CN204964613U - Zero -cross detection circuit - Google Patents
Zero -cross detection circuit Download PDFInfo
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- CN204964613U CN204964613U CN201520679202.3U CN201520679202U CN204964613U CN 204964613 U CN204964613 U CN 204964613U CN 201520679202 U CN201520679202 U CN 201520679202U CN 204964613 U CN204964613 U CN 204964613U
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Abstract
The utility model discloses a be applied to electronic load's zero -cross detection circuit, including the filtering modulate circuit, comparator and output circuit, incoming signal takes care of circuit connection to comparator negative input end through filtering, the output connection of comparator to output circuit's input, output circuit's output is connected to comparator positive input terminal through positive feedback loop, its characterized in that, electric capacity has concatenated on the positive feedback loop, electric capacity constitutes integrating circuit with the ground resistance that comparator positive input terminal is connected. The utility model discloses a positive feedback loop can avoid the influence that near incoming signal shake in produced zero point to the measurement of frequency to add electric capacity and constitute integrating circuit in positive feedback loop, can make the positive feedback lose efficacy before next zero crossing through control integration time constant, the phase place time delay can not appear in output signal when making next zero crossing, guarantees next zero passage circuit signal accurate monitoring the in real time, thereby has ensured electronic load operating condition's stability.
Description
Technical field
The utility model relates to electronic load field, is particularly applied to the zero cross detection circuit of electronic load.
Background technology
Zero passage detection refers to that AC signal waveform is from just half circumferential negative half period transfer process, to its detection through zero-bit.Zero passage detection plays an important role in AC system, such as electronic load output waveform, produces reference signal or control signal with the zero crossing of voltage.Containing harmonic wave in AC signal, easily cause the zero cross signal frequency different from input signal that export or not homophase, thus affect the stability of electronic load operation.
To the zero passage detection of AC signal in prior art, normally AC signal to be detected is passed through wave filter, after filtering conditioning, the negative input end of access comparer, with the harmonic signal in this filtering AC signal, realizes the zero-crossing examination of AC signal.
Summary of the invention
It is high that the purpose of this utility model is to provide a kind of frequency detection accuracy being applied to electronic load, the zero cross detection circuit that phase delay is little.
The utility model is realized by following technical scheme:
A kind of zero cross detection circuit being applied to electronic load, comprise filtering modulate circuit, comparer and output circuit, input signal is connected to comparer negative input end through filtering modulate circuit, the output of comparer is connected to the input end of output circuit, and the output of output circuit is connected to comparer positive input terminal by positive feedback loop, it is characterized in that, described positive feedback loop is serially connected with electric capacity, and the stake resistance that described electric capacity is connected with comparer positive input terminal forms integrating circuit.
The utility model adopts positive feedback loop that zero crossings input signal can be avoided to shake the impact produced frequency measurement, and in positive feedback loop, add electric capacity formation integrating circuit, positive feedback can be made to lose efficacy before next zero crossing by controlling integration time constant, make to output signal during next zero crossing to there will not be phase delay, ensure that next zero crossing circuitry signal can accurate measurements in real time, thus ensured the stability of electronic load duty.
Accompanying drawing explanation
Fig. 1 is the utility model theory diagram;
Fig. 2 is filtering modulate circuit schematic diagram;
Fig. 3 is the utility model one specific embodiment schematic diagram.
Embodiment
Below in conjunction with the drawings and specific embodiments, technical solutions of the utility model are described in detail.
As shown in Figure 1, the utility model provides a kind of zero cross detection circuit being applied to electronic load, comprises filtering modulate circuit, comparer and output circuit.Ac input signal Vi is connected to comparer negative input end after filtering modulate circuit, and the output Vo of comparer is connected to the input end of output circuit, and the output Vout of output circuit is connected to comparer positive input terminal by positive feedback loop.Positive feedback loop adds the series circuit of electric capacity C1 and resistance R1, the stake resistance R2 that electric capacity C1 is connected with resistance R1 and comparer positive input terminal forms integrating circuit.Comparer positive input terminal is also connected with ground connection diode D1.
Output circuit is formed primarily of a triode, the output Vo of comparer is connected to transistor base through resistance R3, resistance R3 two ends shunt capacitance C2, contact resistance R4 between transistor base and collector, emitter connects stake resistance R5, emitter also connects the positive pole of diode D2, the negative pole connecting triode base stage of diode D2.The output Vout of output circuit takes from transistor emitter, provides zero passage detection signal to subsequent conditioning circuit.
Filtering modulate circuit as shown in Figure 2, can adopt existing universal circuit module, not repeat at this.
The utility model one specific embodiment is shown in Fig. 3.In order to reduce the impact of phase delay and reduction zero-crossing jitter, we select to add RC circuit in the positive feedback loop of comparer, after adding larger positive feedback, just can effectively avoid the shake of zero crossings to have an impact to frequency measurement, control 0.5 cycle that integration time constant is less than highest frequency point 450HZ, to ensure that next zero crossing circuitry signal can Real-Time Monitoring simultaneously.
In Fig. 3, diode D1, D2 in diode D16, D14 difference corresponding diagram 1, electric capacity C1, C2 in resistance R1 ~ R5 electric capacity C89, C88 difference corresponding diagram 1 in resistance R124, R126, R122, R119, R125 difference corresponding diagram 1.
LM393D is comparer, when 2 pin of LM393D occur rising edge and are greater than zero potential, its 1 pin exports-5V and has dragged down 3 pin current potentials by positive feedback, even if at this moment 2 pin inputs have small size disturbance also can not affect output signal, due to the existence of electric capacity C89, positive feedback can be controlled by integration time constant to lose efficacy after capacitor charging completes, now 2 pin inputs are also away from zero level phase place, will output be made to occur phase delay because of the existence of positive feedback when next zero crossing.The principle that the 2 pin input of LM393 drops to when being less than zero potential is the same.
Claims (4)
1. one kind is applied to the zero cross detection circuit of electronic load, comprise filtering modulate circuit, comparer and output circuit, input signal is connected to comparer negative input end through filtering modulate circuit, the output of comparer is connected to the input end of output circuit, and the output of output circuit is connected to comparer positive input terminal by positive feedback loop, it is characterized in that, described positive feedback loop is serially connected with electric capacity, and the stake resistance that described electric capacity is connected with comparer positive input terminal forms integrating circuit.
2. be applied to the zero cross detection circuit of electronic load as claimed in claim 1, it is characterized in that the positive input terminal of comparer is also connected with ground connection diode.
3. be applied to the zero cross detection circuit of electronic load as claimed in claim 1, it is characterized in that described output circuit comprises a triode, the output of described comparer is connected to transistor base through a resistance, and described resistor coupled in parallel one electric capacity, is connected in series a diode between transistor emitter and base stage.
4. be applied to the zero cross detection circuit of electronic load as claimed in claim 1, it is characterized in that the integration time constant of described integrating circuit is less than 0.5 cycle of input signal highest frequency point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520679202.3U CN204964613U (en) | 2015-09-06 | 2015-09-06 | Zero -cross detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520679202.3U CN204964613U (en) | 2015-09-06 | 2015-09-06 | Zero -cross detection circuit |
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| Publication Number | Publication Date |
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| CN204964613U true CN204964613U (en) | 2016-01-13 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201520679202.3U Active CN204964613U (en) | 2015-09-06 | 2015-09-06 | Zero -cross detection circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106093564A (en) * | 2016-07-27 | 2016-11-09 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN109917177A (en) * | 2019-04-12 | 2019-06-21 | 国网江苏省电力有限公司宿迁供电分公司 | A kind of jamproof zero cross detection circuit and detection method |
| CN110192113A (en) * | 2017-02-09 | 2019-08-30 | 理化工业株式会社 | Zero crossing detection device and zero passage detection method |
| CN112540219A (en) * | 2020-11-13 | 2021-03-23 | 珠海格力电器股份有限公司 | Zero-crossing detection circuit and control circuit |
| US11005465B1 (en) | 2020-01-13 | 2021-05-11 | Hamilton Sunstrand Corporation | Zero-cross circuit with low phase delay |
-
2015
- 2015-09-06 CN CN201520679202.3U patent/CN204964613U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106093564A (en) * | 2016-07-27 | 2016-11-09 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN106093564B (en) * | 2016-07-27 | 2019-04-02 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN110192113A (en) * | 2017-02-09 | 2019-08-30 | 理化工业株式会社 | Zero crossing detection device and zero passage detection method |
| CN110192113B (en) * | 2017-02-09 | 2021-03-12 | 理化工业株式会社 | Zero-crossing detection device and zero-crossing detection method |
| CN109917177A (en) * | 2019-04-12 | 2019-06-21 | 国网江苏省电力有限公司宿迁供电分公司 | A kind of jamproof zero cross detection circuit and detection method |
| US11005465B1 (en) | 2020-01-13 | 2021-05-11 | Hamilton Sunstrand Corporation | Zero-cross circuit with low phase delay |
| CN112540219A (en) * | 2020-11-13 | 2021-03-23 | 珠海格力电器股份有限公司 | Zero-crossing detection circuit and control circuit |
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