CN214101207U - Control circuit of switch circuit and switch circuit - Google Patents
Control circuit of switch circuit and switch circuit Download PDFInfo
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- CN214101207U CN214101207U CN202023215847.1U CN202023215847U CN214101207U CN 214101207 U CN214101207 U CN 214101207U CN 202023215847 U CN202023215847 U CN 202023215847U CN 214101207 U CN214101207 U CN 214101207U
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- 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
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
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Abstract
The utility model discloses a switch circuit's control circuit, including output capacitance, control circuit includes: the output voltage change detection circuit receives a sampling signal representing the output voltage of the switch circuit and outputs a voltage change representation signal representing the output voltage change of the switch circuit; and the current adjusting circuit adjusts the charging current of the output capacitor according to the voltage change characterization signal, so that the charging current is increased when the switching circuit is started, and the charging current is reduced when the switching circuit is started. The utility model has the advantages of the system start-up speed is fast, and the time of overshooting is little.
Description
Technical Field
The utility model relates to a switching circuit technical field especially relates to a switching circuit's control circuit and switching circuit.
Background
A functional block diagram of a conventional LED driving circuit is shown in fig. 1, wherein an external ac input voltage is rectified by a rectifier bridge to obtain a pulsating dc voltage, the dc voltage is converted by a switching circuit to generate an output voltage for supplying to a load, and a control circuit receives the dc voltage, the output voltage V0 and a sampling signal output by the switching circuit to generate a control signal for controlling a switching state in the switching circuit, so that the switching circuit outputs an expected output current signal. An output capacitor C02 is arranged at the output end of the switch circuit, when the power supply is started, the system charges an output filter capacitor C02, and when the voltage of the capacitor reaches the voltage of a load, the system starts to supply power to the load. In a dimming system, when the system is started at a low current, the time required for charging the voltage of an output capacitor to the voltage of a load is long, so that the starting time of the system is too long, and the starting speed of the system is influenced.
In the prior art, when a system is started at a low current, a reference voltage is increased by setting a certain time threshold (or within a certain output voltage threshold), and a charging current of an output capacitor is increased to achieve quick start of the system. The time setting of the technical scheme depends on parameters such as output voltage, current and capacitance, so that the time setting is not flexible enough, if the time setting is too long, the starting is obviously overshot, and if the time setting is too short, the voltage of the output capacitor cannot be charged to a steady-state value in time, so that the system driving time is still very long. The setting of the output voltage threshold value depends on the output voltage of the system, so that the setting is not flexible enough, and the application range of the system is influenced; if the voltage threshold is set to be too small, the system starting time is too long, and if the voltage threshold is set to be too large, overshoot is caused, and even the fast starting mode cannot be exited.
Disclosure of Invention
In view of this, an object of the present invention is to provide a control circuit of a switch circuit and a switch circuit, which charge an output capacitor with a larger reference current when a system is started, and control the conversion from a fast start state to a normal operation state by detecting the change of an output voltage in the switch circuit.
In order to achieve the above object, the present invention provides a control circuit of a switch circuit, including an output capacitor, the control circuit includes:
the output voltage change detection circuit receives a sampling signal representing the output voltage of the switch circuit and outputs a voltage change representation signal representing the output voltage change of the switch circuit;
and the current adjusting circuit adjusts the charging current of the output capacitor according to the voltage change characterization signal, so that the charging current is increased when the switching circuit is started, and the charging current is reduced when the switching circuit is started.
Preferably, the current adjustment circuit includes:
the comparison circuit compares the received voltage change characterization signal with a reference voltage threshold value and outputs a control signal;
and the voltage adjusting circuit adjusts the charging current of a compensation capacitor according to the control signal to obtain voltage adjusting signals at two ends of the compensation capacitor, and adjusts the charging current of the output capacitor according to the voltage adjusting signals.
Preferably, the output voltage change detection circuit includes a voltage change rate detection circuit, and the voltage change characterizing signal is a first voltage signal characterizing a rate of change of the output voltage of the switching circuit.
Preferably, the voltage change rate detection circuit includes an RC differential circuit, the RC differential circuit includes a first resistor and a first capacitor, the first resistor and the first capacitor are connected in series, one end of the first resistor is grounded, the other end of the first resistor is connected to the first input end of the comparison circuit, and the other end of the first capacitor is connected to the positive electrode of the output voltage of the switching circuit.
Preferably, the comparison circuit includes a comparator, and the comparator inputs the first voltage signal and the reference voltage threshold, compares the first voltage signal and the reference voltage threshold, and outputs the control signal.
Preferably, the voltage adjustment circuit includes:
a large current unit outputting a large reference current;
a reference current unit generating a reference steady-state current, the large reference current being greater than the reference steady-state current;
a switch connected to the comparison circuit and the large current unit, respectively, wherein,
when the first voltage signal is greater than or equal to the reference voltage threshold, the control signal controls the switch to be closed, and the large reference current and the reference steady-state current jointly charge the compensation capacitor;
when the first voltage signal is smaller than the reference voltage threshold value, the control signal controls the switch to be switched off, and the compensation capacitor is charged by the reference steady-state current.
Preferably, the control circuit further includes:
and the switching signal generating circuit receives the voltage adjusting signal at two ends of the compensation capacitor and the inductive current sampling signal in the switching circuit, and generates a switching signal to control a main power tube in the switching circuit according to the comparison between the voltage adjusting signal and the inductive current sampling signal so as to adjust the magnitude of the charging current.
Preferably, the output voltage change detection circuit includes a voltage change amount detection circuit, and the voltage change characterization signal is a second voltage signal characterizing the output voltage change amount of the switch circuit;
the voltage variation detection circuit is used for receiving a sampling signal representing the output voltage of the switch circuit in a preset period and outputting the second voltage signal.
In order to achieve the above object, the present invention provides a switching circuit, which comprises a power stage circuit and a control circuit of the switching circuit,
and the control circuit of the switching circuit receives the voltage output by the rectifier bridge and the voltage signal output by the switching circuit to generate a switching control signal to control the switching action of a power switching tube in the power stage circuit.
Preferably, the switch circuit is an LED driving circuit.
Compared with the prior art, the utility model provides a switch circuit's control circuit and switch circuit, the beneficial effect who brings is: when the system is started, the output capacitor is charged by a large reference current, and the conversion from a quick starting state to a normal working state is controlled by detecting the change of the output voltage in the switch circuit; the output voltage of the switch circuit can be self-adapted, the quick start of the switch circuit is realized, when the output voltage does not reach a stable state, the output capacitor is charged by the large reference current, the output voltage quickly rises at a large change rate, and the quick start mode can be quitted when the system is close to the stable state.
Drawings
Fig. 1 is a schematic block diagram of a conventional LED driving circuit.
Fig. 2 is a functional block diagram of a control circuit of a switching circuit according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail with reference to the specific embodiments shown in the drawings, but the embodiments are not limited to the present invention, and structural, methodological, or functional changes made by those skilled in the art according to the embodiments are included in the scope of the present invention.
As shown in fig. 2, in an embodiment of the present invention, the present invention provides a control circuit of a switching circuit, including an output capacitor, the control circuit includes:
an output voltage change detection circuit 20 for receiving a sampling signal representing the output voltage of the switching circuit and outputting a voltage change representation signal representing the change of the output voltage of the switching circuit;
and the current adjusting circuit 21 adjusts the charging current of the output capacitor according to the voltage change characterization signal, so that the charging current is increased when the switching circuit is started, and the charging current is decreased when the switching circuit is started.
The utility model discloses an embodiment realizes the detection that switch circuit's output voltage changed through detecting the output voltage rate of change. The output voltage change detection circuit comprises a voltage change rate detection circuit, and the voltage change characterization signal is a first voltage signal which characterizes the output voltage change rate of the switch circuit. Specifically, the voltage change rate detection circuit comprises an RC differential circuit, the RC differential circuit comprises a first resistor R and a first capacitor C1, the first resistor R and the first capacitor C1 are connected in series, one end of the first resistor R is grounded, the other end of the first resistor R is connected with a first input end of the comparison circuit, and the other end of the first capacitor C1 is connected with an output voltage anode of the switch circuit. The RC differential circuit is used for collecting the output voltage of the switch circuit and outputting a voltage signal of the change rate of the output voltage of the switch circuit to the comparison circuit, so that the detection of the change rate of the output voltage of the switch circuit is realized.
The utility model discloses also can realize the detection that switch circuit's output voltage changes through the change volume that detects output voltage. The output voltage change detection circuit comprises a voltage change amount detection circuit, and the voltage change characterization signal is a second voltage signal for characterizing the output voltage change amount of the switch circuit. The voltage variation detection circuit receives a sampling signal representing the output voltage of the switch circuit in a preset period and outputs the second voltage signal.
In an embodiment of the present invention, the current adjusting circuit 21 includes a comparing circuit 210 and a voltage adjusting circuit 211. The comparison circuit 210 compares the received voltage variation characterization signal with a reference voltage threshold and outputs a control signal. The voltage adjusting circuit 211 adjusts a charging current to a compensation capacitor C according to the control signal, obtains a voltage adjusting signal at two ends of the compensation capacitor C, and adjusts the charging current of the output capacitor according to the voltage adjusting signal. Specifically, the comparison circuit includes a comparator U1, the comparator U1 inputs the first voltage signal and the reference voltage threshold, compares the first voltage signal and the reference voltage threshold, and outputs the control signal. When the first voltage signal is greater than or equal to the reference voltage threshold K, outputting a control signal for adjusting the increase of the charging current, and when the first voltage signal is less than the reference voltage threshold, outputting a control signal for adjusting the decrease of the charging current. For example, the reference voltage threshold K is set to 200-300V/S.
Specifically, the voltage adjusting circuit 211 includes a large current unit 2110, a reference current unit 2111 and a switch S. The large current unit outputs a large reference current. The reference current unit generates a reference steady-state current, and the large reference current is larger than the reference steady-state current. For example, the large reference current is set to be 2-100 times of the reference steady-state current. The switch is respectively connected with the comparison circuit and the large-current unit. When the first voltage signal is larger than or equal to the reference voltage threshold value, the control signal controls the switch to be closed, and large reference current I flowing through the switchQSAnd a reference steady-state current IREFForming a charging current, the large reference current IQSWith said reference steady-state current IREFCharging the compensation capacitors together; when the first voltage signal is smaller than the reference voltage threshold value, the control signal controls the switch to be switched off, and the reference steady-state current IREFAnd charging the compensation capacitor.
An embodiment of the utility model, control circuit still includes switching signal production circuit 22, receives the voltage adjustment signal V at compensation electric capacity both endscAnd an inductor current sampling signal V in the switching circuitfAccording to said voltage regulation signal VcAnd said inductor current sampling signal VfGenerating a switching signal to control a main power tube in the switching circuit so as to adjust the magnitude of the charging current. When the large reference current and the reference steady-state current charge the compensation capacitor together, the voltage at two ends of the compensation capacitor rises rapidly, the voltage adjusting signals at two ends of the compensation capacitor are larger than the inductive current sampling signal in the switch circuit, the conduction time of the main power tube in the switch circuit is prolonged, the charging current of the output capacitor in the switch circuit is increased, and the output is realizedAnd the capacitor is charged quickly, and the system enters a quick start mode. When the compensation capacitor is charged by the reference steady-state current, the voltage at the two ends of the compensation capacitor slowly rises, the voltage adjusting signals at the two ends of the compensation capacitor are smaller than the inductive current sampling signal in the switch circuit, the conduction time of the main power tube in the switch circuit is reduced, the charging current of the output capacitor in the switch circuit is reduced, the output voltage of the switch circuit is in a steady state, the system exits a quick start stage, and the system is in a steady state.
The utility model provides a switch circuit, including power stage circuit with switch circuit's control circuit, switch circuit's control circuit receives the voltage of rectifier bridge output and the voltage signal of switch circuit output to produce on-off control signal control the switch action of power switch tube in the power stage circuit. The switch circuit is an LED drive circuit.
The above switching circuit is an LED driving circuit as an example, but the control circuit of the switching circuit of the present invention can also be used in suitable switching circuits such as an ac-dc voltage conversion circuit and a dc-dc voltage conversion circuit.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
Claims (10)
1. A control circuit for a switching circuit, comprising an output capacitor, the control circuit comprising:
the output voltage change detection circuit receives a sampling signal representing the output voltage of the switch circuit and outputs a voltage change representation signal representing the output voltage change of the switch circuit;
and the current adjusting circuit adjusts the charging current of the output capacitor according to the voltage change characterization signal, so that the charging current is increased when the switching circuit is started, and the charging current is reduced when the switching circuit is started.
2. The control circuit of the switching circuit of claim 1, wherein the current regulation circuit comprises:
the comparison circuit compares the received voltage change characterization signal with a reference voltage threshold value and outputs a control signal;
and the voltage adjusting circuit adjusts the charging current of a compensation capacitor according to the control signal to obtain voltage adjusting signals at two ends of the compensation capacitor, and adjusts the charging current of the output capacitor according to the voltage adjusting signals.
3. The control circuit of the switching circuit according to claim 2,
the output voltage change detection circuit comprises a voltage change rate detection circuit, and the voltage change characterization signal is a first voltage signal which characterizes the output voltage change rate of the switch circuit.
4. The control circuit of the switching circuit according to claim 3,
the voltage change rate detection circuit comprises an RC differential circuit, the RC differential circuit comprises a first resistor and a first capacitor, the first resistor and the first capacitor are connected in series, one end of the first resistor is grounded, the other end of the first resistor is connected with a first input end of the comparison circuit, and the other end of the first capacitor is connected with the output voltage anode of the switch circuit.
5. The control circuit of the switching circuit according to claim 3,
the comparison circuit comprises a comparator, wherein the comparator inputs the first voltage signal and the reference voltage threshold, compares the first voltage signal and the reference voltage threshold and outputs the control signal.
6. The control circuit of the switching circuit of claim 5, wherein the voltage regulation circuit comprises:
a large current unit outputting a large reference current;
a reference current unit generating a reference steady-state current, the large reference current being greater than the reference steady-state current;
the switch is respectively connected with the comparison circuit and the large-current unit, when the first voltage signal is greater than or equal to the reference voltage threshold value, the control signal controls the switch to be closed, and the large reference current and the reference steady-state current jointly charge the compensation capacitor; when the first voltage signal is smaller than the reference voltage threshold value, the control signal controls the switch to be switched off, and the compensation capacitor is charged by the reference steady-state current.
7. The control circuit of the switching circuit according to claim 2, wherein the control circuit further comprises:
and the switching signal generating circuit receives the voltage adjusting signal at two ends of the compensation capacitor and the inductive current sampling signal in the switching circuit, and generates a switching signal to control a main power tube in the switching circuit according to the comparison between the voltage adjusting signal and the inductive current sampling signal so as to adjust the magnitude of the charging current.
8. The control circuit of the switching circuit according to claim 1,
the output voltage change detection circuit comprises a voltage change detection circuit, and the voltage change characterization signal is a second voltage signal for characterizing the output voltage change of the switch circuit;
the voltage variation detection circuit is used for receiving a sampling signal representing the output voltage of the switch circuit in a preset period and outputting the second voltage signal.
9. A switching circuit comprising a power stage circuit and a control circuit for the switching circuit of any one of claims 1-8;
and the control circuit of the switching circuit receives the voltage output by the rectifier bridge and the voltage signal output by the switching circuit to generate a switching control signal to control the switching action of a power switching tube in the power stage circuit.
10. The switching circuit according to claim 9, wherein the switching circuit is an LED driving circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023215847.1U CN214101207U (en) | 2020-12-28 | 2020-12-28 | Control circuit of switch circuit and switch circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202023215847.1U CN214101207U (en) | 2020-12-28 | 2020-12-28 | Control circuit of switch circuit and switch circuit |
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| CN214101207U true CN214101207U (en) | 2021-08-31 |
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| CN202023215847.1U Active CN214101207U (en) | 2020-12-28 | 2020-12-28 | Control circuit of switch circuit and switch circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114364091A (en) * | 2021-12-21 | 2022-04-15 | 杭州士兰微电子股份有限公司 | LED drive control circuit, LED drive control method and LED drive system |
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2020
- 2020-12-28 CN CN202023215847.1U patent/CN214101207U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114364091A (en) * | 2021-12-21 | 2022-04-15 | 杭州士兰微电子股份有限公司 | LED drive control circuit, LED drive control method and LED drive system |
| CN114364091B (en) * | 2021-12-21 | 2023-06-20 | 杭州士兰微电子股份有限公司 | LED drive control circuit, LED drive control method and LED drive system |
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