CN203911793U - Zero-cross detection circuit applied to switch power supply synchronous rectification converter - Google Patents
Zero-cross detection circuit applied to switch power supply synchronous rectification converter Download PDFInfo
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- CN203911793U CN203911793U CN201420324787.2U CN201420324787U CN203911793U CN 203911793 U CN203911793 U CN 203911793U CN 201420324787 U CN201420324787 U CN 201420324787U CN 203911793 U CN203911793 U CN 203911793U
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Abstract
The utility model provides a zero-cross detection circuit applied to a switch power supply synchronous rectification converter. The circuit comprises a working state control circuit, a detection signal conversion circuit and a detection signal comparison circuit. The working state control circuit receives a main switch MOS tube drive signal Vd and outputs a control signal Vcol to the detection signal conversion circuit. The detection signal conversion circuit receives a zero-cross detection point signal Vz and outputs a comparison signal Icop to the detection signal comparison circuit. Zero-cross of the detection point signal is judged by the detection signal comparison circuit, and a signal Vout is outputted to control connection and disconnection of a synchronous MOS tube. When the converter works in a discontinuous inductive current mode, the zero-cross state of inductive current is automatically detected by the zero-cross detection circuit, and the synchronous MOS tube is timely disconnected so that generation of a current backward flow phenomenon is prevented. With design of the structure of the zero-cross detection circuit, change of environment temperature and a manufacturing technology angle has extremely low influence on the output signal of the zero-cross detection circuit.
Description
Technical field
The utility model relates to the design of Switching Power Supply synchronous rectifier converter, in particular, and a kind of synchronous rectifier converter current over-zero testing circuit.
Background technology
In the design process of converter, if asynchronous structure need to adopt diode to realize afterflow.Asynchronous converter using fly-wheel diode is conducive to the output of high voltage, and production cost is also lower simultaneously.But fly-wheel diode can produce more power consumption when electric current is larger, be unfavorable for the lifting of transducer effciency.Synchronous rectifier converter adopts power MOS pipe to replace fly-wheel diode, and requires the grid voltage and the Phase synchronization that is rectified voltage of power MOS pipe, and this power MOS pipe is called as synchronous metal-oxide-semiconductor.Because the on state resistance of synchronous metal-oxide-semiconductor is very low, so the efficiency of synchronous rectifier converter is very high.But, when synchronous rectifier converter works in discontinous mode, if can not turn-off in time synchronous metal-oxide-semiconductor when inductive current is zero, there will be electric current to pour in down a chimney phenomenon.Electric current pours in down a chimney and can cause the increase of converter power consumption and damage element.Therefore, in synchronous rectifier converter design stability accurately current over-zero testing circuit there is important effect.
Utility model content
Technical problem to be solved in the utility model has been to provide a kind of zero cross detection circuit that is applied to Switching Power Supply synchronous rectifier converter.
The technical solution of the utility model is as follows: be applied to the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it comprises working state controlling circuit, detection signal change-over circuit and detection signal comparison circuit.Working state controlling circuit receives main switch metal-oxide-semiconductor and drives signal, and output services state control signal is in detection signal change-over circuit.Detection signal change-over circuit receives zero passage detection point signal, and exports comparison signal in detection signal comparison circuit.Detection signal outputs to the grid of synchronous metal-oxide-semiconductor using comparative result as control signal.
Be applied in the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, working state controlling circuit comprises main switch metal-oxide-semiconductor driving signal input, inverter, No. 1 metal-oxide-semiconductor and No. 2 metal-oxide-semiconductors.Wherein main switch metal-oxide-semiconductor driving signal input connects the input of inverter, and connects the grid of No. 2 metal-oxide-semiconductors.The output of inverter connects the grid of No. 1 metal-oxide-semiconductor, and the drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 2 metal-oxide-semiconductors.The source ground of No. 2 metal-oxide-semiconductors.
Be applied in the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, detection signal change-over circuit comprises zero passage detection point signal input part, 1 to No. 7 metal-oxide-semiconductor.Wherein zero passage detection point signal input part is connected to the source electrode of No. 1 metal-oxide-semiconductor by working state controlling circuit.The grid of No. 1 metal-oxide-semiconductor connects the grid of No. 2 metal-oxide-semiconductors, and the drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 3 metal-oxide-semiconductors.The source electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 6 metal-oxide-semiconductors, and the drain electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 4 metal-oxide-semiconductors.The source electrode of No. 3 metal-oxide-semiconductors connects power supply, and the grid of No. 3 metal-oxide-semiconductors is practiced the drain electrode of No. 5 metal-oxide-semiconductors of level.The grid of No. 4 metal-oxide-semiconductors connects the grid of No. 5 metal-oxide-semiconductors, and the source electrode of No. 4 metal-oxide-semiconductors connects power supply.The grid of No. 5 metal-oxide-semiconductors connects the grid of No. 3 metal-oxide-semiconductors, and the source electrode of No. 5 metal-oxide-semiconductors connects power supply.The grid of No. 6 metal-oxide-semiconductors connects power supply, the source ground of No. 6 metal-oxide-semiconductors.The grid of No. 7 metal-oxide-semiconductors connects the drain electrode of No. 1 metal-oxide-semiconductor, and the source electrode of No. 7 metal-oxide-semiconductors connects the source electrode of No. 2 metal-oxide-semiconductors.
Be applied in the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, detection signal comparison circuit comprises synchronous metal-oxide-semiconductor control signal output, 1 to No. 5 metal-oxide-semiconductor.Wherein the grid of No. 1 metal-oxide-semiconductor connects the grid of No. 2 metal-oxide-semiconductors, and the source electrode of No. 1 metal-oxide-semiconductor connects power supply.The drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 7 metal-oxide-semiconductors in detection signal change-over circuit.The source electrode of No. 2 metal-oxide-semiconductors connects power supply, and the drain electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 3 metal-oxide-semiconductors.The grid of No. 3 metal-oxide-semiconductors connects the drain electrode of No. 4 metal-oxide-semiconductors, and the drain electrode of No. 3 metal-oxide-semiconductors connects synchronous metal-oxide-semiconductor control signal output.The grid of No. 4 metal-oxide-semiconductors connects the grid of No. 5 metal-oxide-semiconductors, and the drain electrode of No. 4 metal-oxide-semiconductors connects power supply.The drain electrode of No. 5 metal-oxide-semiconductors connects the grid of No. 4 metal-oxide-semiconductors in detection signal change-over circuit.The grid of No. 5 metal-oxide-semiconductors connects the grid of No. 3 metal-oxide-semiconductors, the source ground of No. 5 metal-oxide-semiconductors.
The utility model is mainly used in the inductive current zero passage detection of Switching Power Supply synchronous rectifier converter, when converter works in discontinous mode, zero cross detection circuit will detect the mistake nought state of inductive current automatically, and turn-offs in time synchronous metal-oxide-semiconductor, prevents that electric current from pouring in down a chimney the generation of phenomenon.By the design to zero cross detection circuit structure, output signal is only decided by parameter and the bias current of metal-oxide-semiconductor in circuit.Therefore, the variation at the variation of ambient temperature and manufacture craft angle is minimum on the impact of the utility model output signal.
Accompanying drawing explanation
Fig. 1 is system architecture diagram of the present utility model;
Fig. 2 is the connecting circuit figure of the utility model in switching power converters;
Fig. 3 is structural circuit figure of the present utility model;
Fig. 4 is output voltage and the test point current relationship figure of the utility model at varying environment temperature;
Embodiment
For the ease of understanding the utility model, below in conjunction with the drawings and specific embodiments, the utility model is described in detail.In this specification and accompanying drawing thereof, provided preferred embodiment of the present utility model, still, the utility model can be realized in many different forms, is not limited to the described embodiment of this specification.On the contrary, providing the object of these embodiment is to make to the understanding of disclosure of the present utility model more thoroughly comprehensively.
It should be noted that, when a certain element is fixed on another element, comprise this element is directly fixed on to this another element, or this element is fixed on to this another element by least one other element placed in the middle.When an element connects another element, comprise this element is directly connected to this another element, or this element is connected to this another element by least one other element placed in the middle.
As shown in Figure 1, the zero cross detection circuit that is applied to Switching Power Supply synchronous rectifier converter comprises working state controlling circuit, detection signal change-over circuit and detection signal comparison circuit.Wherein working state controlling circuit receives main switch metal-oxide-semiconductor and drives signal Vd, and exports control signal Vcol to detection signal change-over circuit.The operating state of working state controlling circuit judgement converter, and determine that zero cross detection circuit is in high-impedance state or zero passage detection state.Detection signal change-over circuit receives zero passage detection point signal Vz, and exports comparison signal Icop to detection signal comparison circuit.Detection signal comparison circuit judges whether zero passage of test point signal, and output signal Vout controls turning on and off of synchronous metal-oxide-semiconductor.
As shown in Figure 2, the drain electrode of main switch metal-oxide-semiconductor M1 connects power supply, and the source electrode of main switch metal-oxide-semiconductor connects No. 1 port of inductance L 1.The drain electrode of synchronous metal-oxide-semiconductor M2 connects No. 1 port of inductance L 1, the source ground of synchronous metal-oxide-semiconductor M2.The forward output of metal-oxide-semiconductor drive circuit connects the grid of main switch metal-oxide-semiconductor M1, and the reversed-phase output of metal-oxide-semiconductor drive circuit is by connecting and synchronize the grid of metal-oxide-semiconductor M2 with the upper input of door AND.The zero passage detection point signal Vz receiving terminal of zero cross detection circuit connects No. 1 port of inductance L 1, and the main switch metal-oxide-semiconductor of zero cross detection circuit drives signal Vd to accept port connection drive circuit signal output part.The signal Vout output port of zero cross detection circuit is by connecting and synchronize the grid of metal-oxide-semiconductor M2 with the lower input of door AND.The signal collecting when the zero passage detection point signal Vz of zero cross detection circuit receiving terminal lower than set threshold value time, the output signal Vout of zero cross detection circuit is low level, synchronous metal-oxide-semiconductor M2 is turned off.When zero passage test point signal is greater than threshold value, the output signal Vout of zero cross detection circuit is high level, and the on off state of synchronous metal-oxide-semiconductor M2 is controlled by drive circuit.
As shown in Figure 3, port Vd, port Vz, metal-oxide-semiconductor NT1 and metal-oxide-semiconductor NT2 form working state controlling circuit jointly.Its middle port Vd receives main switch metal-oxide-semiconductor and drives signal, and port Vz receives zero passage detection point signal.Port Vd connects the grid of metal-oxide-semiconductor NT1 by inverter, port Vd connects the grid of metal-oxide-semiconductor NT2.Port Vz connects the source electrode of metal-oxide-semiconductor NT1.The drain electrode of metal-oxide-semiconductor NT1 connects the drain electrode of metal-oxide-semiconductor NT2, the source ground of metal-oxide-semiconductor NT2.When the conducting of main switch metal-oxide-semiconductor, port Vd receives high level signal, and metal-oxide-semiconductor NT1 disconnects, metal-oxide-semiconductor NT2 conducting.Due to the disconnection of metal-oxide-semiconductor NT1 and the conducting of metal-oxide-semiconductor NT2, test point signal is isolated, and zero cross detection circuit output low level does not affect converter and normally works.
Metal-oxide-semiconductor MS1 forms detection signal change-over circuit jointly to metal-oxide-semiconductor MS7, and its middle port Vz is connected to the source electrode of metal-oxide-semiconductor MS5 by working state controlling circuit.The grid of metal-oxide-semiconductor MS5 connects the grid of metal-oxide-semiconductor MS4, and the drain electrode of metal-oxide-semiconductor MS5 connects the drain electrode of metal-oxide-semiconductor MS3.The source electrode of metal-oxide-semiconductor MS4 connects the drain electrode of metal-oxide-semiconductor MS7, and the drain electrode of metal-oxide-semiconductor MS4 connects the drain electrode of metal-oxide-semiconductor MS2.The source electrode of metal-oxide-semiconductor MS3 connects power supply, and the grid of metal-oxide-semiconductor MS3 is practiced the drain electrode of level metal-oxide-semiconductor MS1.The grid of metal-oxide-semiconductor MS2 connects the grid of metal-oxide-semiconductor MS1, and the source electrode of metal-oxide-semiconductor MS2 connects power supply.The grid of metal-oxide-semiconductor MS1 connects the grid of metal-oxide-semiconductor MS3, and the source electrode of metal-oxide-semiconductor MS1 connects power supply.The grid of metal-oxide-semiconductor MS7 connects power supply, the source ground of metal-oxide-semiconductor MS7.The grid of metal-oxide-semiconductor MS6 connects the drain electrode of metal-oxide-semiconductor MS5, and the source electrode of metal-oxide-semiconductor MS6 connects the source electrode of metal-oxide-semiconductor MS4.Detection signal change-over circuit is converted to the test point voltage signal receiving the current signal of corresponding proportion, and comparison signal Icop is outputed to detection signal comparison circuit and setting threshold compares, and then the operating state of judgement converter.
Output port Vout, metal-oxide-semiconductor ME1 to ME5 form detection signal comparison circuit jointly, and wherein the grid of metal-oxide-semiconductor ME1 connects the grid of metal-oxide-semiconductor ME2, and the source electrode of metal-oxide-semiconductor ME1 connects power supply.The drain electrode of metal-oxide-semiconductor ME1 connects the drain electrode of metal-oxide-semiconductor MS6 in detection signal change-over circuit.The source electrode of metal-oxide-semiconductor ME2 connects power supply, and the drain electrode of metal-oxide-semiconductor ME2 connects the drain electrode of metal-oxide-semiconductor ME3.The grid of metal-oxide-semiconductor ME3 connects the drain electrode of metal-oxide-semiconductor ME4, and the drain electrode of metal-oxide-semiconductor ME3 connects signal output part Vout.The grid of metal-oxide-semiconductor ME4 connects the grid of metal-oxide-semiconductor ME5, and the drain electrode of metal-oxide-semiconductor ME4 connects power supply.The drain electrode of metal-oxide-semiconductor ME5 connects the grid of metal-oxide-semiconductor MS2 in detection signal change-over circuit.The grid of metal-oxide-semiconductor ME5 connects the grid of metal-oxide-semiconductor ME3, the source ground of metal-oxide-semiconductor ME5.
The threshold value of detection signal comparison circuit is I (R
nT2-2R
nT1)/R
m2.R wherein
nT1for the on state resistance of metal-oxide-semiconductor NT1, R
nT2for the on state resistance of metal-oxide-semiconductor NT2, R
m2for the on state resistance of synchronous metal-oxide-semiconductor, I is the electric current that flows through the metal-oxide-semiconductor drain-source utmost point.When test point signal is less than threshold value, port Vout output low level, synchronous metal-oxide-semiconductor turn-offs.When test point signal is greater than threshold value, port Vout exports high level, and synchronous metal-oxide-semiconductor is controlled by drive circuit.
As shown in Figure 4, the relation of the zero cross detection circuit that is applied to Switching Power Supply synchronous rectifier converter output voltage V out and checkpoint current signal Icop at varying environment temperature.Wherein, power source voltage Vcc is 5V, and it is low level that main switch metal-oxide-semiconductor drives signal Vd.Respectively four temperature spots are detected, wherein the detected temperatures of curve A point is 150 degrees Celsius, and the detected temperatures point of curve B is 90 degrees Celsius, and the detected temperatures point of curve C is 35 degrees Celsius, and the detected temperatures point of curve D is-50.As seen from Figure 4, the mean value of the test point current signal Icop of output voltage V out generation upset is 35.3mA.For different detected temperatures points, the relative error that the test point current signal Icop of upset occurs output voltage V out is 0.5mA to the maximum.Visible, the structural design that is applied to the zero cross detection circuit of Switching Power Supply synchronous rectifier converter makes ambient temperature minimum on the impact of output voltage V out.
Further, embodiment of the present utility model also comprises, each technical characterictic of the various embodiments described above, the zero cross detection circuit that is applied to Switching Power Supply synchronous rectifier converter being mutually combined to form.
It should be noted that, above-mentioned each technical characterictic continues combination mutually, forms the various embodiment that do not enumerate in the above, is all considered as the scope that the utility model specification is recorded; And, for those of ordinary skills, can be improved according to the above description or convert, and all these improvement and conversion all should belong to the protection range of the utility model claims.
Claims (7)
1. a zero cross detection circuit that is applied to Switching Power Supply synchronous rectifier converter, is characterized in that, it comprises working state controlling circuit, detection signal change-over circuit and detection signal comparison circuit;
Working state controlling circuit receives main switch metal-oxide-semiconductor and drives signal, and output services state control signal is in detection signal change-over circuit;
Detection signal change-over circuit receives zero passage detection point signal, and exports comparison signal in detection signal comparison circuit;
Detection signal outputs to the grid of synchronous metal-oxide-semiconductor using comparative result as control signal.
2. be applied to according to claim 1 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, working state controlling circuit comprises main switch metal-oxide-semiconductor driving signal input, inverter, No. 1 metal-oxide-semiconductor and No. 2 metal-oxide-semiconductors.
3. be applied to according to claim 2 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, main switch metal-oxide-semiconductor driving signal input connects the input of inverter, and connects the grid of No. 2 metal-oxide-semiconductors;
The output of inverter connects the grid of No. 1 metal-oxide-semiconductor, and the drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 2 metal-oxide-semiconductors; The source ground of No. 2 metal-oxide-semiconductors.
4. be applied to according to claim 1 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, detection signal change-over circuit comprises zero passage detection point signal input part, 1 to No. 7 metal-oxide-semiconductor.
5. be applied to according to claim 4 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, zero passage detection point signal input part is connected to the source electrode of No. 1 metal-oxide-semiconductor by working state controlling circuit;
The grid of No. 1 metal-oxide-semiconductor connects the grid of No. 2 metal-oxide-semiconductors, and the drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 3 metal-oxide-semiconductors;
The source electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 6 metal-oxide-semiconductors, and the drain electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 4 metal-oxide-semiconductors;
The source electrode of No. 3 metal-oxide-semiconductors connects power supply, and the grid of No. 3 metal-oxide-semiconductors is practiced the drain electrode of No. 5 metal-oxide-semiconductors of level; The grid of No. 4 metal-oxide-semiconductors connects the grid of No. 5 metal-oxide-semiconductors, and the source electrode of No. 4 metal-oxide-semiconductors connects power supply;
The grid of No. 5 metal-oxide-semiconductors connects the grid of No. 3 metal-oxide-semiconductors, and the source electrode of No. 5 metal-oxide-semiconductors connects power supply; The grid of No. 6 metal-oxide-semiconductors connects power supply, the source ground of No. 6 metal-oxide-semiconductors;
The grid of No. 7 metal-oxide-semiconductors connects the drain electrode of No. 1 metal-oxide-semiconductor, and the source electrode of No. 7 metal-oxide-semiconductors connects the source electrode of No. 2 metal-oxide-semiconductors.
6. be applied to according to claim 1 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, detection signal comparison circuit comprises synchronous metal-oxide-semiconductor control signal output, 1 to No. 5 metal-oxide-semiconductor.
7. be applied to according to claim 6 the zero cross detection circuit of Switching Power Supply synchronous rectifier converter, it is characterized in that, the grid of No. 1 metal-oxide-semiconductor connects the grid of No. 2 metal-oxide-semiconductors, and the source electrode of No. 1 metal-oxide-semiconductor connects power supply;
The drain electrode of No. 1 metal-oxide-semiconductor connects the drain electrode of No. 7 metal-oxide-semiconductors in detection signal change-over circuit;
The source electrode of No. 2 metal-oxide-semiconductors connects power supply, and the drain electrode of No. 2 metal-oxide-semiconductors connects the drain electrode of No. 3 metal-oxide-semiconductors;
The grid of No. 3 metal-oxide-semiconductors connects the drain electrode of No. 4 metal-oxide-semiconductors, and the drain electrode of No. 3 metal-oxide-semiconductors connects synchronous metal-oxide-semiconductor control signal output;
The grid of No. 4 metal-oxide-semiconductors connects the grid of No. 5 metal-oxide-semiconductors, and the drain electrode of No. 4 metal-oxide-semiconductors connects power supply;
The drain electrode of No. 5 metal-oxide-semiconductors connects the grid of No. 4 metal-oxide-semiconductors in detection signal change-over circuit;
The grid of No. 5 metal-oxide-semiconductors connects the grid of No. 3 metal-oxide-semiconductors, the source ground of No. 5 metal-oxide-semiconductors.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420324787.2U CN203911793U (en) | 2014-06-18 | 2014-06-18 | Zero-cross detection circuit applied to switch power supply synchronous rectification converter |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420324787.2U CN203911793U (en) | 2014-06-18 | 2014-06-18 | Zero-cross detection circuit applied to switch power supply synchronous rectification converter |
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| CN203911793U true CN203911793U (en) | 2014-10-29 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105356759A (en) * | 2015-12-13 | 2016-02-24 | 魏腾飞 | PWM control method for bidirectional full-bridge DC-DC converter |
-
2014
- 2014-06-18 CN CN201420324787.2U patent/CN203911793U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105356759A (en) * | 2015-12-13 | 2016-02-24 | 魏腾飞 | PWM control method for bidirectional full-bridge DC-DC converter |
| CN105356759B (en) * | 2015-12-13 | 2019-01-22 | 魏腾飞 | A kind of PWM control method of two-way full-bridge DC-DC converter |
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