CN213843380U - Zero-crossing detection circuit - Google Patents
Zero-crossing detection circuit Download PDFInfo
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- CN213843380U CN213843380U CN202022615523.0U CN202022615523U CN213843380U CN 213843380 U CN213843380 U CN 213843380U CN 202022615523 U CN202022615523 U CN 202022615523U CN 213843380 U CN213843380 U CN 213843380U
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Abstract
The utility model relates to an alternating current zero-crossing detection field discloses a zero-crossing detection circuit, including interface L, N, the mirror current source, first steady voltage unit, second steady voltage unit, control switch and load, the mirror current source includes triode Q1 and triode Q2, interface L is connected with the input of first steady voltage unit and the output electricity of second steady voltage end member respectively, the output of first steady voltage unit is connected with control switch's input electricity, control switch's control end is connected with interface N electricity, the input of second steady voltage unit is connected with triode Q1's base respectively, triode Q2's base and triode Q2's collecting electrode electricity are connected, triode Q1's projecting pole and triode Q2's projecting pole are connected with interface N electricity respectively, triode Q1's collecting electrode and control switch's output pass through load ground connection, the utility model discloses simple structure, through detecting the voltage on the load just can realize the zero-crossing detection of alternating current, can be integrated with the relevant control function chip.
Description
Technical Field
The utility model relates to an alternating current zero cross detection field, concretely relates to zero cross detection circuit.
Background
In the control of the ac motor, a zero-crossing detection circuit is usually used to detect a zero point of the ac power input to the ac motor. However, most of the existing zero-crossing detection circuits firstly reduce voltage by a transformer and then process the voltage signals after voltage reduction by a diode, an optocoupler and a triode, and the existing zero-crossing detection circuits are complex in structure and difficult to integrate with a control function chip.
SUMMERY OF THE UTILITY MODEL
In view of the deficiency of the background art, the utility model provides a zero cross detection circuit, the technical problem that solve is that current zero cross detection circuit structure is complicated, very can be in the same place with the control function chip is integrated.
For solving the technical problem, the utility model provides a following technical scheme: the utility model provides a zero cross detection circuit, including interface L, N, the mirror current source, first voltage stabilization unit, the second voltage stabilization unit, control switch and load, the mirror current source includes triode Q1 and triode Q2, interface L is connected with the input of first voltage stabilization unit and the output electricity of second voltage stabilization end element respectively, the output of first voltage stabilization unit is connected with control switch's input electricity, control switch's control end is connected with interface N electricity, the input of second voltage stabilization unit respectively with the base of triode Q1, the base of triode Q2 and the collecting electrode electricity of triode Q2, the projecting pole of triode Q1 and the projecting pole of triode Q2 are connected with interface N electricity respectively, the collecting electrode of triode Q1 and the output of control switch are connected with load one end electricity respectively, the load other end ground connection.
As a further technical solution, the transistor Q1 and the transistor Q2 are both PNP transistors.
As a further technical scheme, the control switch is a triode Q3.
Furthermore, the control switch is a PNP type triode.
The input end of the first voltage stabilizing unit and the output end of the second voltage stabilizing terminal element are electrically connected with the interface L through a current limiting resistor R2.
As a further technical solution, the first voltage regulation unit adopts a voltage regulation diode Z1, and the second voltage regulation unit adopts a voltage regulation diode Z2.
As a further technical solution, the cathode of the zener diode Z1 and the anode of the zener diode Z2 are electrically connected to the interface L through the current limiting resistor R2, respectively.
When first voltage regulation unit and second steady voltage were singly all adopted zener diode, triode Q1, triode Q2 and control switch were when PNP type triode, the utility model discloses a work flow as follows: firstly, the regulated voltage of a voltage regulator diode is 5.8V, when the commercial power is in a negative half cycle, the voltage of an interface L is lower than that of an interface N, when the voltage difference between the interface N and the interface L is more than 6.5V, a triode Q2 and a voltage regulator diode Z2 are conducted, as a triode Q2 and a triode Q1 form a mirror current source, Q1 is also conducted, the collector current of a triode Q1 generates voltage on a load, and the voltage is a detection signal; when the commercial power is in the positive half cycle, the voltage of the interface L is higher than that of the interface N, when the difference between the voltages of the interface L and the interface N is higher than 6.5V, the voltage regulator tube Z1 is conducted with the control switch, the current flowing into the control switch generates voltage on the load, and the voltage is a detection signal; when the commercial power is at a zero crossing point and the voltage difference between the voltage of the interface L and the voltage of the interface N is less than 6.5V, the voltage regulator tube Z2, the triode Q2 and the triode Q1 are not conducted, the voltage regulator tube Z2 and the control switch are also not conducted, no current exists on the load, and the voltage of the ungrounded end of the load is a low-level signal of 0V.
Compared with the prior art, the utility model beneficial effect who has is: the utility model discloses a steady voltage of stabilivolt and the conduction pressure drop of triode decide zero cross detection voltage threshold, when the absolute value of alternating current at the voltage of positive and negative half cycle is higher than threshold voltage, the one end that the load is ungrounded has the voltage signal output of high level, when the absolute value of alternating current at the voltage of positive and negative half cycle is less than threshold voltage, the voltage of the one end that the load is ungrounded is 0V's low level signal, with this realization zero cross detection, need not pass through the transformer, the voltage conversion of alternating current is realized to opto-coupler etc., the structure of zero cross detection circuit has been simplified, in addition because simple structure only need leave alternating current interface and load interface when practical application can, can be in the same place with relevant control function chip integration.
Drawings
The utility model discloses there is following figure:
fig. 1 is a circuit diagram of a zero-cross detection circuit in an embodiment;
fig. 2 is a waveform diagram of the zero-cross detection circuit in the embodiment when applied.
In the figure; 1. the device comprises a first voltage stabilizing unit, a second voltage stabilizing unit, a control switch, a mirror current source, a load and a first voltage stabilizing unit 2, a second voltage stabilizing unit 3, a control switch 4.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.
As shown in fig. 1, a zero crossing detection circuit includes an interface L, N, a mirror current source 4, a first voltage stabilization unit 1, the second voltage stabilizing unit 2, the control switch 3 and the load 5, the mirror current source 4 includes a triode Q1 and a triode Q2, the interface L is electrically connected with the input end of the first voltage stabilizing unit 1 and the output end of the second voltage stabilizing terminal element 2, the output end of the first voltage stabilizing unit 1 is electrically connected with the input end of the control switch 3, the control end of the control switch 3 is electrically connected with the interface N, the input end of the second voltage stabilizing unit 2 is electrically connected with the base electrode of the triode Q1, the base electrode of the triode Q2 and the collector electrode of the triode Q2, the emitter electrode of the triode Q1 and the emitter electrode of the triode Q2 are electrically connected with the interface N, the collector electrode of the triode Q1 and the output end of the control switch 3 are electrically connected with one end of the load 5, and the other end of the load 5 is grounded.
In this embodiment, the control switch 3 employs a transistor Q3, the first voltage regulation unit 1 employs a zener diode Z1, the zener diode Z1 regulates the voltage of the interface L, the second voltage regulation unit 2 employs a zener diode Z2, the zener diode Z2 regulates the voltage of the interface N, and the regulated voltages of the zener diode Z1 and the zener diode Z2 are both 5.8V.
In this embodiment, the transistor Q1, the transistor Q2, and the transistor Q3 are all PNP transistors.
In order to limit the current when the zero-cross detection circuit operates, the cathode of the zener diode Z1 and the anode of the zener diode Z2 are electrically connected with one end of a current limiting resistor R2, and the other end of the current limiting resistor R2 is electrically connected with the interface L.
In this embodiment, the voltage detection threshold of the zero-cross detection circuit is determined by the regulated voltage of the regulator diode Z1 and the conduction voltage drop of the transistor Q1, and since the conduction voltage drop of the transistor is mostly 0.7V, the voltage at the VCC terminal in fig. 1 is 6.5V.
According to fig. 1, the working principle of the present invention is as follows: when the commercial power is in a negative half cycle, the voltage of the interface L is lower than that of the interface N, when the difference between the voltages of the interface N and the interface L is greater than 6.5V, the triode Q2 and the zener diode Z2 are conducted, the triode Q2 and the triode Q1 form a mirror current source, so that the Q1 is also conducted, the collector current of the triode Q1 generates a voltage on the resistor R1, the voltage is a high-level detection signal, and when the voltage is actually used, the detection signal can be obtained by detecting the voltage of the OUT end; when the commercial power is in the positive half cycle, the voltage of the interface L is higher than that of the interface N, when the difference between the voltages of the interface L and the interface N is higher than 6.5V, the voltage regulator tube Z1 is conducted with the triode Q3, the current flowing into the triode Q3 generates voltage on the resistor R1, and the voltage is a high-level detection signal; when the commercial power is at a zero crossing point and the voltage difference between the voltage of the interface L and the voltage of the interface N is less than 6.5V, the voltage regulator tube Z2, the triode Q2 and the triode Q1 are not conducted, the voltage regulator tube Z2 and the triode Q3 are also not conducted, no current exists on the resistor R1, and the OUT end is a low-level signal of 0V.
The utility model discloses oscillogram during operation can refer to fig. 2, and the voltage signal of OUT end is periodic high low level signal, and its frequency is the same with the frequency of commercial power, and when the voltage signal of OUT end was the low level, the voltage in the twinkling of an eye of commercial power was near zero.
To sum up, the utility model discloses a regulator tube Z1's steady voltage and triode Q3's conduction pressure drop determine zero cross detection's voltage threshold, when the absolute value of alternating current at positive and negative half cycle's voltage is higher than threshold voltage, the one end that the load is ungrounded has the voltage signal output of high level, when the absolute value of alternating current at positive and negative half cycle's voltage is less than threshold voltage, the voltage of the one end that the load is ungrounded is 0V's low level signal, with this realize zero cross detection, need not pass through the transformer, the voltage conversion of alternating current is realized to opto-coupler etc., the structure of zero cross detection circuit has been simplified, in addition because simple structure only need leave alternating current interface and load interface when practical application can, can be in the same place with relevant control function chip integration.
In light of the above, the present invention is not limited to the above embodiments, and various changes and modifications can be made by the worker without departing from the scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (7)
1. A zero-crossing detection circuit, characterized by: including interface L, N, mirror current source, first steady voltage unit, second steady voltage unit, control switch and load, the mirror current source includes triode Q1 and triode Q2, interface L is connected with the input of first steady voltage unit and the output electricity of second steady voltage end element respectively, the output of first steady voltage unit is connected with control switch's input electricity, control switch's control end is connected with interface N electricity, the input of second steady voltage unit is connected with triode Q1's base, triode Q2's base and triode Q2's collecting electrode electricity respectively, triode Q1's projecting pole and triode Q2's projecting pole are connected with interface N electricity respectively, triode Q1's collecting electrode and control switch's output are connected with load one end electricity respectively, and the load other end ground connection.
2. A zero-crossing detection circuit as claimed in claim 1, wherein: and the triode Q1 and the triode Q2 are PNP type triodes.
3. A zero-crossing detection circuit as claimed in claim 1, wherein: the control switch is a triode Q3.
4. A zero-crossing detection circuit as claimed in claim 3, wherein: the control switch is a PNP type triode.
5. A zero-crossing detection circuit as claimed in claim 1, wherein: the first voltage stabilizing unit adopts a voltage stabilizing diode Z1.
6. A zero-crossing detection circuit as claimed in claim 1, wherein: the second voltage stabilizing unit adopts a voltage stabilizing diode Z2.
7. A zero-crossing detection circuit as claimed in claim 1, wherein: the input end of the first voltage stabilizing unit and the output end of the second voltage stabilizing terminal element are electrically connected with the interface L through a current limiting resistor R2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022615523.0U CN213843380U (en) | 2020-11-12 | 2020-11-12 | Zero-crossing detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022615523.0U CN213843380U (en) | 2020-11-12 | 2020-11-12 | Zero-crossing detection circuit |
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| CN213843380U true CN213843380U (en) | 2021-07-30 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115575700A (en) * | 2022-11-09 | 2023-01-06 | 上海芯龙半导体技术股份有限公司 | Zero-crossing detection circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115575700A (en) * | 2022-11-09 | 2023-01-06 | 上海芯龙半导体技术股份有限公司 | Zero-crossing detection circuit |
| CN115575700B (en) * | 2022-11-09 | 2023-03-10 | 上海芯龙半导体技术股份有限公司 | Zero-crossing detection circuit |
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