CN203883691U - Current zero-crossing point detection circuit, drive circuit, and switching power supply - Google Patents
Current zero-crossing point detection circuit, drive circuit, and switching power supply Download PDFInfo
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- CN203883691U CN203883691U CN201320827726.3U CN201320827726U CN203883691U CN 203883691 U CN203883691 U CN 203883691U CN 201320827726 U CN201320827726 U CN 201320827726U CN 203883691 U CN203883691 U CN 203883691U
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Abstract
The utility model discloses a current zero-crossing point detection circuit, a drive circuit, and a switching power supply. The current zero-crossing point detection circuit is applied to the switching power supply. The switching power supply comprises a rectifier bridge, a first power switching tube, a second power switching tube, and an on-off control circuit. The current zero-crossing point detection circuit is connected in series between the source electrode of the first power switching tube and the input end of the on-off control circuit, and is used for detecting the descending slope of a voltage of the source electrode of the first power switching tube, comparing the descending slope into a first voltage which is compared with a preset voltage, outputting a current zero-crossing point signal of a secondary diode to the on-off control circuit, and controlling the on/off of the second power switching tube. Therefore, the circuit provided by the utility model can achieve the detection of current zero-crossing information of the secondary diode, does not need an independent transformer to assist a winding, is small in occupied space, and is low in cost.
Description
Technical field
The utility model relates to LED field, in particular, relates to a kind of current zero-crossing point testing circuit, drive circuit and Switching Power Supply.
Background technology
Fig. 1 is the rough schematic view of traditional inverse-excitation type LED drive circuit, as shown in Figure 1, alternating current through capacitor C1 filtering, produces a direct voltage after rectifier bridge rectification, produce a low-voltage DC through resistance R 1 and capacitor C2 again control chip is started, power ratio control switching tube M1 opens.And the transformer of this drive circuit has three windings, wherein, former limit winding is connected between the output of rectifier bridge and the drain electrode of power switch pipe M1, and the Same Name of Ends of secondary winding is connected with the anode of secondary diode D1, and auxiliary winding is connected between diode D2 and ground.
From the figure not difficult to find, traditional inverse-excitation type LED drive circuit is to be control chip power supply by auxiliary winding, and auxiliary winding is also for detection of the current zero-crossing point of secondary diode D1 and the information of output voltage overvoltage simultaneously.
But above-mentioned auxiliary winding can increase volume and the cost of drive circuit, be not suitable for existing market LED small size, development trend cheaply.Therefore, how can realize the current over-zero dot information that detects secondary diode, can make again drive circuit take volume little is current problem demanding prompt solution.
Utility model content
In view of this, the utility model provides a kind of current zero-crossing point testing circuit, can realize the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that its circuit takies volume.
For achieving the above object, the utility model provides following technical scheme:
A kind of current zero-crossing point testing circuit, is applied to Switching Power Supply, and described Switching Power Supply comprises: rectifier bridge, the first power switch pipe, the second power switch pipe and ON-OFF control circuit,
Described current zero-crossing point testing circuit is serially connected between the source electrode of described the first power switch pipe and the input of described ON-OFF control circuit, for detection of the descending slope of the source voltage of described the first power switch pipe, and described descending slope is converted into the first voltage and predeterminated voltage compares, export a level diode current crossover point signal to described ON-OFF control circuit, control unlatching or the shutoff of described the second power switch pipe.
Preferably, comprising: the first electric capacity, current detection circuit, electric current turn potential circuit and comparator;
The first end of described the first electric capacity is connected with the source electrode of described the first power switch pipe, and in the time that the source voltage of described the first power switch pipe declines, described the first capacitor discharge, produces the first electric current;
The input of described current detection circuit is connected with the second end of described the first electric capacity, detects described the first electric current;
Described electric current turns the input of potential circuit and the output of described current detection circuit is connected, and described the first electric current is converted into described the first voltage;
The in-phase input end of described comparator connects described predeterminated voltage, the inverting input of described comparator is connected with the output that described electric current turns potential circuit, for the size of more described the first voltage and described predeterminated voltage, produce described secondary diode current zero-crossing point signal.
Preferably, described current detection circuit comprises: the first metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the second electric capacity;
The source electrode of described the first metal-oxide-semiconductor connects external voltage, the grid of described the first metal-oxide-semiconductor is as the output of described current detection circuit, the drain electrode of described the first metal-oxide-semiconductor is connected with the first end of described the second electric capacity and the grid of described the first metal-oxide-semiconductor respectively, the second end of described the second electric capacity is connected with the source electrode of described the second metal-oxide-semiconductor, the drain electrode of described the second metal-oxide-semiconductor is as the input of described current detection circuit, and the grid of described the second metal-oxide-semiconductor connects bias voltage.
Preferably, described electric current turns potential circuit and comprises: the second metal-oxide-semiconductor, the 3rd electric capacity and the first resistance;
The source electrode of described the second metal-oxide-semiconductor connects external voltage, the grid of described the second metal-oxide-semiconductor turns the input of potential circuit as described electric current, the drain electrode of described the second metal-oxide-semiconductor is connected with the first end of described the 3rd electric capacity and the first end of described the first resistance respectively, and turn the output of potential circuit as described electric current, the equal ground connection of the second end of the second end of described the 3rd electric capacity and described the first resistance.
Preferably, described predeterminated voltage is the reference voltage that reference voltage source produces.
A kind of drive circuit, comprising: rectifier bridge, the first power switch pipe, the second power switch pipe, ON-OFF control circuit and current zero-crossing point testing circuit;
The output of described rectifier bridge is by described the first power switch pipe and the described second power switch pipe ground connection of serial connection;
Described current zero-crossing point testing circuit is serially connected between the source electrode of described the first power switch pipe and the input of described ON-OFF control circuit;
The output of described ON-OFF control circuit is connected with the grid of described the second power switch pipe, and the control end of described ON-OFF control circuit is connected with the source electrode of described the second power switch pipe.
Preferably, described current zero-crossing point testing circuit comprises: the first electric capacity, current detection circuit, electric current turn potential circuit and comparator;
The first end of described the first electric capacity is connected with the source electrode of described the first power switch pipe, and in the time that the source voltage of described the first power switch pipe declines, described the first capacitor discharge, produces the first electric current;
The input of described current detection circuit is connected with the second end of described the first electric capacity, detects described the first electric current;
Described electric current turns the input of potential circuit and the output of described current detection circuit is connected, and described the first electric current is converted into described the first voltage;
The in-phase input end of described comparator connects described predeterminated voltage, the inverting input of described comparator is connected with the output that described electric current turns potential circuit, for the size of more described the first voltage and described predeterminated voltage, produce described secondary diode current zero-crossing point signal.
Preferably, described current detection circuit comprises: the first metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the second electric capacity;
The source electrode of described the first metal-oxide-semiconductor connects external voltage, the grid of described the first metal-oxide-semiconductor is as the output of described current detection circuit, the drain electrode of described the first metal-oxide-semiconductor is connected with the first end of described the second electric capacity and the grid of described the first metal-oxide-semiconductor respectively, the second end of described the second electric capacity is connected with the source electrode of described the second metal-oxide-semiconductor, the drain electrode of described the second metal-oxide-semiconductor is as the input of described current detection circuit, and the grid of described the second metal-oxide-semiconductor connects bias voltage.
Preferably, described electric current turns potential circuit and comprises: the second metal-oxide-semiconductor, the 3rd electric capacity and the first resistance;
The source electrode of described the second metal-oxide-semiconductor connects external voltage, the grid of described the second metal-oxide-semiconductor turns the input of potential circuit as described electric current, the drain electrode of described the second metal-oxide-semiconductor is connected with the first end of described the 3rd electric capacity and the first end of described the first resistance respectively, and turn the output of potential circuit as described electric current, the equal ground connection of the second end of the second end of described the 3rd electric capacity and described the first resistance.
A kind of Switching Power Supply, comprises the current zero-crossing point testing circuit described in any one.
That is, the utility model provides a kind of current zero-crossing point testing circuit, is applied to Switching Power Supply, and this Switching Power Supply comprises: rectifier bridge, the first power switch pipe, the second power switch pipe and ON-OFF control circuit.This current zero-crossing point testing circuit is serially connected between the source electrode of the first power switch pipe and the input of ON-OFF control circuit, for detection of the descending slope of the source voltage of the first power switch pipe, and descending slope is converted into the first voltage and predeterminated voltage compares, export a level diode current crossover point signal to ON-OFF control circuit, control unlatching or the shutoff of the second power switch pipe.The current zero-crossing point testing circuit visible, the utility model provides, can realize the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that its circuit takies volume, and cost is low.
Brief description of the drawings
In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only embodiment of the present utility model, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, other accompanying drawing can also be provided according to the accompanying drawing providing.
Fig. 1 is the circuit theory diagrams of LED driving power in prior art;
The structural representation of a kind of drive circuit that Fig. 2 forms for a kind of current zero-crossing point testing circuit being provided by the utility model;
The structural representation of the current detection circuit in a kind of current zero-crossing point testing circuit that Fig. 3 provides for the utility model;
Electric current in a kind of current zero-crossing point testing circuit that Fig. 4 provides for the utility model turns the structural representation of potential circuit;
Fig. 5 is for adopting after a kind of current zero-crossing point testing circuit of providing of the utility model, the waveform schematic diagram of each signal.
Embodiment
Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is clearly and completely described, obviously, described embodiment is only a part of embodiment of the present utility model, instead of whole embodiment.Based on the embodiment in the utility model, those of ordinary skill in the art are not making the every other embodiment obtaining under creative work prerequisite, all belong to the scope of the utility model protection.
The utility model provides a kind of current zero-crossing point testing circuit, can realize the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that its circuit takies volume.
Embodiment mono-
Refer to Fig. 2, the structural representation of the drive circuit that a kind of current zero-crossing point testing circuit providing for the utility model forms, this current zero-crossing point testing circuit is applied to Switching Power Supply.Wherein, Switching Power Supply comprises: rectifier bridge DB1, the first power switch pipe M1, the second power switch pipe M2 and ON-OFF control circuit 104.
This current zero-crossing point testing circuit is serially connected between the source electrode of the first power switch pipe M1 and the input of ON-OFF control circuit 104, for detection of the descending slope of the source voltage of the first power switch pipe, and descending slope is converted into the first voltage and predeterminated voltage compares, export a level diode current crossover point signal to ON-OFF control circuit, control unlatching or the shutoff of the second power switch pipe.
Be not difficult to find from Fig. 2, the current zero-crossing point testing circuit that the utility model provides, does not need to adopt independent transformer to assist winding, and it is little that its circuit takies volume, and cost is low.
Concrete, the present embodiment provides a kind of specific implementation circuit of current zero-crossing point testing circuit, comprising: the first capacitor C 4, current detection circuit 101, electric current turn potential circuit 102 and comparator 103.
Its circuit connecting relation is:
The first end of the first electric capacity is connected with the source electrode of the first power switch pipe, and in the time that the source voltage of the first power switch pipe declines, the first capacitor discharge, produces the first electric current.The input of current detection circuit is connected with the second end of the first electric capacity, detects the first electric current.Electric current turns the input of potential circuit and the output of current detection circuit is connected, and the first electric current is converted into the first voltage.The in-phase input end of comparator connects predeterminated voltage, and the inverting input of comparator is connected with the output that electric current turns potential circuit, for comparing the size of the first voltage and predeterminated voltage, produces secondary diode current zero-crossing point signal.
Here it should be noted that, current detection circuit 101 and electric current turn potential circuit 102 realize circuit have a variety of, in the present embodiment, not particularize.Those skilled in the art are inwardly of the present utility model, within current detection circuit and electric current being turned to the selecting and all belong to protection range of the present utility model of different structure of potential circuit.
Preferably, the present embodiment provides a kind of concrete current detection circuit, as shown in Figure 3, comprising: the first metal-oxide-semiconductor P1, the 3rd metal-oxide-semiconductor P3 and the second capacitor C C1.
The annexation of each device is:
The source electrode of the first metal-oxide-semiconductor connects external voltage, the grid of the first metal-oxide-semiconductor is as the output of current detection circuit, the drain electrode of the first metal-oxide-semiconductor is connected with the first end of the second electric capacity and the grid of the first metal-oxide-semiconductor respectively, the second end of the second electric capacity is connected with the source electrode of the second metal-oxide-semiconductor, the drain electrode of the second metal-oxide-semiconductor is as the input of current detection circuit, and the grid of the second metal-oxide-semiconductor connects bias voltage.
Its current detecting principle is: in the time that input Iin has electric current outwards to flow out, this electric current can be detected by the first metal-oxide-semiconductor P1, realize the effect of current detecting.It should be noted that, wherein, Vb is the built-in bias voltage of drive circuit.
Same, the present embodiment also provides a kind of concrete electric current to turn potential circuit, as shown in Figure 4, comprising: the second metal-oxide-semiconductor P2, the 3rd capacitor C C2 and the first resistance R R1.
This electric current turns in potential circuit, and the annexation of each device is as follows:
The source electrode of the second metal-oxide-semiconductor connects external voltage, the grid of the second metal-oxide-semiconductor turns the input of potential circuit as electric current, the drain electrode of the second metal-oxide-semiconductor is connected with the first end of the 3rd electric capacity and the first end of the first resistance respectively, and turn the output of potential circuit as electric current, the equal ground connection of the second end of the second end of the 3rd electric capacity and the first resistance.
The operation principle that its electric current turns voltage is: the electric current being detected by the first metal-oxide-semiconductor flow into the 3rd capacitor C C2 and the first resistance R R1 by the second metal-oxide-semiconductor P2, after the filtering of the 3rd capacitor C C2 and the first resistance R R1 is processed, is converted into the first voltage Vo.
Afterwards this first voltage Vo and predeterminated voltage Vref are compared, comparator 103 produces a level diode current crossover point signal to ON-OFF control circuit 104.
It should be noted that, predeterminated voltage Vref in above-mentioned current zero-crossing point testing circuit can be the reference voltage that the reference voltage source of drive circuit inside produces, also can be the reference voltage being produced by external voltage source, the production process of predeterminated voltage not limited in the present embodiment.
The current zero-crossing point testing circuit visible, the utility model provides, can realize the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that its circuit takies volume, and cost is low.
Embodiment bis-
On the basis of above-described embodiment one, the present embodiment provides a kind of drive circuit, comprising: rectifier bridge, the first power switch pipe, the second power switch pipe, ON-OFF control circuit and above-mentioned current zero-crossing point testing circuit.
Wherein, the output of rectifier bridge is by the first power switch pipe and the second power switch pipe ground connection of serial connection.Current zero-crossing point testing circuit is serially connected between the source electrode of the first power switch pipe and the input of ON-OFF control circuit.The output of ON-OFF control circuit is connected with the grid of the second power switch pipe, and the control end of ON-OFF control circuit is connected with the source electrode of the second power switch pipe.
Here it should be noted that, circuit structure and the operation principle of the current zero-crossing point testing circuit in the present embodiment are identical with embodiment mono-.Concrete, incorporated by reference to Fig. 2 and Fig. 5, the operation principle of this drive circuit is introduced, as follows:
In the time of the second power switch pipe M2 conducting, the first also conducting of power switch pipe M1, now the primary current of transformer rises, voltage on sampling resistor R2 also rises, in the time that the voltage on sampling resistor R2 reaches pre-set threshold value, ON-OFF control circuit 104 is exported control signal, and the second power switch pipe M2 is closed, and the first power switch pipe M1 also disconnects simultaneously.Now, feedback stream diode D5 conducting, the source voltage that makes the first power switch pipe M1 is by clamp to Vcc, and the secondary diode D1 of transformer secondary starts conducting simultaneously, electric current I second on secondary diode D1 rises to very soon peak value and starts and declines, as the t1-t2 moment in Fig. 5.
In the time that the electric current of secondary diode D1 drops to zero, as the t2 moment in Fig. 5, the drain voltage of the first power switch pipe M1 starts to decline, due to the drain electrode of the first power switch pipe M1 and the capacitive coupling effect of source electrode, the source voltage of the first power switch pipe M1 also starts to decline, and the Out terminal voltage in corresponding diagram 5 declines.
It should be noted that, the capacitive coupling of this first power switch pipe M1, can be between the source electrode of the first power switch pipe M1 and drain electrode and connect an external capacitor and be coupled, can be to be also coupled by the parasitic capacitance between source electrode and the drain electrode of the first power switch pipe M1.
In the time that Out point voltage declines, have the electric current generation that flows into the source electrode of the first power switch pipe M1 from the first capacitor C 4, i.e. the first electric current.This first electric current can be gathered by current detection circuit 101, and turn potential circuit 102 by electric current this first electric current is converted into the first voltage Vo, now, comparator 103 compares this first voltage Vo and predeterminated voltage Vref, and output one controls signal to ON-OFF control circuit 104.
In conjunction with Fig. 5, in the present embodiment, the moment finishing at secondary diode ON time Tons, it is the current over-zero moment of secondary diode, electric current turns the first voltage Vo that potential circuit 104 exports and sharply rises and exceed predeterminated voltage Vref, and now, comparator 103 overturns, therefore, defining above-mentioned control signal is secondary diode current zero-crossing point signal.
To sum up, the drive circuit that the present embodiment provides also can both be realized the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that circuit takies volume, and cost is low.
Except this, the present embodiment also provides a kind of Switching Power Supply, comprises the current zero-crossing point testing circuit that any one is above-mentioned.
To sum up, the utility model provides a kind of current zero-crossing point testing circuit, is applied to Switching Power Supply, and this Switching Power Supply comprises: rectifier bridge, the first power switch pipe, the second power switch pipe and ON-OFF control circuit.This current zero-crossing point testing circuit is serially connected between the source electrode of the first power switch pipe and the input of ON-OFF control circuit, for detection of the descending slope of the source voltage of the first power switch pipe, and descending slope is converted into the first voltage and predeterminated voltage compares, export a level diode current crossover point signal to ON-OFF control circuit, control unlatching or the shutoff of the second power switch pipe.The current zero-crossing point testing circuit visible, the utility model provides, can realize the current over-zero dot information that detects secondary diode, does not need again to adopt independent transformer to assist winding, and it is little that its circuit takies volume, and cost is low.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and what each embodiment stressed is and the difference of other embodiment, between each embodiment identical similar part mutually referring to.For the device providing for embodiment, because its method providing with embodiment is corresponding, so description is fairly simple, relevant part illustrates referring to method part.
To the above-mentioned explanation of provided embodiment, make professional and technical personnel in the field can realize or use the utility model.To be apparent for those skilled in the art to the multiple amendment of these embodiment, General Principle as defined herein can, in the situation that not departing from spirit or scope of the present utility model, realize in other embodiments.Therefore, the utility model will can not be restricted to these embodiment shown in this article, but will meet the widest scope consistent with principle provided in this article and features of novelty.
Claims (10)
1. a current zero-crossing point testing circuit, is applied to Switching Power Supply, and described Switching Power Supply comprises: rectifier bridge, the first power switch pipe, the second power switch pipe and ON-OFF control circuit, is characterized in that:
Described current zero-crossing point testing circuit is serially connected between the source electrode of described the first power switch pipe and the input of described ON-OFF control circuit, for detection of the descending slope of the source voltage of described the first power switch pipe, and described descending slope is converted into the first voltage and predeterminated voltage compares, export a level diode current crossover point signal to described ON-OFF control circuit, control unlatching or the shutoff of described the second power switch pipe.
2. current zero-crossing point testing circuit according to claim 1, is characterized in that, comprising: the first electric capacity, current detection circuit, electric current turn potential circuit and comparator;
The first end of described the first electric capacity is connected with the source electrode of described the first power switch pipe, and in the time that the source voltage of described the first power switch pipe declines, described the first capacitor discharge, produces the first electric current;
The input of described current detection circuit is connected with the second end of described the first electric capacity, detects described the first electric current;
Described electric current turns the input of potential circuit and the output of described current detection circuit is connected, and described the first electric current is converted into described the first voltage;
The in-phase input end of described comparator connects described predeterminated voltage, the inverting input of described comparator is connected with the output that described electric current turns potential circuit, for the size of more described the first voltage and described predeterminated voltage, produce described secondary diode current zero-crossing point signal.
3. current zero-crossing point testing circuit according to claim 2, is characterized in that, described current detection circuit comprises: the first metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the second electric capacity;
The source electrode of described the first metal-oxide-semiconductor connects external voltage, the grid of described the first metal-oxide-semiconductor is as the output of described current detection circuit, the drain electrode of described the first metal-oxide-semiconductor is connected with the first end of described the second electric capacity and the grid of described the first metal-oxide-semiconductor respectively, the second end of described the second electric capacity is connected with the source electrode of described the 3rd metal-oxide-semiconductor, the drain electrode of described the 3rd metal-oxide-semiconductor is as the input of described current detection circuit, and the grid of described the 3rd metal-oxide-semiconductor connects bias voltage.
4. current zero-crossing point testing circuit according to claim 2, is characterized in that, described electric current turns potential circuit and comprises: the second metal-oxide-semiconductor, the 3rd electric capacity and the first resistance;
The source electrode of described the second metal-oxide-semiconductor connects external voltage, the grid of described the second metal-oxide-semiconductor turns the input of potential circuit as described electric current, the drain electrode of described the second metal-oxide-semiconductor is connected with the first end of described the 3rd electric capacity and the first end of described the first resistance respectively, and turn the output of potential circuit as described electric current, the equal ground connection of the second end of the second end of described the 3rd electric capacity and described the first resistance.
5. current zero-crossing point testing circuit according to claim 1, is characterized in that, described predeterminated voltage is the reference voltage that reference voltage source produces.
6. a drive circuit, is characterized in that, comprising: rectifier bridge, the first power switch pipe, the second power switch pipe, ON-OFF control circuit and current zero-crossing point testing circuit;
The output of described rectifier bridge is by described the first power switch pipe and the described second power switch pipe ground connection of serial connection;
Described current zero-crossing point testing circuit is serially connected between the source electrode of described the first power switch pipe and the input of described ON-OFF control circuit;
The output of described ON-OFF control circuit is connected with the grid of described the second power switch pipe, and the control end of described ON-OFF control circuit is connected with the source electrode of described the second power switch pipe.
7. drive circuit according to claim 6, is characterized in that, described current zero-crossing point testing circuit comprises: the first electric capacity, current detection circuit, electric current turn potential circuit and comparator;
The first end of described the first electric capacity is connected with the source electrode of described the first power switch pipe, and in the time that the source voltage of described the first power switch pipe declines, described the first capacitor discharge, produces the first electric current;
The input of described current detection circuit is connected with the second end of described the first electric capacity, detects described the first electric current;
Described electric current turns the input of potential circuit and the output of described current detection circuit is connected, and described the first electric current is converted into the first voltage;
The in-phase input end of described comparator connects predeterminated voltage, and the inverting input of described comparator is connected with the output that described electric current turns potential circuit, for the size of more described the first voltage and described predeterminated voltage, produces secondary diode current zero-crossing point signal.
8. drive circuit according to claim 7, is characterized in that, described current detection circuit comprises: the first metal-oxide-semiconductor, the 3rd metal-oxide-semiconductor and the second electric capacity;
The source electrode of described the first metal-oxide-semiconductor connects external voltage, the grid of described the first metal-oxide-semiconductor is as the output of described current detection circuit, the drain electrode of described the first metal-oxide-semiconductor is connected with the first end of described the second electric capacity and the grid of described the first metal-oxide-semiconductor respectively, the second end of described the second electric capacity is connected with the source electrode of described the 3rd metal-oxide-semiconductor, the drain electrode of described the 3rd metal-oxide-semiconductor is as the input of described current detection circuit, and the grid of described the 3rd metal-oxide-semiconductor connects bias voltage.
9. drive circuit according to claim 7, is characterized in that, described electric current turns potential circuit and comprises: the second metal-oxide-semiconductor, the 3rd electric capacity and the first resistance;
The source electrode of described the second metal-oxide-semiconductor connects external voltage, the grid of described the second metal-oxide-semiconductor turns the input of potential circuit as described electric current, the drain electrode of described the second metal-oxide-semiconductor is connected with the first end of described the 3rd electric capacity and the first end of described the first resistance respectively, and turn the output of potential circuit as described electric current, the equal ground connection of the second end of the second end of described the 3rd electric capacity and described the first resistance.
10. a Switching Power Supply, is characterized in that, comprises the current zero-crossing point testing circuit as described in any one in claim 1-5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320827726.3U CN203883691U (en) | 2013-12-13 | 2013-12-13 | Current zero-crossing point detection circuit, drive circuit, and switching power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320827726.3U CN203883691U (en) | 2013-12-13 | 2013-12-13 | Current zero-crossing point detection circuit, drive circuit, and switching power supply |
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| CN203883691U true CN203883691U (en) | 2014-10-15 |
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| CN201320827726.3U Withdrawn - After Issue CN203883691U (en) | 2013-12-13 | 2013-12-13 | Current zero-crossing point detection circuit, drive circuit, and switching power supply |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103731049A (en) * | 2013-12-13 | 2014-04-16 | 上海新进半导体制造有限公司 | Current zero crossing point detection circuit and method, driving circuit and method, and switch power source |
| CN104360143A (en) * | 2014-12-04 | 2015-02-18 | 杰华特微电子（杭州）有限公司 | Load zero crossing point detection circuit and method and load voltage detection circuit and method |
| CN107005169A (en) * | 2014-12-08 | 2017-08-01 | B/E航空公司 | Quasi-resonance magnetron electric supply |
| CN107733255A (en) * | 2017-10-20 | 2018-02-23 | 福建省福芯电子科技有限公司 | A kind of double winding power circuit |
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2013
- 2013-12-13 CN CN201320827726.3U patent/CN203883691U/en not_active Withdrawn - After Issue
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103731049A (en) * | 2013-12-13 | 2014-04-16 | 上海新进半导体制造有限公司 | Current zero crossing point detection circuit and method, driving circuit and method, and switch power source |
| CN103731049B (en) * | 2013-12-13 | 2017-05-31 | 上海新进半导体制造有限公司 | Current zero-crossing point detects circuit and method, drive circuit and method, Switching Power Supply |
| CN104360143A (en) * | 2014-12-04 | 2015-02-18 | 杰华特微电子（杭州）有限公司 | Load zero crossing point detection circuit and method and load voltage detection circuit and method |
| CN104360143B (en) * | 2014-12-04 | 2017-08-08 | 杰华特微电子（杭州）有限公司 | Current zero-crossing point detects circuit and method, load voltage detection circuit and method |
| CN107005169A (en) * | 2014-12-08 | 2017-08-01 | B/E航空公司 | Quasi-resonance magnetron electric supply |
| CN107005169B (en) * | 2014-12-08 | 2020-01-31 | B/E航空公司 | Quasi-resonant magnetron power supply |
| CN107733255A (en) * | 2017-10-20 | 2018-02-23 | 福建省福芯电子科技有限公司 | A kind of double winding power circuit |
| CN107733255B (en) * | 2017-10-20 | 2024-05-28 | 福建省福芯电子科技有限公司 | Double-winding power supply circuit |
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