CN112260534A - Control circuit and control method of switching circuit and switching power supply circuit - Google Patents

Control circuit and control method of switching circuit and switching power supply circuit Download PDF

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Publication number
CN112260534A
CN112260534A CN202011144260.8A CN202011144260A CN112260534A CN 112260534 A CN112260534 A CN 112260534A CN 202011144260 A CN202011144260 A CN 202011144260A CN 112260534 A CN112260534 A CN 112260534A
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CN
China
Prior art keywords
voltage
circuit
control
switching
threshold
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Pending
Application number
CN202011144260.8A
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Chinese (zh)
Inventor
黄必亮
毛卫军
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Joulwatt Technology Hangzhou Co Ltd
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Joulwatt Technology Hangzhou Co Ltd
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Priority to CN202011144260.8A priority Critical patent/CN112260534A/en
Publication of CN112260534A publication Critical patent/CN112260534A/en
Pending legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention provides a control circuit and a control method of a switching circuit and a switching power supply circuit, which amplify errors of feedback voltage and reference voltage representing output voltage to obtain compensation voltage; when the compensation voltage is larger than a first threshold value, clamping the compensation voltage at the first threshold value, and turning off a main power tube of the compensation voltage control switch circuit; the first threshold is set according to the topology of the switching circuit, the input voltage and the output voltage. The invention can avoid overlarge inductive current, ensure sufficient output and reduce the overcharge voltage during short circuit recovery.

Description

Control circuit and control method of switching circuit and switching power supply circuit
Technical Field
The present invention relates to the field of power electronics, and in particular, to a switching circuit control circuit, a switching circuit control method, and a switching power supply circuit.
Background
Among various control modes of the switching conversion circuit, Constant On Time (COT) control is widely adopted due to the advantages of high transient response speed, simple structure and the like. And carrying out error amplification on the feedback voltage representing the output voltage of the switching circuit and the reference voltage to obtain the compensation voltage. In constant on-time control, the compensation voltage controls the on-time. In the conventional scheme, the on-time rises with the rise of the compensation voltage. However, the compensation voltage is too large, so that the inductive current is too large, and the power tube is damaged; too small a compensation voltage may cause too large a deviation of the output from the expected value and insufficient output. Therefore, the magnitude of the compensation voltage needs to be considered in the control of the switching circuit.
Disclosure of Invention
The invention aims to provide a control circuit and a control method of a switching circuit with a simple circuit and a switching power supply circuit, which are used for solving the problems of overlarge inductive current and insufficient output in the prior art.
To achieve the above object, the present invention provides a control circuit of a switching circuit, comprising
The first operational amplifier is used for carrying out error amplification on the feedback voltage representing the output voltage and the reference voltage to obtain compensation voltage;
a first control circuit that clamps the compensation voltage at a first threshold when the compensation voltage is greater than the first threshold; when the compensation voltage is less than or equal to a first threshold value, the first control circuit outputs the compensation voltage; controlling the main power tube of the switch circuit to be switched off according to the compensation voltage;
a first threshold generation circuit that sets the first threshold according to a topology of the switching circuit, the input voltage, and the output voltage.
Optionally, the first threshold is set according to a topology structure of the switch circuit, the representation signal of the input voltage, and the representation signal of the output voltage.
Optionally, when the switching circuit is a voltage-reducing circuit, the first threshold is proportional to a ratio of the output voltage to the input voltage.
Optionally, when the switch circuit is a voltage boost circuit, the first threshold is proportional to a difference between the output voltage and the input voltage, and inversely proportional to the output voltage.
Optionally, when the switching circuit is a buck-boost circuit, the first threshold is directly proportional to the output voltage and inversely proportional to the sum of the input voltage and the output voltage.
Optionally, when the switching circuit is a flyback circuit, the first threshold is in negative correlation with a ratio of the input voltage to the output voltage, and is in positive correlation with a turn ratio of a primary side to a secondary side of the flyback circuit.
Optionally, the first control circuit includes a first adjusting tube, a second adjusting tube, a current source and a second operational amplifier, a first end of the first adjusting tube is connected to the high potential end, a second end of the first adjusting tube is connected to the current source, and a control end of the first adjusting tube is connected to an output end of the first operational amplifier; the first input end of the second operational amplifier is connected with the second end of the first adjusting tube, the second input end of the second operational amplifier receives a first threshold value, the output end of the second operational amplifier is connected with the control end of the second adjusting tube, the first end of the second adjusting tube is connected with the control end of the first adjusting tube, and the second end of the second adjusting tube is grounded; the second end voltage of the first adjusting tube is used for representing the compensation voltage.
The invention also provides a control method of the switch circuit, which amplifies the error of the feedback voltage representing the output voltage and the reference voltage to obtain the compensation voltage; when the compensation voltage is larger than a first threshold value, clamping the compensation voltage at the first threshold value, and turning off a main power tube of the compensation voltage control switch circuit; the first threshold is set according to the topology of the switching circuit, the input voltage and the output voltage.
The invention also provides a switching power supply circuit which comprises any one of the control circuits.
Compared with the prior art, the invention has the following advantages: amplifying errors of the feedback voltage representing the output voltage and the reference voltage to obtain a compensation voltage; when the compensation voltage is larger than a first threshold value, clamping the compensation voltage at the first threshold value, and turning off a main power tube of the compensation voltage control switch circuit; the first threshold is set according to the topology of the switching circuit, the input voltage and the output voltage. The invention can avoid the phenomenon that the power tube is damaged due to overlarge inductive current, can also ensure that the output voltage has enough output, and can reduce the overcharge voltage during short circuit recovery.
Drawings
FIG. 1 is a schematic diagram of a control circuit of the switching circuit of the present invention;
FIG. 2 is a schematic diagram of a first control circuit of the switching circuit of the present invention;
FIG. 3 is a waveform diagram of the switching circuit of the present invention;
Detailed Description
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 invention is intended to cover alternatives, modifications, equivalents and alternatives which may be included within the spirit and scope of the 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 in simplified form and are not to precise scale for the purpose of facilitating and clearly explaining the embodiments of the present invention.
As shown in fig. 1, a schematic diagram of a control circuit of a switching circuit of the present invention is illustrated, wherein the switching circuit includes a main power transistor and a synchronous rectifier, such as a buck circuit, a boost circuit, a flybuck circuit, etc. The control circuit comprises a first operational amplifier U01, a clamping circuit U02 and a clamping value generating circuit U03, wherein the first operational amplifier U01 carries out error amplification on a feedback voltage FB representing the output voltage of the switching circuit and a reference voltage VREF, the input end of the clamping circuit U02 is connected with the output end of the first operational amplifier U01 to output a compensation voltage VCOMP, and when the compensation voltage VCOMP is larger than a first threshold value clamp, the clamping circuit U02 clamps the compensation voltage VCOMP at the first threshold value clamp. The first threshold value clamp is obtained according to different switch circuit topologies, the output voltage VOUT and the input voltage VIN of the switch circuit. The compensation voltage COMP controls the conduction time of the main power tube of the switching circuit, the larger the compensation voltage COMP is, the larger the conduction time is, the larger the duty ratio is, and therefore according to the relation between the duty ratio and the input and output of the switching circuit, the clamping value of the compensation voltage, namely the first threshold value clamp, can be set according to the input and output of the switching circuit. When the switching circuit is a step-down circuit, the first threshold value clamp is set in proportion to the ratio of the input voltage to the input voltage. When the switching circuit is a boost circuit, the first threshold value clamp is set in proportion to the output voltage and in inverse proportion to the sum of the input voltage and the output voltage. When the switching circuit is a buck-boost circuit, the first threshold clamp is set in direct proportion to the output voltage and in inverse proportion to the sum of the input voltage and the output voltage. When the switching circuit is a flyback circuit, the first threshold value clamp is set to be in positive correlation with the ratio of the input voltage to the output voltage, and the first threshold value clamp is set to be in positive correlation with the turn ratio of the primary side to the secondary side of the flyback circuit. The input voltage and the output voltage of the switching circuit are obtained by sampling, and signals representing the input voltage and the output voltage can also be obtained by filtering or sampling and holding signals of a switching node of the switching circuit. For example, the voltage reduction circuit may filter the voltage at the connection end of the main power transistor and the synchronous rectifier transistor to obtain a signal representing the output voltage, or sample and hold the voltage at the connection end when the main power transistor is turned on to obtain a signal representing the input voltage.
Fig. 2 illustrates a schematic diagram of a first control circuit of the present invention, the first control circuit includes a first adjusting transistor M1, a second adjusting transistor M2, a current source I1 and a second operational amplifier U201, a first end of the first adjusting transistor M1 is connected to a high potential end, a second end of the first adjusting transistor M1 is connected to a current source I1, and a control end of the first adjusting transistor M1 is connected to a control end of the first operational amplifier U01; the first end of the second adjusting tube M2 is connected with the control end of the first adjusting tube M1, and the second end of the second adjusting tube M2 is grounded; the first end of the second operational amplifier U02 is connected with the second end of the second adjusting tube M2, the second end of the second operational amplifier U201 receives a first threshold value clamp, the output end of the second operational amplifier U201 is connected with the control end of the second adjusting tube M2, and the voltage of the second end of the first operational amplifier U201 is a compensation voltage COMP.
Fig. 3 is a waveform diagram of a switching circuit according to the present invention, which is exemplified by a step-down circuit and is described with reference to the circuit shown in fig. 1. In the figure, ramp is a ramp signal, COMP is a compensation voltage, when the ramp signal ramp rises to the compensation voltage COMP, the main power tube is turned off, and when the compensation voltage COMP rises to a first threshold value clamp, the compensation voltage COMP is clamped at clamp; when the clock signal clk is detected, the main power tube is turned on.
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 (9)

1. A control circuit for a switching circuit, characterized by: the method comprises the following steps:
the first operational amplifier is used for carrying out error amplification on the feedback voltage representing the output voltage and the reference voltage to obtain compensation voltage;
the first control circuit clamps the compensation voltage at a first threshold value for output when the compensation voltage is greater than the first threshold value; when the compensation voltage is less than or equal to a first threshold value, the first control circuit outputs the compensation voltage; controlling the main power tube of the switch circuit to be switched off according to the compensation voltage;
a first threshold generation circuit that sets the first threshold according to a topology of the switching circuit, the input voltage, and the output voltage.
2. The control circuit of the switching circuit according to claim 1, characterized in that: according to filtering or sampling and holding of a switch node signal of a switch circuit, a representation signal of input voltage and a representation signal of output voltage are obtained; and setting the first threshold according to the topological structure of the switch circuit, the representation signal of the input voltage and the representation limit number of the output voltage.
3. The control circuit of the switching circuit according to claim 1, characterized in that: when the switch circuit is a voltage reduction circuit, the first threshold is in direct proportion to the ratio of the output voltage to the input voltage.
4. The control circuit of the switching circuit according to claim 1, characterized in that: when the switch circuit is a booster circuit, the first threshold is proportional to the difference between the output voltage and the input voltage and inversely proportional to the output voltage.
5. The control circuit of the switching circuit according to claim 1, characterized in that: when the switch circuit is a buck-boost circuit, the first threshold is proportional to the output voltage and inversely proportional to the sum of the input voltage and the output voltage.
6. The control circuit of the switching circuit according to claim 1, characterized in that: when the switching circuit is a flyback circuit, the first threshold value is in negative correlation with the ratio of the input voltage to the output voltage, and is in positive correlation with the turn ratio of the primary side to the secondary side of the flyback circuit.
7. The control circuit of the switching circuit according to claim 6, characterized in that: the first control circuit comprises a first adjusting tube, a second adjusting tube, a current source and a second operational amplifier, wherein the first end of the first adjusting tube is connected with a high potential end, the second end of the first adjusting tube is connected with the current source, and the control end of the first adjusting tube is connected with the output end of the first operational amplifier; the first input end of the second operational amplifier is connected with the second end of the first adjusting tube, the second input end of the second operational amplifier receives a first threshold value, the output end of the second operational amplifier is connected with the control end of the second adjusting tube, the first end of the second adjusting tube is connected with the control end of the first adjusting tube, and the second end of the second adjusting tube is grounded; the second end voltage of the first adjusting tube is used for representing the compensation voltage.
8. A control method of a switching circuit is characterized in that: amplifying errors of the feedback voltage representing the output voltage and the reference voltage to obtain a compensation voltage; when the compensation voltage is larger than a first threshold value, clamping the compensation voltage at the first threshold value, and turning off a main power tube of the compensation voltage control switch circuit; the first threshold is set according to the topology of the switching circuit, the input voltage and the output voltage.
9. A switching power supply circuit characterized by: comprising a control circuit as claimed in any one of claims 1 to 7.
CN202011144260.8A 2020-10-23 2020-10-23 Control circuit and control method of switching circuit and switching power supply circuit Pending CN112260534A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011144260.8A CN112260534A (en) 2020-10-23 2020-10-23 Control circuit and control method of switching circuit and switching power supply circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011144260.8A CN112260534A (en) 2020-10-23 2020-10-23 Control circuit and control method of switching circuit and switching power supply circuit

Publications (1)

Publication Number Publication Date
CN112260534A true CN112260534A (en) 2021-01-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011144260.8A Pending CN112260534A (en) 2020-10-23 2020-10-23 Control circuit and control method of switching circuit and switching power supply circuit

Country Status (1)

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CN (1) CN112260534A (en)

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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 901-23, 9 / F, west 4 building, Xigang development center, 298 Zhenhua Road, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province, 310030

Applicant before: JOULWATT TECHNOLOGY Inc.,Ltd.

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