The utility model provides a control circuit of a switching-mode power supply. The control circuit comprises a rectification filter circuit, a drive circuit, a switching circuit, a current detection circuit, a voltage feedback circuit and a logic control circuit. The output end of the drive circuit is connected with the switching circuit. The output end of the switching circuit is connected with the current detection circuit and the voltage feedback circuit. The output ends of the voltage feedback circuit and the current detection circuit are connected with the logic control circuit. The output end of the logic control circuit is connected with the drive circuit. As the control circuit of the switching-mode power supply comprises voltage feedback and current feedback, the control circuit has quick transient response for change in output voltage and load. By arranging an overcurrent protection circuit, subharmonic oscillation of output of the switching-mode circuit is prevented, and thus impact current caused by subharmonic oscillation is prevented from damaging a switch tube, thereby improving circuit reliability and stability.
Description
Technical field
The utility model relates to power electronic system field, particularly a kind of control circuit of Switching Power Supply.
Background technology
Stabilized voltage power supply is a requisite part in portable type electronic product, according to different operation principles, can be divided into three kinds of linear power supply, Switching Power Supply and charge pump power supplies, wherein, Switching Power Supply is by a kind of power supply of control switch power tube turn-on and turn-off time regulated output voltage.
Switching Power Supply is converted to extraneous 220V to meet the direct current supply voltage that required by electronic product is wanted, Switching Power Supply great majority are all to adopt common PWM control mode design on the market at present, because the effect of Switching Power Supply is high voltage input and low-voltage output, in circuit, there are two variablees of electric current and voltage, adopt separately Voltage Feedback to control switching circuit, exist circuit unstable, can not effectively to switching circuit, control, make circuit output unstable.
Utility model content
The utility model, for the technical problem of above-mentioned existence, has proposed a kind of control circuit of Switching Power Supply, switching circuit is carried out to the FEEDBACK CONTROL of voltage and current, is circuit stable output.
The technical solution of the utility model is: a kind of control circuit of Switching Power Supply, comprise: current rectifying and wave filtering circuit, drive circuit, switching circuit, current detection circuit, voltage feedback circuit and logic control circuit form, the output of described drive circuit connects described switching circuit, the output of described switching circuit connects current detection circuit and voltage feedback circuit, the output of described voltage feedback circuit and current detection circuit is connected to logic control circuit, and the output of described logic control circuit connects described drive circuit.
Technical scheme is further: described current detection circuit is PWM comparator Q1, the negative input of described PWM comparator Q1 connects the output of described switching circuit, the output of described voltage feedback circuit is connected to the electrode input end of PWM amplifier Q1, and the output of described PWM comparator Q1 is connected to described logic control circuit.
Technical scheme is further: described voltage feedback circuit is comprised of sample circuit and error amplifier Q2, described sample circuit is comprised of resistance R 3 and resistance R 4,4 series connection are connected with the output of switching circuit described resistance R 3 with resistance R, the tie point of described resistance R 3 and resistance R 4 is sampling output, described sampling output connects described error amplifier Q2 negative input, the electrode input end of described error amplifier Q2 connects comparative voltage, and the output of described error amplifier Q2 connects the positive pole of described PWM comparator Q1.
Technical scheme is further: the output of described current rectifying and wave filtering circuit connects current foldback circuit; described current foldback circuit is comprised of thyristor V1, resistance R 1, resistance R 2 and capacitor C 1; the output of described current rectifying and wave filtering circuit connects the anode of thyristor V1; the negative electrode of described thyristor V1 is connected with switching circuit; one end of the gate pole contact resistance R1 of described thyristor V1; the other end of described resistance R 1 is connected to switching circuit, and the negative electrode of described thyristor V1 is by capacitor C 1 ground connection.
The beneficial effects of the utility model: the utility model is because the control circuit of Switching Power Supply comprises Voltage Feedback and current feedback; the variation of output voltage and load is had to transient response faster; by current foldback circuit is set; the larger impulse current of import and export generation subharmonic oscillation generation that prevents switching circuit causes damage to switching tube, improves the reliability and stability of circuit.
Accompanying drawing explanation
Fig. 1 is the control circuit circuit structure diagram of a kind of Switching Power Supply that the utility model proposes.
Embodiment
Referring to Fig. 1, it is the control circuit structure chart of a kind of Switching Power Supply that the utility model proposes.
As shown in Figure 1, a kind of control circuit of Switching Power Supply, comprise: current rectifying and wave filtering circuit, drive circuit, switching circuit, current detection circuit, voltage feedback circuit and logic control circuit form, the output of described drive circuit connects described switching circuit, the output of described switching circuit connects current detection circuit and voltage feedback circuit, the output of described voltage feedback circuit and current detection circuit is connected to logic control circuit, and the output of described logic control circuit connects described drive circuit.
Described current detection circuit is PWM comparator Q1, the negative input of described PWM comparator Q1 connects the output of described switching circuit, the output of described voltage feedback circuit is connected to the electrode input end of PWM amplifier Q1, and the output of described PWM comparator Q1 is connected to described logic control circuit.
Described voltage feedback circuit is comprised of sample circuit and error amplifier Q2, described sample circuit is comprised of resistance R 3 and resistance R 4,4 series connection are connected with the output of switching circuit described resistance R 3 with resistance R, the tie point of described resistance R 3 and resistance R 4 is sampling output, described sampling output connects described error amplifier Q2 negative input, the electrode input end of described error amplifier Q2 connects comparative voltage, and the output of described error amplifier Q2 connects the positive pole of described PWM comparator Q1.
In the utility model embodiment, described switching power source control circuit mainly contains two feedback control loops, be respectively current feedback and Voltage Feedback, by current detection circuit, the inductive current of the output of Switching Power Supply is detected, and inductive current is converted into voltage Vd, the voltage Vb of the output voltage of Simultaneous Switching power supply after by resistance R 3 and resistance R 4 dividing potential drops is input in error amplifier, error amplifier compares output Vc by Vb and reference voltage V a, and electrode input end Vc and the voltage Vd of PWM comparator compare.Each cycle is when start, switch conduction, and inductive current increases, electric current and voltage Vd rising, when Vd rises to Vc, the upset of PWM comparator, output drive signal Vp, after amplification by logic control and drive circuit, on-off switching tube, thus inductive current is declined.
The output of described current rectifying and wave filtering circuit connects current foldback circuit; described current foldback circuit is comprised of thyristor V1, resistance R 1, resistance R 2 and capacitor C 1; the output of described current rectifying and wave filtering circuit connects the anode of thyristor V1; the negative electrode of described thyristor V1 is connected with switching circuit; one end of the gate pole contact resistance R1 of described thyristor V1; the other end of described resistance R 1 is connected to switching circuit, and the negative electrode of described thyristor V1 is by capacitor C 1 ground connection.
In the utility model embodiment, the existing Voltage Feedback of control circuit due to Switching Power Supply, there is again current feedback, the variation of output voltage and load is had to transient response faster, but when the duty ratio of PWM comparator is greater than 50%, can there is subharmonic oscillation, when the moment that switching tube is opened, can produce larger impulse current, cause switching tube to damage.In power connection moment, input voltage is through rectifier bridge and filter capacitor output, by current-limiting resistance R1, capacitor C 1 is charged, surge current to power connection moment is shunted, when capacitor C 1 is charged to approximately 80% rated voltage, switching circuit is normally worked, and produces the triggering signal of thyristor V1 through the auxiliary winding of main transformer, make thyristor V1 conducting short circuit current limitation resistance R 1, now Switching Power Supply is in normal operating conditions.
Above the utility model is described in detail, has applied specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment is just for helping to understand method of the present utility model and core concept thereof; , for one of ordinary skill in the art, according to thought of the present utility model, all will change in specific embodiments and applications, in sum, this description should not be construed as restriction of the present utility model meanwhile.
Claims (4)
1. the control circuit of a Switching Power Supply, it is characterized in that, comprise: current rectifying and wave filtering circuit, drive circuit, switching circuit, current detection circuit, voltage feedback circuit and logic control circuit form, the output of described drive circuit connects described switching circuit, the output of described switching circuit connects current detection circuit and voltage feedback circuit, the output of described voltage feedback circuit and current detection circuit is connected to logic control circuit, and the output of described logic control circuit connects described drive circuit.
2. the control circuit of a kind of Switching Power Supply according to claim 1, it is characterized in that, described current detection circuit is PWM comparator Q1, the negative input of described PWM comparator Q1 connects the output of described switching circuit, the output of described voltage feedback circuit is connected to the electrode input end of PWM amplifier Q1, and the output of described PWM comparator Q1 is connected to described logic control circuit.
3. the control circuit of a kind of Switching Power Supply according to claim 2, it is characterized in that, described voltage feedback circuit is comprised of sample circuit and error amplifier Q2, described sample circuit is comprised of resistance R 3 and resistance R 4, 4 series connection are connected with the output of switching circuit described resistance R 3 with resistance R, the tie point of described resistance R 3 and resistance R 4 is sampling output, described sampling output connects described error amplifier Q2 negative input, the electrode input end of described error amplifier Q2 connects comparative voltage, the output of described error amplifier Q2 connects the positive pole of described PWM comparator Q1.
4. the control circuit of a kind of Switching Power Supply according to claim 1; it is characterized in that; the output of described current rectifying and wave filtering circuit connects current foldback circuit; described current foldback circuit is comprised of thyristor V1, resistance R 1, resistance R 2 and capacitor C 1; the output of described current rectifying and wave filtering circuit connects the anode of thyristor V1; the negative electrode of described thyristor V1 is connected with switching circuit; one end of the gate pole contact resistance R1 of described thyristor V1; the other end of described resistance R 1 is connected to switching circuit, and the negative electrode of described thyristor V1 is by capacitor C 1 ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420191896.1U CN203896187U (en) | 2014-04-18 | 2014-04-18 | Control circuit of switching-mode power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420191896.1U CN203896187U (en) | 2014-04-18 | 2014-04-18 | Control circuit of switching-mode power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203896187U true CN203896187U (en) | 2014-10-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
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| CN201420191896.1U Expired - Fee Related CN203896187U (en) | 2014-04-18 | 2014-04-18 | Control circuit of switching-mode power supply |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490506A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Hearing aid apparatus for the senior |
| CN107294379A (en) * | 2017-08-12 | 2017-10-24 | 厦门奇力微电子有限公司 | The linear voltage-stabilizing circuit and method of High Pressure Difference exchange input |
| CN107482586A (en) * | 2017-08-23 | 2017-12-15 | 苏州麦喆思科电子有限公司 | A kind of overload protecting circuit of Switching Power Supply |
| CN109818328A (en) * | 2019-03-19 | 2019-05-28 | 浪潮商用机器有限公司 | A kind of switch power over-voltage protection circuit |
-
2014
- 2014-04-18 CN CN201420191896.1U patent/CN203896187U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490506A (en) * | 2015-12-28 | 2016-04-13 | 青岛玻莱莫斯新材料技术有限公司 | Hearing aid apparatus for the senior |
| CN107294379A (en) * | 2017-08-12 | 2017-10-24 | 厦门奇力微电子有限公司 | The linear voltage-stabilizing circuit and method of High Pressure Difference exchange input |
| CN107294379B (en) * | 2017-08-12 | 2023-07-28 | 厦门奇力微电子有限公司 | Linear voltage stabilizing circuit and method for high-voltage difference alternating current input |
| CN107482586A (en) * | 2017-08-23 | 2017-12-15 | 苏州麦喆思科电子有限公司 | A kind of overload protecting circuit of Switching Power Supply |
| CN109818328A (en) * | 2019-03-19 | 2019-05-28 | 浪潮商用机器有限公司 | A kind of switch power over-voltage protection 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: 20141022 Termination date: 20150418 |
|
| EXPY | Termination of patent right or utility model |