CN1163925C - Current zero-crossing detection circuit of switching circuit - Google Patents
Current zero-crossing detection circuit of switching circuit Download PDFInfo
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- CN1163925C CN1163925C CNB001145495A CN00114549A CN1163925C CN 1163925 C CN1163925 C CN 1163925C CN B001145495 A CNB001145495 A CN B001145495A CN 00114549 A CN00114549 A CN 00114549A CN 1163925 C CN1163925 C CN 1163925C
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Abstract
The present invention relates to a current zero-crossing detection circuit device of switching circuits. In switching circuits, at least one of three points of a base unit except a middle point is connected with a voltage source which is relatively stable, and the points can be used as reference voltage sources. The present invention is characterized in that the circuit device is composed of a comparator or a logic gate circuit, and a plurality of voltage dividing resistors, wherein the voltage dividing resistors are connected with input ends of the comparator; the two input ends of the comparator are connected with one reference voltage source and both ends of the middle point by two sets of voltage dividing resistors, and one end of each voltage dividing resistor is grounded; an input end of the logical gating circuit is connected with the middle point by a set of voltage dividing resistors to measure voltage signals of electric current of the middle point, and one end of each voltage dividing resistor is grounded. When the voltage range of the middle point is compatible with the voltage range of the comparator or the logic circuit, the voltage dividing resistors can be omitted.
Description
Technical field:
The present invention relates to a kind of circuit that is used for switching circuit that includes the current over-zero testing circuit.
Technical background:
The current over-zero testing circuit of existing switching circuit has two kinds of methods: a kind of is the resistance detection method, both small resistors on the main circuit string, detect current zero-crossing point by measuring ohmically voltage drop, because resistance can cause loss in main circuit, therefore resistance value certainly will need very little, so just caused detection signal very weak, make that the anti-interference of control circuit is poor, in any case and resistance all can cause loss, in the application of low-voltage and high-current, this method is because loss is too big and impracticable.Simultaneously because this resistance must be external, make the integrated very difficult of this method.Another kind method is the current transformer detection method, both in main circuit, introduced the method for current transformer (or being similar to Hall device), convert current signal to voltage signal, again this voltage signal is handled (existing average, peak value, electric charge etc.) method, obtained the voltage signal that can be used for controlling.The shortcoming of the method be complicated, expensive, volume greatly, not easy of integration.In addition, more than a common drawback of two kinds of methods be to be insensitive for current zero-crossing point, because the voltage signal that above two kinds of methods obtain all is (being similar to the ratio characteristic) of the gradual change along with the variation of electric current, a strong signal can not be provided when current over-zero, cause them can not detect current zero-crossing point very accurately.
Summary of the invention:
The objective of the invention is to provide a kind of simple, sensitive, be easy to the integrated circuit that is used for switching circuit that includes the current over-zero testing circuit.
The present invention constitutes like this: comprise switching circuit, pulse-width modulation circuit, gate drive circuit, current over-zero testing circuit and power supply are formed, elementary cell in the switching circuit is except that mid point (C), its excess-three point (A, P, O) having any at least is to be connected with metastable voltage source, can be used as reference voltage source, it is characterized in that: the current over-zero testing circuit is made up of a comparator and several divider resistances of linking to each other with its input, two inputs of comparator are by two component piezoresistances of an end ground connection, be connected to the two ends of a reference voltage source and mid point (C), be used to measure the voltage signal of mid point (C) electric current, the output signal of comparator (Vk) is imported gate-drive logic control gate circuit with the output signal of pulse-width modulation circuit again, the output signal of gate-drive logic control gate circuit again by gate drive circuit with the closure of control switch circuit (S1) with cut-off.
Than the existing circuit that is used for switching circuit that comprises the current over-zero testing circuit, the invention has the advantages that and only adopt comparator, make it can be easy to integrate with " gate drive circuit ", also can integrate with " feedback control circuit ", owing to voltage jump is arranged at current over-zero, make this method can accurately detect current zero-crossing point very delicately, in addition, because the mid-point voltage saltus step occurs in after the reverse recovery of diode (or diode of switch body), therefore, this method can self adaptation be regulated the gate pole time-delay, reaches the purpose that makes diode reverse recovery loss minimum automatically.
Description of drawings:
Fig. 1 is the switching circuit reduced graph.
Fig. 2 is that switching circuit is simplified expander graphs.
Fig. 3 is the present invention detects current over-zero with comparator circuit circuit theory diagrams.
Fig. 4 is embodiments of the invention---be used for the schematic block circuit diagram of variable frequency control.
Embodiment:
As shown in Figure 3, elementary cell is except that mid point C in the switching circuit, its excess-three point A, P, O have at least any to be connected with metastable voltage source, can be used as the reference voltage source of comparison, two groups of several divider resistances that this current over-zero testing circuit device links to each other by a comparator and with its input are formed.Shown in the a---f among Fig. 3, two inputs of comparator are to form by two component piezoresistances of an end ground connection.Wherein one group of resistance is to receive mid point C, and other one group of resistance is to be benchmark with the voltage of O, P, A respectively, therefore six kinds of circuit forms are arranged, being used for the C point compares, adopt the method for electric resistance partial pressure that the voltage of main circuit is dropped to comparator acceptable scope, for the situation of main circuit voltage range in comparator scope compatibility, these divider resistances can save.
As shown in Figure 4, the circuit that is used for switching circuit that includes the current over-zero testing circuit, it comprises: comprise switching circuit, pulse-width modulation circuit, gate drive circuit, current over-zero testing circuit and power supply are formed, elementary cell in the switching circuit is except that mid point (C), its excess-three point (A, P, O) having any at least is to be connected with metastable voltage source, can be used as reference voltage source, it is characterized in that: the current over-zero testing circuit is made up of a comparator and several divider resistances of linking to each other with its input, two inputs of comparator are by two component piezoresistances of an end ground connection, be connected to the two ends of a reference voltage source and mid point (C), be used to measure the voltage signal of mid point (C) electric current, the output signal of comparator (Vk) is imported gate-drive logic control gate circuit with the output signal of pulse-width modulation circuit again, the output signal of gate-drive logic control gate circuit again by gate drive circuit with the closure of control switch circuit (S1) with cut-off.
When the switch connection in the switching circuit, inductance is recharged the generation forward current.Behind the certain hour, be subjected to outside control, switch disconnects.At this time, owing to have forward current in the inductance, make diode forward conducting afterflow, inductance bears counter voltage simultaneously, and its electric current reduces gradually, and when inductive current was reduced to zero, diode turn-offed naturally, and at this time the mid point C in the circuit can produce jump in potential.Convert this jump in potential to digital signal by comparator circuit, both can be used for having detected the zero crossing in the inductance.The voltage of mid point C in the circuit is often owing to the action of switch produces noise, and for avoiding the influence of noise to circuit, this signal need be for further processing, and just can be used as the control signal of switch.The output VK of the comparator in the current over-zero testing circuit receives on the gate drive circuit by trigger with pulse-width signal Vb, with the closure and the disconnection of control switch contactor (S1), switching signal is carried out interlocking to reach elimination noise, jamproof purpose by trigger like this.
Claims (1)
1, a kind of circuit that is used for switching circuit that includes the current over-zero testing circuit, comprise switching circuit, pulse-width modulation circuit, gate drive circuit, current over-zero testing circuit and power supply are formed, elementary cell in the switching circuit is except that mid point (C), its excess-three point (A, P, O) having any at least is to be connected with metastable voltage source, can be used as reference voltage source, it is characterized in that: the current over-zero testing circuit is made up of a comparator and several divider resistances of linking to each other with its input, two inputs of comparator are by two component piezoresistances of an end ground connection, be connected to the two ends of a reference voltage source and mid point (C), be used to measure the voltage signal of mid point (C) electric current, the output signal of comparator (Vk) is imported gate-drive logic control gate circuit with the output signal of pulse-width modulation circuit again, the output signal of gate-drive logic control gate circuit again by gate drive circuit with the closure of control switch circuit (S1) with cut-off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001145495A CN1163925C (en) | 2000-04-30 | 2000-04-30 | Current zero-crossing detection circuit of switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001145495A CN1163925C (en) | 2000-04-30 | 2000-04-30 | Current zero-crossing detection circuit of switching circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1321995A CN1321995A (en) | 2001-11-14 |
| CN1163925C true CN1163925C (en) | 2004-08-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001145495A Expired - Fee Related CN1163925C (en) | 2000-04-30 | 2000-04-30 | Current zero-crossing detection circuit of switching circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1163925C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9404948B2 (en) * | 2012-12-21 | 2016-08-02 | Microchip Technology Incorporated | Mains voltage zero-crossing detector |
| CN104092388A (en) * | 2014-06-17 | 2014-10-08 | 昆山弗尔赛能源有限公司 | Synchronous rectifying BOOST circuit with reverse current prevention |
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2000
- 2000-04-30 CN CNB001145495A patent/CN1163925C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CN1321995A (en) | 2001-11-14 |
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Owner name: JOULWATT MICROELECTRONICS (SUZHOU) CO., LTD. Free format text: FORMER OWNER: HUANG BIWU Effective date: 20140520 |
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Free format text: CORRECT: ADDRESS; FROM: 350009 FUZHOU, FUJIAN PROVINCE TO: 311121 HANGZHOU, ZHEJIANG PROVINCE |
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Effective date of registration: 20140520 Address after: Hangzhou City, Zhejiang province Yuhang District 311121 West Street warehouse before No. 1500 Building 1 room 424 Patentee after: Jevat Microelectronics (Hangzhou) Co., Ltd. Address before: 350009 Fujian city of Fuzhou province Shuangfeng quanta road building 9G easy computer Monitor Company Patentee before: Huang Biwu |
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