CN110504951A - The control circuit and control method of switching circuit - Google Patents
The control circuit and control method of switching circuit Download PDFInfo
- Publication number
- CN110504951A CN110504951A CN201910758057.0A CN201910758057A CN110504951A CN 110504951 A CN110504951 A CN 110504951A CN 201910758057 A CN201910758057 A CN 201910758057A CN 110504951 A CN110504951 A CN 110504951A
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- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000001514 detection method Methods 0.000 claims abstract description 19
- 238000005070 sampling Methods 0.000 claims abstract description 18
- 230000002596 correlated effect Effects 0.000 claims abstract description 14
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 claims abstract description 10
- 230000001939 inductive effect Effects 0.000 claims abstract description 9
- 239000003990 capacitor Substances 0.000 claims description 29
- 230000005611 electricity Effects 0.000 claims description 2
- 230000001012 protector Effects 0.000 abstract 1
- 230000003685 thermal hair damage Effects 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 206010044565 Tremor Diseases 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/08—Modifications for protecting switching circuit against overcurrent or overvoltage
- H03K17/082—Modifications for protecting switching circuit against overcurrent or overvoltage by feedback from the output to the control circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/14—Modifications for compensating variations of physical values, e.g. of temperature
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- Electronic Switches (AREA)
Abstract
The present invention proposes the control circuit and control method of a kind of switching circuit, the main switch leakage source voltage terminal of sampling switch circuit obtains sampled signal, detection inductive current obtains current detection signal, the control circuit includes reference signal generation circuit and comparison circuit, the reference signal generation circuit receives the sampled signal, the first reference signal is obtained according to the sampled signal, the peak value of the sampled signal is bigger negatively correlated with first reference signal；The comparison circuit receives first reference signal and current detection signal respectively, when the current detection signal reaches first reference signal, the main switch shutdown of the comparison circuit output control signal control switch circuit.The present invention can prevent because main switch electric current it is excessive caused by cross cause thermal damage, can also to load carry out overheat protector.
Description
Technical field
The present invention relates to field of power electronics, in particular to the control circuit and control method of a kind of switching circuit.
Background technique
As shown in Figure 1, prior art switching circuit main switch output characteristic curve figure is illustrated, when the peak of main switch
When value electric current is larger, required main switch drain-source voltage VDS can be higher, so that the temperature of main switch can be higher.In master
In the higher situation of switching tube temperature, to maintain the peak point current of main switch to stablize, and higher drain-source voltage is needed
VDS, to make the temperature of main switch higher again.Whole process is a positive feedback control, eventually makes main switch
Damage.
Summary of the invention
The object of the present invention is to provide a kind of control circuit of switching circuit and control methods, deposit for solving the prior art
Main switch electric current it is excessive caused by main switch damage the problem of.
To achieve the above object, the present invention provides a kind of control circuit of switching circuit, the master of sampling switch circuit is opened
It closes pipe leakage source voltage terminal and obtains sampled signal, detection inductive current obtains current detection signal, and the control circuit includes:
Reference signal generation circuit receives the sampled signal, obtains the first reference signal, institute according to the sampled signal
Peak value and first reference signal for stating sampled signal are negatively correlated；
Comparison circuit receives first reference signal and current detection signal respectively, when the current detection signal reaches
When to first reference signal, the main switch shutdown of the comparison circuit output control signal control switch circuit.
Optionally, the control circuit further includes thermal-shutdown circuit, receives the sampled signal and first voltage respectively,
The difference of the sampled signal and first voltage is exported with the turn-off time of the main switch of control switch circuit；The sampling letter
Number and the difference of first voltage and the turn-off time of main switch be positively correlated；Sample the temperature of the control circuit or main switch
For degree to obtain the first voltage, the temperature of the first voltage and the control circuit is negatively correlated.
Optionally, the reference signal generation circuit includes first comparator, first switch tube and first capacitor, main switch
Under pipe on state, the first input end of the first comparator receives the sampled signal, the output of the first comparator
End connects the control terminal of the first switch tube, and the first end of the first switch tube connects hot end, the first switch
The first end of the second end connection first capacitor of pipe, the second end ground connection of the first capacitor, the second of the first comparator
Input terminal connects the common end of the first switch tube and the first capacitor, and the first capacitor voltage is the sampled signal
Peak value；
Under main switch on state, the electric current for flowing through the first switch tube charges to the first capacitor；Main switch
Under pipe off state, the first capacitor electric discharge.
Optionally, the control circuit further includes computing circuit, the computing circuit receive the first capacitor voltage and
First voltage, the computing circuit export first reference signal, and first reference signal is the first voltage and institute
State the difference of first capacitor voltage.
The present invention also provides a kind of control method of switching circuit, the main switch leakage source voltage terminal of sampling switch circuit is obtained
To sampled signal, detects inductive current and obtain current detection signal, the first reference signal is obtained according to the sampled signal, it is described
The peak value of sampled signal is bigger, and first reference signal is smaller；When the current detection signal reaches described first with reference to letter
Number when, control switch circuit main switch shutdown.
Optionally, the sampled signal and first voltage are made into difference to control the turn-off time of main switch, the sampling
The turn-off time of the main switch of the difference and switching circuit of signal and first voltage is positively correlated；The master of sampling switch circuit opens
The temperature of pipe is closed to obtain the first voltage, the first voltage and the temperature are negatively correlated.
Compared with prior art, the invention has the following advantages that the main switch leakage source voltage terminal of sampling switch circuit obtains
To sampled signal, detects inductive current and obtain current detection signal, the first reference signal is obtained according to the sampled signal, it is described
The peak value of sampled signal and first reference signal are negatively correlated；When the current detection signal reaches described first with reference to letter
Number when, control switch circuit main switch shutdown.The present invention can prevent from causing because the electric current for flowing through main switch is excessive
Main switch damage, system reliability can also be increased, anti-locking system excess temperature damage.
Detailed description of the invention
Fig. 1 is the output characteristic curve figure of prior art switching circuit main switch；
Fig. 2 is the control block diagram of switching circuit of the present invention；
Fig. 3 is the schematic diagram of reference signal generation circuit in Fig. 2；
Specific embodiment
The preferred embodiment of the present invention is described in detail below in conjunction with attached drawing, but the present invention is not restricted to these
Embodiment.The present invention covers any substitution made in the spirit and scope of the present invention, modification, equivalent method and scheme.
In order to make the public have thorough understanding to the present invention, it is described in detail in the following preferred embodiment of the present invention specific
Details, and the present invention can also be understood completely in description without these details for a person skilled in the art.
The present invention is more specifically described by way of example referring to attached drawing in the following passage.It should be noted that attached drawing is adopted
With more simplified form and using non-accurate ratio, to convenient, the lucidly aid illustration embodiment of the present invention the mesh
's.
As shown in Fig. 2, illustrating the control block diagram of switching circuit of the present invention, including drain-source voltage sample circuit U01, inductance
Current sampling circuit U02, reference signal generation circuit U03, comparison circuit U04, thermal-shutdown circuit U05, driving circuit U06 and
The leakage of first control circuit U07, drain-source voltage sample circuit the U01 main switch in sampling switch circuit when main switch is connected
Source voltage obtains sampled signal VDS；The inductive current of 02 sampling switch circuit of inductive current sampling circuit U obtains current detecting
Signal VCS.The reference signal generation circuit U03 receives the sampled signal VDS, obtains the according to the sampled signal VDS
One reference signal VREF, the peak value of the sampled signal is bigger, and the first reference signal VREF is smaller.The comparison circuit
U04 receives the first reference signal VREF and current detection signal VCS respectively, when the current detection signal VCS reaches institute
When stating the first reference signal VREF, the comparison circuit U04 output first control signal V_ton control main switch shutdown.Institute
It states thermal-shutdown circuit U05 and receives the sampled signal VDS and first voltage VC1, export the electricity of the sampled signal VDS and first
The difference of VC1 is pressed, with the main switch turn-off time of control switch circuit, the difference is bigger.Sampling control circuit or master open
The temperature for closing pipe obtains temperature sampling signal T, and the first control circuit U07 receives temperature sampling signal T, exports first voltage
VC1, the temperature sampling signal T and first voltage VC1 are negatively correlated.The driving circuit U06 receives the first control letter
Number V_ton and second control signal V_toff, output drive signal is to control main switch on-off.Leak source voltage terminal and
Inductive current peak changes simultaneously, can relieving system response, prevent LED load from occurring trembling lamp phenomenon.Since leakage source voltage terminal can
With higher, the ability for exporting electric current can also be higher.
As shown in figure 3, illustrating the schematic diagram of reference signal generation circuit in Fig. 2, including first comparator U101, first
Switching tube M1, current source I1, first capacitor C1, switch k1, switch k2, computing circuit U101, the second comparator U103, zero passage inspection
Slowdown monitoring circuit U104.In the conducting of switching circuit main switch, the non-inverting input terminal of switch k1 closure, first comparator U101 is received
The control terminal of the output end connection first switch tube M1 of the sampled signal VDS of drain-source voltage, first comparator U101, first switch
The first end of pipe M1 connects current source I1, the first end of the second end connection first capacitor C1 of first switch tube M1, first capacitor
The second end of C1 is grounded, and the inverting input terminal connection first switch tube M1's and first capacitor C1 of first comparator U101 is public
End.When voltage is less than sampled signal VDS on first capacitor C1, first switch tube M1 conducting, the first current source I1 output first
Electric current charges to first capacitor C1, until voltage reaches the maximum value of the sampled signal VDS on first capacitor C1, then, the
One switching tube M1 shutdown.Switch k2 and first capacitor C1 are in parallel, when main switch shutdown, switch k2 shutdown, and first capacitor C1
Electric discharge.Computing circuit U102 receives first capacitor C1 upper voltage and first voltage V1, exports the first reference signal VREF, and described the
One reference signal VREF is the difference of voltage on first voltage V1 and first capacitor C1.
Although embodiment is separately illustrated and is illustrated above, it is related to the common technology in part, in ordinary skill
Personnel apparently, can be replaced and integrate between the embodiments, be related to one of embodiment and the content recorded is not known, then
It can refer to another embodiment on the books.
Embodiments described above does not constitute the restriction to the technical solution protection scope.It is any in above-mentioned implementation
Made modifications, equivalent substitutions and improvements etc., should be included in the protection model of the technical solution within the spirit and principle of mode
Within enclosing.
Claims (6)
1. the main switch leakage source voltage terminal of a kind of control circuit of switching circuit, sampling switch circuit obtains sampled signal, examine
It surveys inductive current and obtains current detection signal, it is characterised in that: including
Reference signal generation circuit receives the sampled signal, obtains the first reference signal according to the sampled signal, described to adopt
The peak value of sample signal and first reference signal are negatively correlated；
Comparison circuit receives first reference signal and current detection signal respectively, when the current detection signal reaches institute
When stating the first reference signal, the main switch shutdown of the comparison circuit output control signal control switch circuit.
2. the control circuit of switching circuit according to claim 1, it is characterised in that: the control circuit further includes excess temperature
Circuit is protected, the sampled signal and first voltage is received respectively, exports the difference of the sampled signal and first voltage to control
The turn-off time of the main switch of switching circuit processed；When the shutdown of the difference and main switch of the sampled signal and first voltage
Between be positively correlated；The temperature of the control circuit or main switch is sampled to obtain the first voltage, the first voltage and
The temperature is negatively correlated.
3. the control circuit of switching circuit according to claim 2, it is characterised in that: the reference signal generation circuit packet
Include first comparator, first switch tube and first capacitor, under main switch on state, the first input of the first comparator
End receives the sampled signal, and the output end of the first comparator connects the control terminal of the first switch tube, and described first
The first end of switching tube connects hot end, the first end of the second end connection first capacitor of the first switch tube, and described the
The second end of one capacitor is grounded, and the second input terminal of the first comparator connects the first switch tube and the first capacitor
Common end, the first capacitor voltage be the sampled signal peak value；
Under main switch on state, the electric current for flowing through the first switch tube charges to the first capacitor；Main switch closes
Under disconnected state, the first capacitor electric discharge.
4. the control circuit of switching circuit according to claim 3, it is characterised in that: the control circuit further includes operation
Circuit, the computing circuit receive the first capacitor voltage and first voltage, computing circuit output first reference
Signal, first reference signal are the difference of the first voltage and the first capacitor voltage.
5. the main switch leakage source voltage terminal of a kind of control method of switching circuit, sampling switch circuit obtains sampled signal, examine
It surveys inductive current and obtains current detection signal, it is characterised in that: the first reference signal is obtained according to the sampled signal, it is described to adopt
The peak value of sample signal and first reference signal are negatively correlated；When the current detection signal reaches first reference signal
When, the main switch shutdown of control switch circuit.
6. the control method of switching circuit according to claim 5, it is characterised in that: by the sampled signal and the first electricity
Pressure makees difference to control the turn-off time of main switch, the main switch of the difference and switching circuit of the sampled signal and first voltage
The turn-off time of pipe is positively correlated；The temperature of the main switch of sampling switch circuit is to obtain the first voltage, and described first
Voltage and the temperature are negatively correlated.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910758057.0A CN110504951A (en) | 2019-08-16 | 2019-08-16 | The control circuit and control method of switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910758057.0A CN110504951A (en) | 2019-08-16 | 2019-08-16 | The control circuit and control method of switching circuit |
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| CN110504951A true CN110504951A (en) | 2019-11-26 |
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| CN201910758057.0A Pending CN110504951A (en) | 2019-08-16 | 2019-08-16 | The control circuit and control method of switching circuit |
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| CN (1) | CN110504951A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111212504A (en) * | 2020-03-27 | 2020-05-29 | 杰华特微电子（杭州）有限公司 | BIFRED converter, control method thereof and LED drive circuit applying BIFRED converter |
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| US20130194845A1 (en) * | 2012-01-26 | 2013-08-01 | Stmicroelectronics S.R.L. | Control device of a switching power supply |
| KR20160004016A (en) * | 2014-07-02 | 2016-01-12 | 주식회사 실리콘웍스 | Signal control circuit and switching device comprising the same |
| CN105471270A (en) * | 2016-01-22 | 2016-04-06 | 矽力杰半导体技术(杭州)有限公司 | Control circuit and control method with self-adaptive blanking time |
| CN107426859A (en) * | 2016-10-26 | 2017-12-01 | 杰华特微电子（张家港）有限公司 | A kind of adaptive fast response circuit, fast response method and LED drive circuit |
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2019
- 2019-08-16 CN CN201910758057.0A patent/CN110504951A/en active Pending
Patent Citations (6)
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| US20130194845A1 (en) * | 2012-01-26 | 2013-08-01 | Stmicroelectronics S.R.L. | Control device of a switching power supply |
| KR20160004016A (en) * | 2014-07-02 | 2016-01-12 | 주식회사 실리콘웍스 | Signal control circuit and switching device comprising the same |
| CN105471270A (en) * | 2016-01-22 | 2016-04-06 | 矽力杰半导体技术(杭州)有限公司 | Control circuit and control method with self-adaptive blanking time |
| CN107426859A (en) * | 2016-10-26 | 2017-12-01 | 杰华特微电子（张家港）有限公司 | A kind of adaptive fast response circuit, fast response method and LED drive circuit |
| CN208656639U (en) * | 2018-04-19 | 2019-03-26 | 杭州士兰微电子股份有限公司 | Control circuit and switch converters for switch converters |
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Non-Patent Citations (1)
| Title |
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| 朱波;赵梦恋;杨朝;张书瑜;吴晓波;: "一种基于原边反馈控制的LED恒流驱动芯片", 微电子学, no. 02 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111212504A (en) * | 2020-03-27 | 2020-05-29 | 杰华特微电子（杭州）有限公司 | BIFRED converter, control method thereof and LED drive circuit applying BIFRED converter |
| CN111212504B (en) * | 2020-03-27 | 2023-10-27 | 杰华特微电子股份有限公司 | BIFRED converter, control method thereof and LED driving circuit applying BIFRED converter |
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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 Applicant after: Jiehuate Microelectronics Co.,Ltd. Address before: Room 424, building 1, 1500 Wenyi West Road, Cangqian street, Yuhang District, Hangzhou City, Zhejiang Province Applicant before: JOULWATT TECHNOLOGY Inc.,Ltd. |
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