CN210405253U - Control circuit of switch circuit - Google Patents
Control circuit of switch circuit Download PDFInfo
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- CN210405253U CN210405253U CN201921331874.XU CN201921331874U CN210405253U CN 210405253 U CN210405253 U CN 210405253U CN 201921331874 U CN201921331874 U CN 201921331874U CN 210405253 U CN210405253 U CN 210405253U
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Abstract
The utility model provides a switch circuit's control circuit, the main switch tube drain-source terminal voltage of sampling switch circuit obtains sampling signal, detects inductive current and obtains current detection signal, control circuit includes reference signal production circuit and comparison circuit, reference signal production circuit receives sampling signal, according to sampling signal obtains first reference signal, sampling signal's peak value is big more with first reference signal is the negative correlation; the comparison circuit receives the first reference signal and the current detection signal respectively, and when the current detection signal reaches the first reference signal, the comparison circuit outputs a control signal to control the main switching tube of the switching circuit to be switched off. The utility model discloses can prevent to carry out the excess temperature protection to the load because of the overheated damage that leads to of main switch pipe electric current too big.
Description
Technical Field
The utility model relates to a power electronics field, in particular to switch circuit's control circuit.
Background
As shown in fig. 1, a graph of the output characteristic of the main switch tube of the switch circuit in the prior art is illustrated, when the peak current of the main switch tube is large, the required drain-source voltage VDS of the main switch tube will be high, so that the temperature of the main switch tube will be high. Under the condition that the temperature of the main switching tube is high, a higher drain-source voltage VDS is needed to maintain the stability of the peak current of the main switching tube, so that the temperature of the main switching tube is higher. The whole process is a positive feedback control, and the main switching tube is damaged finally.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a switch circuit's control circuit for solve the problem that the main switch pipe current that prior art exists is too big and the main switch pipe that leads to damages.
In order to achieve the above object, the utility model provides a switch circuit's control circuit, sampling switch circuit's main switch tube drain-source terminal voltage obtains sampling signal, detects inductive current and obtains the current detection signal, control circuit includes:
the reference signal generating circuit is used for receiving the sampling signal and obtaining a first reference signal according to the sampling signal, and the peak value of the sampling signal is in negative correlation with the first reference signal;
and the comparison circuit receives the first reference signal and the current detection signal respectively, and outputs a control signal to control the main switching tube of the switching circuit to be switched off when the current detection signal reaches the first reference signal.
Optionally, the control circuit further includes an over-temperature protection circuit, which receives the sampling signal and the first voltage, and outputs a difference between the sampling signal and the first voltage to control the turn-off time of a main switching tube of the switching circuit; the difference value between the sampling signal and the first voltage is positively correlated with the turn-off time of the main switching tube; sampling the temperature of the control circuit or the main switching tube to obtain the first voltage, wherein the first voltage and the temperature of the control circuit are in negative correlation.
Optionally, the reference signal generating circuit includes a first comparator, a first switching tube and a first capacitor, when a main switching tube is in a conducting state, a first input end of the first comparator receives the sampling signal, an output end of the first comparator is connected to a control end of the first switching tube, a first end of the first switching tube is connected to a high potential end, a second end of the first switching tube is connected to a first end of the first capacitor, a second end of the first capacitor is grounded, a second input end of the first comparator is connected to a common end of the first switching tube and the first capacitor, and a voltage of the first capacitor is a peak value of the sampling signal;
when the main switching tube is in a conducting state, the current flowing through the first switching tube charges the first capacitor; and under the off state of the main switching tube, the first capacitor discharges.
Optionally, the control circuit further includes an arithmetic circuit, the arithmetic circuit receives the first capacitor voltage and the first voltage, the arithmetic circuit outputs the first reference signal, and the first reference signal is a difference between the first voltage and the first capacitor voltage.
Compared with the prior art, the utility model has the advantages of it is following: sampling the drain-source end voltage of a main switching tube of a switching circuit to obtain a sampling signal, detecting the inductive current to obtain a current detection signal, and obtaining a first reference signal according to the sampling signal, wherein the peak value of the sampling signal is in negative correlation with the first reference signal; and when the current detection signal reaches the first reference signal, the main switching tube of the switching circuit is controlled to be switched off. The utility model discloses can prevent to damage because of the main switch pipe that the too big main switch pipe's that leads to of electric current that flows through main switch pipe, can also increase system reliability, prevent that the system from damaging by the excess temperature.
Drawings
FIG. 1 is a graph of the output characteristics of a main switching tube of a prior art switching circuit;
fig. 2 is a control block diagram of the switching circuit of the present invention;
FIG. 3 is a schematic diagram of the reference signal generating circuit of FIG. 2;
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to only these embodiments. The present invention covers any alternatives, modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.
In the following description of the preferred embodiments of the present invention, specific details are set forth in order to provide a thorough understanding of the present invention, and it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.
The invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are simplified and in non-precise proportion, so as to facilitate and clearly assist in explaining the embodiments of the present invention.
As shown in fig. 2, the utility model discloses a control block diagram of switch circuit, including drain-source voltage sampling circuit U01, inductive current sampling circuit U02, reference signal production circuit U03, comparison circuit U04, excess temperature protection circuit U05, drive circuit U06 and first control circuit U07, drain-source voltage sampling circuit U01 obtains sampling signal VDS at the drain-source voltage of the main switch tube among the sampling switch circuit when the main switch tube switches on; the inductor current sampling circuit U02 samples the inductor current of the switching circuit to obtain a current detection signal VCS. The reference signal generating circuit U03 receives the sampling signal VDS, and obtains a first reference signal VREF according to the sampling signal VDS, where the larger the peak value of the sampling signal is, the smaller the first reference signal VREF is. The comparison circuit U04 receives the first reference signal VREF and the current detection signal VCS, respectively, and when the current detection signal VCS reaches the first reference signal VREF, the comparison circuit U04 outputs a first control signal V _ ton to control the main switching tube to be turned off. The over-temperature protection circuit U05 receives the sampling signal VDS and the first voltage VC1, and outputs a difference value between the sampling signal VDS and the first voltage VC1 to control the turn-off time of a main switching tube of the switching circuit, wherein the difference value is larger. The temperature of sampling control circuit or main switch pipe obtains temperature sampling signal T, first control circuit U07 receives temperature sampling signal T, outputs first voltage VC1, temperature sampling signal T and first voltage VC1 are the negative correlation. The driving circuit U06 receives the first control signal V _ ton and the second control signal V _ toff, and outputs a driving signal to control the on/off of the main switching tube. The drain-source voltage and the inductance current peak value change simultaneously, so that the system response can be slowed down, and the phenomenon of light shaking of an LED load is prevented. Since the drain-source voltage may be higher, the ability to output current may also be higher.
As shown in fig. 3, a schematic diagram of the reference signal generating circuit in fig. 2 is illustrated, and the reference signal generating circuit includes a first comparator U101, a first switching tube M1, a current source I1, a first capacitor C1, a switch k1, a switch k2, an arithmetic circuit U101, a second comparator U103, and a zero-crossing detection circuit U104. When the main switch tube of the switch circuit is turned on, the switch k1 is closed, the non-inverting input end of the first comparator U101 receives the sampling signal VDS of the drain-source voltage, the output end of the first comparator U101 is connected with the control end of the first switch tube M1, the first end of the first switch tube M1 is connected with the current source I1, the second end of the first switch tube M1 is connected with the first end of the first capacitor C1, the second end of the first capacitor C1 is grounded, and the inverting input end of the first comparator U101 is connected with the common end of the first switch tube M1 and the first capacitor C1. When the voltage on the first capacitor C1 is less than the sampling signal VDS, the first switch M1 is turned on, the first current source I1 outputs a first current to charge the first capacitor C1 until the voltage on the first capacitor C1 reaches the maximum value of the sampling signal VDS, and then the first switch M1 is turned off. The switch k2 is connected in parallel with the first capacitor C1, when the main switch tube is turned off, the switch k2 is turned off, and the first capacitor C1 discharges. The operation circuit U102 receives the voltage on the first capacitor C1 and the first voltage V1, and outputs a first reference signal VREF, where the first reference signal VREF is the difference between the first voltage V1 and the voltage on the first capacitor C1.
Although the embodiments have been described and illustrated separately, it will be apparent to those skilled in the art that some common techniques may be substituted and integrated between the embodiments, and reference may be made to one of the embodiments not explicitly described, or to another embodiment described.
The above-described embodiments do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the above-described embodiments should be included in the protection scope of the technical solution.
Claims (4)
1. The utility model provides a switch circuit's control circuit, the main switch tube drain-source terminal voltage of sampling switch circuit obtains the sampling signal, detects the inductive current and obtains current detection signal which characterized in that: comprises that
The reference signal generating circuit is used for receiving the sampling signal and obtaining a first reference signal according to the sampling signal, and the peak value of the sampling signal and the first reference signal are in negative correlation;
and the comparison circuit receives the first reference signal and the current detection signal respectively, and outputs a control signal to control the main switching tube of the switching circuit to be switched off when the current detection signal reaches the first reference signal.
2. The control circuit of the switching circuit according to claim 1, characterized in that: the control circuit also comprises an over-temperature protection circuit which respectively receives the sampling signal and the first voltage and outputs the difference value of the sampling signal and the first voltage to control the turn-off time of a main switching tube of the switching circuit; the difference value between the sampling signal and the first voltage is positively correlated with the turn-off time of the main switching tube; sampling the temperature of the control circuit or the main switching tube to obtain the first voltage, wherein the first voltage and the temperature are in negative correlation.
3. The control circuit of the switching circuit according to claim 2, characterized in that: the reference signal generating circuit comprises a first comparator, a first switch tube and a first capacitor, wherein in the on state of a main switch tube, a first input end of the first comparator receives the sampling signal, an output end of the first comparator is connected with a control end of the first switch tube, a first end of the first switch tube is connected with a high potential end, a second end of the first switch tube is connected with a first end of the first capacitor, a second end of the first capacitor is grounded, a second input end of the first comparator is connected with a common end of the first switch tube and the first capacitor, and the voltage of the first capacitor is the peak value of the sampling signal;
when the main switching tube is in a conducting state, the current flowing through the first switching tube charges the first capacitor; and under the off state of the main switching tube, the first capacitor discharges.
4. The control circuit of the switching circuit according to claim 3, characterized in that: the control circuit further comprises an arithmetic circuit, the arithmetic circuit receives the first capacitor voltage and the first voltage, the arithmetic circuit outputs the first reference signal, and the first reference signal is a difference value between the first voltage and the first capacitor voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921331874.XU CN210405253U (en) | 2019-08-16 | 2019-08-16 | Control circuit of switch circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921331874.XU CN210405253U (en) | 2019-08-16 | 2019-08-16 | Control circuit of switch circuit |
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| Publication Number | Publication Date |
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| CN210405253U true CN210405253U (en) | 2020-04-24 |
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| CN201921331874.XU Active CN210405253U (en) | 2019-08-16 | 2019-08-16 | Control circuit of switch circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110504951A (en) * | 2019-08-16 | 2019-11-26 | 杰华特微电子（杭州）有限公司 | The control circuit and control method of switching circuit |
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2019
- 2019-08-16 CN CN201921331874.XU patent/CN210405253U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110504951A (en) * | 2019-08-16 | 2019-11-26 | 杰华特微电子（杭州）有限公司 | The control circuit and control method of switching circuit |
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Address after: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee after: Jiehuate Microelectronics Co.,Ltd. Address before: Room 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030 Patentee before: JOULWATT TECHNOLOGY (HANGZHOU) Co.,Ltd. |
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| CP01 | Change in the name or title of a patent holder |