CN212364414U - Zero-crossing detection circuit and system thereof - Google Patents
Zero-crossing detection circuit and system thereof Download PDFInfo
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- CN212364414U CN212364414U CN202020539982.2U CN202020539982U CN212364414U CN 212364414 U CN212364414 U CN 212364414U CN 202020539982 U CN202020539982 U CN 202020539982U CN 212364414 U CN212364414 U CN 212364414U
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Abstract
The utility model discloses a zero cross detection circuit and system thereof, in zero cross detection circuit, charge and discharge circuit's first end is connected with alternating current power supply's live wire, the second end is connected with one-way conduction circuit's first end, switch circuit's first end and opto-coupler isolation circuit's first input, one-way conduction circuit's second end is connected with alternating current power supply's zero line and switch circuit's second end, switch circuit's third end is connected with opto-coupler isolation circuit's second input, opto-coupler isolation circuit's output and controller are connected. In the process that the alternating current power supply is from the wave crest to the wave trough, the switching circuit works in a cut-off state, so that the optical coupling isolation circuit is disconnected, and a high-level signal is output; in the process that the alternating current power supply is from a wave trough to a wave crest, the one-way conduction circuit is in a cut-off state, the switching circuit works in a conduction state, the charge-discharge circuit supplies power to the optical coupling isolation circuit, the optical coupling isolation circuit is driven to be conducted, and a low level signal is output. By the above mode, power consumption can be reduced.
Description
Technical Field
The embodiment of the utility model provides a relate to circuit protection technical field, especially relate to a zero cross detection circuit and system thereof.
Background
In household electrical products, an isolated power supply is generally used to ensure the safety of the household electrical products, and at this time, in order to better control the load, a zero-crossing signal of the power supply is often required to be detected.
At present, when a zero-crossing signal of a power supply is detected, a used zero-crossing detection circuit is mostly connected with the power supply through energy consumption elements such as resistors, and high voltage of the power supply acts on the energy consumption elements, so that large power consumption is generated, and energy waste is caused.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the utility model discloses a technical scheme be: provided is a zero-cross detection circuit including: the charging and discharging circuit, the unidirectional conducting circuit, the switch circuit and the optical coupling isolation circuit;
the first end of the charge-discharge circuit is used for being connected with a live wire of an alternating current power supply, the second end of the charge-discharge circuit is connected with the first end of the unidirectional conduction circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit, the second end of the unidirectional conduction circuit is used for being connected with a zero line of the alternating current power supply and the second end of the switch circuit, the third end of the switch circuit is connected with the second input end of the optical coupling isolation circuit, and the output end of the optical coupling isolation circuit is used for being connected with a controller;
in the process that the alternating current power supply changes from a wave crest to a wave trough, the switch circuit works in a cut-off state, so that the optical coupling isolation circuit is disconnected, and the optical coupling isolation circuit outputs a high-level signal;
in the process that the alternating current power supply changes from a wave trough to a wave crest, the one-way conduction circuit is in a cut-off state, the switching circuit works in a conduction state, the charge and discharge circuit supplies power to the optical coupling isolation circuit to drive the optical coupling isolation circuit to be conducted, and the optical coupling isolation circuit outputs a low level signal.
Optionally, the charging and discharging circuit includes: a first capacitor;
the first end of the first capacitor is used for being connected with a live wire of the alternating current power supply, and the second end of the first capacitor is connected with the first end of the one-way conduction circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit.
Optionally, the unidirectional conducting circuit comprises: a first diode;
the negative pole of the first diode is connected with the second end of the charge-discharge circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit, and the positive pole of the first diode is used for being connected with the zero line of the alternating current power supply and the second end of the switch circuit.
Optionally, the switching circuit comprises: an NPN triode;
the base electrode of the NPN triode is connected with the second end of the charge-discharge circuit, the first end of the unidirectional conduction circuit and the first input end of the optical coupling isolation circuit;
an emitting electrode of the NPN triode is used for being connected with a zero line of the alternating current power supply and a second end of the one-way conduction circuit;
and the collector of the NPN triode is connected with the second input end of the optical coupling isolation circuit.
Optionally, the optical coupling isolation circuit comprises: the optical coupler, the sampling circuit and the first power supply;
the anode of a light emitting diode of the optocoupler is connected with the second end of the charge-discharge circuit, the first end of the unidirectional conduction circuit and the first end of the switch circuit;
the negative electrode of a light emitting diode of the optocoupler is connected with the third end of the switch circuit;
a collector electrode of a phototriode of the optocoupler is connected with an input end of the sampling circuit, a power supply end of the sampling circuit is connected with the first power supply, and an output end of the sampling circuit is used for being connected with a controller;
and an emitting electrode of a phototriode of the optocoupler is grounded.
Optionally, the sampling circuit comprises: a first resistor, a second resistor and a second capacitor;
the first end of first resistance with first power is connected, the second end of first resistance with the collecting electrode of the phototriode of opto-coupler and the first end of second resistance is connected, the second end of second resistance be used for with the controller with the first end of second electric capacity is connected, the second end ground connection of second electric capacity.
Optionally, the zero-crossing detection circuit further includes: a rectification circuit and an electrolytic capacitor;
the first end of the rectifying circuit is connected with the second end of the charging and discharging circuit, the first end of the unidirectional conduction circuit and the first end of the switch circuit, the second end of the rectifying circuit is connected with the first input end of the optical coupling isolation circuit and the anode of the electrolytic capacitor, and the cathode of the electrolytic capacitor is connected with the second end of the unidirectional conduction circuit and the second end of the switch circuit.
Optionally, the rectifier circuit is a half-bridge rectifier circuit.
Optionally, the zero-crossing detection circuit further includes: a protection circuit;
the first end of the protection circuit is connected with the second end of the charge and discharge circuit, the first end of the one-way conduction circuit and the first end of the switch circuit, and the second end of the protection circuit is connected with the first input end of the optical coupling isolation circuit.
For solving the technical problem, the utility model discloses a another technical scheme is: there is provided a zero-crossing detection system comprising: the alternating current power supply, the controller and the zero-crossing detection circuit;
the output end of the alternating current power supply is connected with the input end of the zero-crossing detection circuit, and the output end of the zero-crossing detection circuit is connected with the controller;
the zero-crossing detection circuit is used for collecting a zero-crossing signal of the alternating current power supply and sending the zero-crossing information to the controller, so that the controller determines the zero-crossing point of the alternating current power supply according to the zero-crossing signal.
The embodiment of the utility model provides a beneficial effect is: be different from prior art's condition, the embodiment of the utility model provides a zero cross detection circuit and system thereof, this zero cross detection circuit includes charge-discharge circuit, one-way conduction circuit, switch circuit and opto-coupler isolating circuit, charge-discharge circuit's first end is used for being connected with alternating current power supply's live wire, charge-discharge circuit's second end and one-way conduction circuit's first end, switch circuit's first end and opto-coupler isolating circuit's first input are connected, one-way conduction circuit's second end is used for holding with alternating current power supply's zero line and switch circuit's second and is connected, switch circuit's third end is connected with opto-coupler isolating circuit's second input, opto-coupler isolating circuit's output then is used for being connected with the controller. The zero-crossing detection circuit is connected with the alternating current power supply through the charge and discharge circuit, and therefore when the alternating current power supply flows through the charge and discharge circuit, the charge and discharge circuit can reduce the voltage of the alternating current power supply in a mode of storing electric energy, energy loss is prevented, power consumption is reduced, and reasonable utilization of resources is achieved.
Drawings
One or more embodiments are illustrated in drawings corresponding to, and not limiting to, the embodiments, in which elements having the same reference number designation may be represented as similar elements, unless specifically noted, the drawings in the figures are not to scale.
Fig. 1 is a schematic connection diagram of a zero-crossing detection system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a zero-crossing detection system according to an embodiment of the present invention;
FIG. 3 is a waveform diagram of an AC power source and a zero crossing signal;
fig. 4 is a schematic structural diagram of a zero-crossing detection circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a zero-crossing detection circuit according to another embodiment of the present invention;
fig. 6 is a schematic structural diagram of a zero-crossing detection circuit according to another embodiment of the present invention;
fig. 7 is a schematic structural diagram of a zero-crossing detection circuit according to another embodiment of the present invention;
fig. 8 is a schematic structural diagram of a zero-crossing detection circuit according to another embodiment of the present invention.
Detailed Description
In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the accompanying drawings and specific embodiments. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for descriptive purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Please refer to fig. 1 and fig. 2, which are schematic structural diagrams of a zero-crossing detecting system according to an embodiment of the present invention, the zero-crossing detecting system includes: the alternating current power supply 100, the controller 200 and the zero-crossing detection circuit 300, wherein the output end of the alternating current power supply 100 is connected with the input end of the zero-crossing detection circuit 300, the output end of the zero-crossing detection circuit 300 is connected with the controller 200, the zero-crossing detection circuit 300 is used for collecting the zero-crossing signal of the alternating current power supply 100 and sending the collected zero-crossing signal to the controller 200, and the controller 200 determines the zero-crossing point of the alternating current power supply 100 according to the zero-crossing signal sent by the zero-crossing detection circuit 300.
The ac power supply 100 is configured to output a sinusoidally varying ac power. Preferably, in the embodiment of the present invention, the ac power source 100 is a commercial power.
The controller 200 may be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or a single chip, etc. Preferably, in the embodiment of the present invention, the controller 200 is a single chip microcomputer.
The zero-crossing detection circuit 300 includes: charge-discharge circuit 310, unidirectional circuit 320, switch circuit 330 and opto-coupler isolation circuit 340, the first end of charge-discharge circuit 310 is connected with alternating current power supply 100's live wire, the second end of charge-discharge circuit 310 and unidirectional circuit 320's first end, switch circuit 330's first end and opto-coupler isolation circuit 340's first input end are connected, unidirectional circuit 320's second end is connected with alternating current power supply 100's zero line and switch circuit 330's second end, switch circuit 330's third end is connected with opto-coupler isolation circuit 340's second input end, opto-coupler isolation circuit 340's output then is connected with controller 200.
In the zero-crossing detection circuit 300, when the alternating current power supply 100 changes from a wave crest to a wave trough, the switching circuit 330 works in a cut-off state, so that the optical coupling isolation circuit 340 is switched off, and the optical coupling isolation circuit 340 outputs a high-level signal; when the alternating current power supply 100 changes from a wave trough to a wave crest, the unidirectional conducting circuit 320 is in a cut-off state, the switching circuit 330 works in a conducting state, the charging and discharging circuit 310 supplies power to the optical coupling isolation circuit 340, the optical coupling isolation circuit 340 is driven to be conducted, and the optical coupling isolation circuit 340 outputs a low-level signal.
The unidirectional conducting circuit 320 is in a cut-off state when the charging and discharging circuit 310 supplies power; the switching circuit 330 operates in a conducting state when the input voltage at the first terminal is greater than the input voltage at the second terminal; the optical coupling isolation circuit 340 is turned on when the switching circuit 330 is in the on state and the charging and discharging circuit 310 supplies power.
The working principle is as follows: when the alternating current power supply 100 changes from zero to a peak, the alternating current power supply 100 is positively input (the live wire is the positive pole, and the zero line is the negative pole) to the zero-cross detection circuit 300, at this time, because the voltage of the alternating current power supply 100 rises, the charge and discharge circuit 310 is in a positive charging state, the charge and discharge circuit 310 can supply power, so that the one-way conduction circuit 320 is in a cut-off state, and the voltage output by the charge and discharge circuit 310 is greater than the zero line voltage, so that the input voltage of the first end of the switch circuit 330 is greater than the input voltage of the second end, therefore, the switch circuit 330 works in a conduction state, and the optocoupler isolation circuit 340 is conducted under the condition that the switch circuit 330 works;
when the alternating current power supply 100 changes from a wave crest to a zero point, the alternating current power supply 100 inputs a zero-crossing detection circuit 300 in a forward direction (a live wire is a positive pole, and a zero line is a negative pole), at this time, because the voltage of the alternating current power supply 100 is reduced, the charge and discharge circuit 310 is in a reverse discharge state, the charge and discharge circuit 310 cannot supply power, the switch circuit 330 works in a cut-off state, and under the condition that the switch circuit 330 works in the cut-off state, the optical coupling isolation circuit 340 is disconnected;
when the alternating current power supply 100 changes from zero to a wave trough, the alternating current power supply 100 reversely inputs (the live wire is a negative electrode, and the zero line is a positive electrode) the zero-crossing detection circuit 300, at this time, the one-way conduction circuit 320 is in a conduction state, and as the voltage of the alternating current power supply 100 rises, the alternating current power supply 100 reversely charges the charge and discharge circuit 310 through the one-way conduction circuit 320, the charge and discharge circuit 310 cannot supply power, the first end of the switch circuit 330 is connected to the zero line, so that the input voltage of the first end of the switch circuit 330 is the same as the input voltage of the second end, the switch circuit 330 works in a cut-off state, and the optical coupling isolation circuit 340 is disconnected under the condition that;
when the ac power supply 100 changes from the trough to the zero point, the ac power supply 100 reversely inputs (the live wire is the negative electrode, and the zero line is the positive electrode) the zero-cross detection circuit 300, at this time, because the voltage of the ac power supply 100 drops, the charging and discharging circuit 310 is in the forward discharging state, the charging and discharging circuit 310 can supply power, so that the unidirectional conducting circuit 320 is in the cut-off state, and the voltage output by the charging and discharging circuit 310 is greater than the zero line voltage, so that the input voltage of the first end of the switching circuit 330 is greater than the input voltage of the second end, therefore, the switching circuit 330 works in the conducting state, and under the condition that the switching circuit 330 works in the conducting state and the charging and discharging circuit 310 supplies power.
Go toStep by step, since the zero-cross detection circuit 300 outputs a high level signal when the ac power supply 100 changes from a peak to a valley, and outputs a low level signal when the ac power supply 100 changes from a valley to a peak, the zero-cross signal acquired by the zero-cross detection circuit 300 is a square wave signal with a high level and a low level, and the phase difference between the zero-cross signal and the ac power output by the ac power supply 100 is a quarter cycle (as shown in fig. 3), based on which, when the controller 200 determines the zero-cross point of the ac power supply 100 according to the zero-cross signal sent by the zero-cross detection circuit 300, the rising edge time or the falling edge time of the zero-cross signal is determined, and then the zero-cross point of the ac power supply 100 can be determined according to the quarter cycle and the rising edge time of the zero-cross signal, or according to. For example, referring to FIG. 3, if the rising edge of the zero-crossing signal is T1 and the period is T, the zero-crossing point is
Further, referring to fig. 4, in some embodiments, the charging and discharging circuit 310 includes: a first capacitor C1.
A first end of the first capacitor C1 is connected to the live line L of the ac power source 100;
a second terminal of the first capacitor C1 is connected to the first terminal of the unidirectional conducting circuit 320, the first terminal of the switch circuit 330, and the first input terminal of the optical coupler isolation circuit 340.
The unidirectional conducting circuit 320 includes: the first diode D1.
The cathode of the first diode D1 is connected to the second end of the first capacitor C1, the first end of the switch circuit 330 and the first input end of the opto-isolator circuit 340;
the anode of the first diode D1 is connected to the neutral line N of the ac power supply 100 and to the second terminal of the switching circuit 330.
The switching circuit 330 includes: an NPN transistor Q1.
The base of the NPN triode Q1 is connected to the second end of the first capacitor C1, the negative electrode of the first diode D1, and the first input end of the opto-coupler isolation circuit 340;
an emitting electrode of the NPN triode Q1 is connected with a zero line N of the alternating current power supply 100 and the positive electrode of the first diode D1;
the collector of the NPN transistor Q1 is connected to the second input of the opto-isolator circuit 340.
The optical coupler isolation circuit 340 includes: an opto-coupler U1, a sampling circuit 341, and a first power source 342.
The optical coupler U1 comprises a light emitting element and a light receiving element. In the embodiment of the present invention, the optocoupler U1 model is LTV8165, the light emitting element is a light emitting diode, and the light receiving element is a phototriode.
At this time, the anode of the light emitting diode of the optocoupler U1 is connected with the second end of the first capacitor C1, the cathode of the first diode D1 and the base of the NPN triode Q1;
the negative electrode of a light emitting diode of the optocoupler U1 is connected with the collector of an NPN triode Q1;
a collector of a phototriode of the optocoupler U1 is connected with an input end of the sampling circuit 341, a power supply end of the sampling circuit 341 is connected with the first power supply 342, and an output end of the sampling circuit 341 is connected with the controller 200;
the emitter of the phototriode of the optocoupler U1 is grounded.
In the optical coupler isolation circuit 340, when the optical coupler U1 is turned on, the input end of the sampling circuit 341 is grounded, and the sampling circuit 341 outputs a low level signal; when the optocoupler U1 is turned off, the first power source 342 is input to the sampling circuit 341, and the sampling circuit 341 outputs a high level signal.
Based on this, it can be understood that in the zero-crossing detection circuit 300 shown in fig. 4, when the ac power supply 100 changes from zero to peak, the ac power supply 100 is input to the zero-crossing detection circuit 300 in the forward direction (the live line is the positive electrode, and the zero line is the negative electrode), at this time, as the voltage of the ac power supply 100 rises, the first capacitor C1 is in the forward charging state, the first capacitor C1 can supply power, so that the voltage of the negative electrode of the first diode D1 is greater than the voltage of the positive electrode, and the forward conducting condition of the first diode D1 is not satisfied, the first diode D1 is in the cut-off state, at this time, the base of the NPN transistor NPN Q1 is connected to the first capacitor C1, the emitter of the NPN transistor Q1 is connected to the zero line, and the voltage output by the first capacitor C1 is greater than the zero line voltage, so that the base voltage of the NPN transistor Q1 is greater than the emitter voltage, the conducting condition of the NPN transistor, under the condition that the NPN triode Q1 works in a conducting state and the first capacitor C1 supplies power, a light emitting diode of the optocoupler U1 is conducted, so that a photoelectric triode of the optocoupler U1 is conducted, the input end of the sampling circuit 341 is grounded, and the sampling circuit 341 outputs a low-level signal;
when the alternating current power supply 100 changes from a wave crest to a zero point, the alternating current power supply 100 is input in a forward direction (a live wire is an anode, and a zero line is a cathode) to the zero-crossing detection circuit 300, at this time, because the voltage of the alternating current power supply 100 drops, the first capacitor C1 is in a reverse discharge state, the first capacitor C1 cannot supply power, so that no voltage is input to the base of the NPN triode Q1, the conduction condition of the NPN triode Q1 is not satisfied, the NPN triode Q1 works in a cut-off state, and under the condition that the NPN triode Q1 works in the cut-off state, the light emitting diode of the optocoupler U1 is cut off, so that the phototriode of the optocoupler U1 is cut off, the first power supply 342 is input to the;
when the alternating current power supply 100 changes from the zero point to the wave trough, the alternating current power supply 100 reversely inputs the zero-crossing detection circuit 300 (the live wire is the negative electrode, and the zero wire is the positive electrode), at this time, as the voltage of the alternating current power supply 100 rises, the positive electrode voltage of the first diode D1 is greater than the negative electrode voltage, the forward conduction condition of the first diode D1 is met, and the first diode D1 is in a conduction state; after the first diode D1 is in an on state, the ac power supply 100 can reversely charge the first capacitor C1 through the first diode D1, at this time, the first capacitor C1 cannot supply power, the base of the NPN triode Q1 is connected to the zero line through the first diode D1, so that the base voltage of the NPN triode Q1 is the same as the emitter voltage, and the on condition of the NPN triode Q1 is not satisfied, the NPN triode Q1 operates in an off state, and when the NPN triode Q1 operates in the off state, the light emitting diode of the optocoupler U1 is turned off, so that the phototransistor of the optocoupler U1 is turned off, the first power supply 342 inputs the sampling circuit 341, and the sampling circuit 341 outputs a high level signal;
when the ac power supply 100 changes from the trough to the zero point, the ac power supply 100 reversely inputs (the live line is the negative electrode, and the zero line is the positive electrode) the zero cross detection circuit 300, at this time, because the voltage of the ac power supply 100 drops, the first capacitor C1 is in the forward discharge state, the first capacitor C1 can supply power, so that the negative electrode voltage of the first diode D1 is greater than the positive electrode voltage, the forward conduction condition of the first diode D1 is not satisfied, the first diode D1 is in the cut-off state, at this time, the base of the NPN triode Q1 is connected with the first capacitor C1, the emitter of the NPN triode Q1 is connected with the zero line, and as the voltage of the ac power supply 100 drops, the base voltage of the NPN triode Q1 is greater than the emitter voltage 86525, the conduction condition of the NPN triode Q1 is satisfied, the NPN triode Q387 operates in the conduction state, and under the condition that the NPN Q1 operates in the conduction state, the light emitting diode of the optocoupler U1 is conducted, so that the phototriode of the optocoupler U1 is conducted, the input end of the sampling circuit 341 is grounded, and the sampling circuit 341 outputs a low-level signal.
Further, referring to fig. 5, in some embodiments, the sampling circuit 341 specifically includes: a first resistor R1, a second resistor R2 and a second capacitor C2.
A first end of the first resistor R1 is connected to the first power source 342, and a second end of the first resistor R1 is connected to a collector of a phototransistor of the optocoupler U1 and a first end of the second resistor R2;
a second end of the second resistor R2 is connected to the controller 200 and a first end of the second capacitor C2;
the second terminal of the second capacitor C2 is connected to ground.
When the optocoupler U1 is turned on, the first end of the second resistor R2 is grounded, so that the second end of the second resistor R2 outputs a low level to the controller 200; when the optocoupler U1 is turned off, the first resistor R1 and the second resistor R2 divide the voltage of the first power source 342, and at this time, the second end of the second resistor R2 outputs a high level to the controller 200.
Further, referring to fig. 6, in some embodiments, in order to output a stable direct current to the optocoupler isolation circuit 340, the zero-crossing detection circuit 300 further includes: a rectifying circuit 350 and an electrolytic capacitor C3.
The first end of the rectifying circuit 350 is connected to the second end of the charging and discharging circuit 310, the first end of the unidirectional conducting circuit 320 and the first end of the switching circuit 330, the second end of the rectifying circuit 350 is connected to the first input end of the optical coupling isolation circuit 340 and the positive electrode of the electrolytic capacitor C3, and the negative electrode of the electrolytic capacitor C3 is connected to the second end of the unidirectional conducting circuit 320 and the second end of the switching circuit 330.
The rectifying circuit 350 is configured to rectify the alternating current output by the charging and discharging circuit 310 to obtain direct current; the electrolytic capacitor C3 is charged and discharged by the dc power output from the rectifying circuit 350 to output a stable dc power to the opto-isolator circuit 340.
Specifically, a first end of the rectifying circuit 350 is connected to a second end of the first capacitor C1, a first end of the first diode D1, and a base of the NPN transistor Q1, a second end of the rectifying circuit 350 is connected to an anode of the light emitting diode of the optocoupler U1 and an anode of the electrolytic capacitor C3, and a cathode of the electrolytic capacitor C2 is connected to an anode of the first diode D1 and an emitter of the NPN transistor Q1.
In the embodiment of the present invention, this rectifier circuit 350 is a half-bridge rectifier circuit, and it specifically includes: and a second diode D2, an anode of the second diode D2 being connected to the second end of the first capacitor C1, the first end of the first diode D1, and the base of the NPN transistor Q1, and a cathode of the second diode D2 being connected to an anode of the light emitting diode of the optocoupler U1 and an anode of the electrolytic capacitor C3.
Of course, in some alternative embodiments, the rectifying circuit 350 may also be a full bridge rectifying circuit.
Further, referring to fig. 7, in some embodiments, the zero crossing detection circuit 300 further includes: a protection circuit 360.
The first end of the protection circuit 360 is connected to the second end of the rectifying circuit 350 and the anode of the electrolytic capacitor C3, and the second end of the protection circuit 360 is connected to the first input end of the optical coupler isolation circuit 340.
The protection circuit 360 is used for protecting the optical coupling isolation circuit 340 to prevent the current input to the optical coupling isolation circuit 340 from being too large.
Specifically, a first end of the protection circuit 360 is connected to a cathode of the second diode D2 and an anode of the electrolytic capacitor C3, and a second end of the protection circuit 360 is connected to an anode of the light emitting diode of the optocoupler U1.
In the embodiment of the present invention, the protection circuit 360 specifically includes: and a first end of the third resistor R3 is connected with a cathode of the second diode D2 and an anode of the electrolytic capacitor C3, and a second end of the third resistor R3 is connected with an anode of a light emitting diode of the optocoupler U1.
Referring to fig. 8, in some alternative embodiments, the protection circuit 360 may be directly disposed without the rectifying circuit 350 and the electrolytic capacitor C3, at this time, the first terminal of the protection circuit 360 is connected to the second terminal of the charging and discharging circuit 310, the first terminal of the unidirectional conducting circuit 320, and the first terminal of the switching circuit 330, and the second terminal of the protection circuit 360 is connected to the first input terminal of the optical coupling isolation circuit 340.
Specifically, a first terminal of the protection circuit 360 is connected to the second terminal of the first capacitor C1, the negative electrode of the first diode D1, and the base of the NPN transistor Q1, and a second terminal of the protection circuit 360 is connected to the positive electrode of the light emitting diode of the optocoupler U1.
The embodiment of the utility model provides an in, zero passage detection circuit passes through charge-discharge circuit and is connected with alternating current power supply, can prevent energy loss at alternating current power supply storage electric energy when flowing through, reduces the consumption, realizes the rational utilization of resource.
It should be noted that the preferred embodiments of the present invention are described in the specification and the drawings, but the present invention can be realized in many different forms, and is not limited to the embodiments described in the specification, and these embodiments are not provided as additional limitations to the present invention, and are provided for the purpose of making the understanding of the disclosure of the present invention more thorough and complete. Moreover, the above technical features are combined with each other to form various embodiments which are not listed above, and all the embodiments are regarded as the scope of the present invention; further, modifications and variations will occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A zero-crossing detection circuit, comprising: the charging and discharging circuit, the unidirectional conducting circuit, the switch circuit and the optical coupling isolation circuit;
the first end of the charge-discharge circuit is used for being connected with a live wire of an alternating current power supply, the second end of the charge-discharge circuit is connected with the first end of the unidirectional conduction circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit, the second end of the unidirectional conduction circuit is used for being connected with a zero line of the alternating current power supply and the second end of the switch circuit, the third end of the switch circuit is connected with the second input end of the optical coupling isolation circuit, and the output end of the optical coupling isolation circuit is used for being connected with a controller;
in the process that the alternating current power supply changes from a wave crest to a wave trough, the switch circuit works in a cut-off state, so that the optical coupling isolation circuit is disconnected, and the optical coupling isolation circuit outputs a high-level signal;
in the process that the alternating current power supply changes from a wave trough to a wave crest, the one-way conduction circuit is in a cut-off state, the switching circuit works in a conduction state, the charge and discharge circuit supplies power to the optical coupling isolation circuit to drive the optical coupling isolation circuit to be conducted, and the optical coupling isolation circuit outputs a low level signal.
2. A zero-crossing detection circuit as claimed in claim 1, wherein the charge and discharge circuit comprises: a first capacitor;
the first end of the first capacitor is used for being connected with a live wire of the alternating current power supply, and the second end of the first capacitor is connected with the first end of the one-way conduction circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit.
3. A zero-crossing detection circuit as claimed in claim 1, wherein the unidirectional conduction circuit comprises: a first diode;
the negative pole of the first diode is connected with the second end of the charge-discharge circuit, the first end of the switch circuit and the first input end of the optical coupling isolation circuit, and the positive pole of the first diode is used for being connected with the zero line of the alternating current power supply and the second end of the switch circuit.
4. A zero-crossing detection circuit as claimed in claim 1, wherein the switching circuit comprises: an NPN triode;
the base electrode of the NPN triode is connected with the second end of the charge-discharge circuit, the first end of the unidirectional conduction circuit and the first input end of the optical coupling isolation circuit;
an emitting electrode of the NPN triode is used for being connected with a zero line of the alternating current power supply and a second end of the one-way conduction circuit;
and the collector of the NPN triode is connected with the second input end of the optical coupling isolation circuit.
5. A zero-crossing detection circuit as claimed in claim 1, wherein the opto-isolator circuit comprises: the optical coupler, the sampling circuit and the first power supply;
the anode of a light emitting diode of the optocoupler is connected with the second end of the charge-discharge circuit, the first end of the unidirectional conduction circuit and the first end of the switch circuit;
the negative electrode of a light emitting diode of the optocoupler is connected with the third end of the switch circuit;
a collector electrode of a phototriode of the optocoupler is connected with an input end of the sampling circuit, a power supply end of the sampling circuit is connected with the first power supply, and an output end of the sampling circuit is used for being connected with a controller;
and an emitting electrode of a phototriode of the optocoupler is grounded.
6. A zero-crossing detection circuit as claimed in claim 5, wherein the sampling circuit comprises: a first resistor, a second resistor and a second capacitor;
the first end of first resistance with first power is connected, the second end of first resistance with the collecting electrode of the phototriode of opto-coupler and the first end of second resistance is connected, the second end of second resistance be used for with the controller with the first end of second electric capacity is connected, the second end ground connection of second electric capacity.
7. A zero-crossing detection circuit as claimed in any of claims 1 to 6, further comprising: a rectification circuit and an electrolytic capacitor;
the first end of the rectifying circuit is connected with the second end of the charging and discharging circuit, the first end of the unidirectional conduction circuit and the first end of the switch circuit, the second end of the rectifying circuit is connected with the first input end of the optical coupling isolation circuit and the anode of the electrolytic capacitor, and the cathode of the electrolytic capacitor is connected with the second end of the unidirectional conduction circuit and the second end of the switch circuit.
8. A zero-crossing detection circuit as claimed in claim 7, wherein the rectifying circuit is a half-bridge rectifying circuit.
9. A zero-crossing detection circuit as claimed in any of claims 1 to 6, further comprising: a protection circuit;
the first end of the protection circuit is connected with the second end of the charge and discharge circuit, the first end of the one-way conduction circuit and the first end of the switch circuit, and the second end of the protection circuit is connected with the first input end of the optical coupling isolation circuit.
10. A zero-crossing detection system, comprising: an alternating current power supply, a controller and a zero-crossing detection circuit as claimed in any one of claims 1 to 9;
the output end of the alternating current power supply is connected with the input end of the zero-crossing detection circuit, and the output end of the zero-crossing detection circuit is connected with the controller;
the zero-crossing detection circuit is used for collecting a zero-crossing signal of the alternating current power supply and sending the zero-crossing information to the controller, so that the controller determines the zero-crossing point of the alternating current power supply according to the zero-crossing signal.
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| CN202020539982.2U CN212364414U (en) | 2020-04-13 | 2020-04-13 | Zero-crossing detection circuit and system thereof |
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| CN202020539982.2U CN212364414U (en) | 2020-04-13 | 2020-04-13 | Zero-crossing detection circuit and system thereof |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113203891A (en) * | 2021-06-04 | 2021-08-03 | 无锡和晶智能科技有限公司 | Detection device and method for double zero crossing points of refrigerator controller |
| CN113934242A (en) * | 2021-10-08 | 2022-01-14 | 冠州科技(广州)有限公司 | Heating control device and heating system |
| CN114113759A (en) * | 2021-12-22 | 2022-03-01 | 杭州联芯通半导体有限公司 | Zero-crossing detection circuit |
| CN114500125A (en) * | 2022-01-21 | 2022-05-13 | 珠海格力电器股份有限公司 | Power supply and communication assembly, system and communication equipment |
| CN117439236A (en) * | 2023-12-18 | 2024-01-23 | 深圳市卓芯微科技有限公司 | Isolation circuit and method of charging contact of beauty instrument and beauty instrument |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113203891A (en) * | 2021-06-04 | 2021-08-03 | 无锡和晶智能科技有限公司 | Detection device and method for double zero crossing points of refrigerator controller |
| CN113934242A (en) * | 2021-10-08 | 2022-01-14 | 冠州科技(广州)有限公司 | Heating control device and heating system |
| CN113934242B (en) * | 2021-10-08 | 2023-08-18 | 冠州科技(广州)有限公司 | Heating control device and heating system |
| CN114113759A (en) * | 2021-12-22 | 2022-03-01 | 杭州联芯通半导体有限公司 | Zero-crossing detection circuit |
| US20230194578A1 (en) * | 2021-12-22 | 2023-06-22 | Hangzhou Lianxintong Semiconductor Co., Ltd. | Zero-Crossing Detection Circuit |
| US11835553B2 (en) * | 2021-12-22 | 2023-12-05 | Hangzhou Lianxintong Semiconductor Co., Ltd. | Zero-crossing detection circuit |
| CN114500125A (en) * | 2022-01-21 | 2022-05-13 | 珠海格力电器股份有限公司 | Power supply and communication assembly, system and communication equipment |
| CN117439236A (en) * | 2023-12-18 | 2024-01-23 | 深圳市卓芯微科技有限公司 | Isolation circuit and method of charging contact of beauty instrument and beauty instrument |
| CN117439236B (en) * | 2023-12-18 | 2024-03-29 | 深圳市卓芯微科技有限公司 | Isolation circuit and method of charging contact of beauty instrument and beauty instrument |
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