Energy-saving low-power-consumption isolation zero-cross detection circuit

Abstract

The utility model provides an energy-saving low-power-consumption isolation zero-cross detection circuit. The energy-saving low-power-consumption isolation zero-cross detection circuit comprises resistors R1, R2, R3, R4, R5, R6, R7 and R8, rectifier diodes D1 and D2, an electrolytic capacitor EC1, a triode Q1 and an optocoupler U1. The energy-saving low-power-consumption isolation zero-cross detection circuit is simple in structure and ingenious in design, loss of mains supply voltage to the optocoupler series connection resistor can be reduced, and the low-power-consumption function is achieved through the resistor connected with the optocoupler in series after the voltage division on the resistor and the rectifier diode are rectified and filtered through the electrolytic capacitor. And moreover, effective low voltage is obtained by charging the electrolytic capacitor after rectification, and the loss of the commercial power caused by the divider resistor is effectively reduced by amplifying the current through the triode.

Description

Technical Field

[0001] The utility model relates to a zero-crossing detection circuit, in particular to an energy-saving, low-power-consumption isolated zero-crossing detection circuit. Background Art

[0002] Currently, a wide range of products on the market require isolation solutions, such as heating water dispensers, rice cookers, and toilet lids. Most of these products require temperature and speed control, both of which rely on zero-crossing signals. Common circuits use optocouplers to directly draw voltage from the mains to achieve zero-crossing. However, existing isolated zero-crossing solutions employ an optocoupler in series with a resistor, drawing power directly from both ends of the mains. However, as the mains voltage fluctuates, the optocoupler draws a constant drive current, requiring a small resistor value to achieve a stable square wave. However, this resistive voltage drop method generates significant losses, with most of the energy dissipated by the resistor. Utility Model Content

[0003] In view of the shortcomings of the existing technology, the utility model proposes an energy-saving and low-power isolated zero-crossing detection circuit, which reduces the voltage applied to the resistor, reduces the resistance loss of the optocoupler in series, improves the power consumption of the entire device, and achieves energy-saving effects.

[0004] In order to realize the above technical solution, the present invention provides an energy-saving and low-power consumption isolated zero-crossing detection circuit, comprising: resistors R1, R2, R3, R4, R5, R7, rectifier diodes D1, D2, electrolytic capacitor EC1, transistor Q1 and optocoupler U1, wherein one end of the resistor R1 is connected to ACN in the mains, the other end of the resistor R1 is connected to the resistor R5, the other end of the resistor R5 is connected to ACL in the mains, one end of the resistor R3 is connected to the connecting line between the resistor R1 and the resistor R5, the other end of the resistor R3 is connected to pin 1 of the optocoupler U1, one end of the rectifier diode D1 is connected to the connecting line between the resistor R1 and the mains ACN, the other end of the rectifier diode D1 is connected to the rectifier diode D2, and the other end of the rectifier diode D2 is connected to the resistor R1. R5 is connected to the connection line of the mains ACL, one end of the electrolytic capacitor EC1 is connected to the connection line of the resistor R1 and the resistor R5, the other end of the electrolytic capacitor EC1 is connected to the connection line of the rectifier diode D1 and the rectifier diode D2, one end of the resistor R7 is connected to the connection line of the rectifier diode D2 and the resistor R5, the other end of the resistor R7 is connected to the B pole of the transistor Q1, the C pole of the transistor Q1 is connected to the 2 pin of the optocoupler U1, the E pole of the transistor Q1 is connected to the connection line of the electrolytic capacitor EC1 and the rectifier diode D2, one end of the resistor R2 is connected to the 4 pin of the optocoupler U1, the other end of the resistor R2 is connected to the DC power VCC, one end of the resistor R4 is connected to the connection line of the resistor R2 and the 4 pin of the optocoupler U1, and the other end of the resistor R4 is connected to the IO pin of the MCU.

[0005] In the above technical solution, during actual operation, AC power ACN flows through resistor R1 to electrolytic capacitor EC1, then to rectifier diode D2, and then to AC power ACL, at which point electrolytic capacitor EC1 is charged. AC power ACL flows through resistor R5 to electrolytic capacitor EC1, then to rectifier diode D1, and then to AC power ACN, at which point electrolytic capacitor EC1 is charged again. AC power ACL flows through resistor R7 to the B terminal of transistor Q1. After the current flows from the B terminal of transistor Q1 to the E terminal, transistor Q1 performs current amplification. The current then flows from the E terminal of transistor Q1 to the rectifier diode D1, and then returns to AC power ACN. The positive current of the electrolytic capacitor EC1 flows through the resistor R3 to the 1st pin of the optocoupler U1, and the current flows from the 1st pin of the optocoupler U1 to the 2nd pin of the optocoupler U1. The light-emitting diode in the optocoupler U1 lights up, and the 2nd pin of the optocoupler U1 flows to the C pole of the transistor Q1, and then to the E pole of the transistor Q1 and back to the negative pole of the electrolytic capacitor EC1 to form a loop. The divided voltage of the discharge resistor in parallel with the electrolytic capacitor EC1 is rectified to charge the electrolytic capacitor EC1 to obtain an effective low voltage. The current is amplified by the transistor Q1, which effectively reduces the loss of the voltage divider resistor to the mains, thereby reducing the loss of the mains voltage to the series resistor of the optocoupler U1. When the DC power VCC passes through the resistor R2 to the 4th pin of the optocoupler U1, the transistor inside the optocoupler U1 receives the light from the light-emitting diode inside the optocoupler U1, and the transistor inside the optocoupler U1 conducts current to the ground. One end of the resistor R4 is connected to the resistor R2 and the 4th pin of the U1 optocoupler. The high and low level signals flow through the resistor R4 to the IO pin of the MCU, and then are sent to the MCU for processing.

[0006] Preferably, the energy-saving and low-power isolated zero-crossing detection circuit also includes a resistor R6, one end of which is connected to the connection line between the E pole of the transistor Q1 and the electrolytic capacitor EC1, and the other end of the resistor R6 is connected to the connection line between the B pole of the transistor Q1 and the resistor R7.

[0007] Preferably, the energy-saving and low-power isolated zero-crossing detection circuit further includes a resistor R8, one end of which is connected to the connecting line between the resistor R1 and the resistor R5, and the other end of the resistor R8 is connected to the connecting line between the rectifier diode D1 and the rectifier diode D2.

[0008] The beneficial effect of the energy-saving, low-power consumption isolated zero-crossing detection circuit provided by the present utility model is that: the energy-saving, low-power consumption isolated zero-crossing detection circuit has a simple structure and an ingenious design. By reducing the voltage applied to the resistor, the resistance loss of the optocoupler in series is reduced, the power consumption of the entire machine is improved, and the energy-saving effect is achieved. During actual operation, the divided voltage of the discharge resistor in parallel with the electrolytic capacitor EC1 is rectified and then charged to the electrolytic capacitor EC1 to obtain an effective low voltage. The current is amplified by the transistor Q1, effectively reducing the loss of the voltage-dividing resistor to the mains. The divided voltage on the discharge resistor is rectified and filtered by the electrolytic capacitor EC1 and then applied to the resistor in series with the optocoupler U1 to achieve a low-power function, thereby reducing the loss of the mains voltage to the series resistor of the optocoupler U1, achieving low power consumption of the entire machine and achieving an energy-saving effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a circuit diagram of the utility model. DETAILED DESCRIPTION

[0010] The following is a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary persons in this field without creative work are within the scope of protection of the present invention.

[0011] Embodiment: An energy-saving and low-power consumption isolated zero-crossing detection circuit.

[0012] Reference Figure 1As shown, an energy-saving and low-power isolated zero-crossing detection circuit includes: resistors R1, R2, R3, R4, R5, R6, R7, R8, rectifier diodes D1, D2, electrolytic capacitor EC1, transistor Q1 and optocoupler U1, wherein one end of the resistor R1 is connected to ACN in the mains, the other end of the resistor R1 is connected to the resistor R5, the other end of the resistor R5 is connected to ACL in the mains, one end of the resistor R3 is connected to the connecting line between the resistor R1 and the resistor R5, the other end of the resistor R3 is connected to pin 1 of the optocoupler U1, one end of the rectifier diode D1 is connected to the connecting line between the resistor R1 and the mains ACN, the other end of the rectifier diode D1 is connected to the rectifier diode D2, the other end of the rectifier diode D2 is connected to the connecting line between the resistor R5 and the mains ACL, one end of the electrolytic capacitor EC1 is connected to the connecting line between the resistor R1 and the resistor R5, and the other end of the electrolytic capacitor EC1 is connected to the connecting line between the rectifier diode D1 and On the connecting line of the rectifier diode D2, one end of the resistor R7 is connected to the connecting line between the rectifier diode D2 and the resistor R5, the other end of the resistor R7 is connected to the B pole of the transistor Q1, the C pole of the transistor Q1 is connected to the 2 pin of the optocoupler U1, the E pole of the transistor Q1 is connected to the connecting line between the electrolytic capacitor EC1 and the rectifier diode D2, one end of the resistor R6 is connected to the connecting line between the E pole of the transistor Q1 and the electrolytic capacitor EC1, the other end of the resistor R6 is connected to the connecting line between the B pole of the transistor Q1 and the resistor R7, one end of the resistor R8 is connected to the connecting line between the resistor R1 and the resistor R5, the other end of the resistor R8 is connected to the connecting line between the rectifier diode D1 and the rectifier diode D2, one end of the resistor R2 is connected to the 4 pin of the optocoupler U1, the other end of the resistor R2 is connected to the DC power VCC, one end of the resistor R4 is connected to the connecting line between the resistor R2 and the 4 pin of the optocoupler U1, and the other end of the resistor R4 is connected to the IO pin of the MCU.

[0013] The operating principle of this energy-saving, low-power isolated zero-crossing detection circuit is as follows. During actual operation, AC current ACN flows through resistor R1 to electrolytic capacitor EC1, then to rectifier diode D2, and then to AC current ACL, at which point electrolytic capacitor EC1 is charged. AC current ACL flows through resistor R5 to electrolytic capacitor EC1, then to rectifier diode D1, and then to AC current ACN, at which point electrolytic capacitor EC1 is charged again. AC current ACL flows through resistor R7 to the B terminal of transistor Q1. After the current flows from the B terminal of transistor Q1 to the E terminal, transistor Q1 performs current amplification. The current then flows from the E terminal of transistor Q1 to the rectifier diode D1 and back to AC current ACN. The positive current of the electrolytic capacitor EC1 flows through the resistor R3 to the 1st pin of the optocoupler U1, and the current flows from the 1st pin of the optocoupler U1 to the 2nd pin of the optocoupler U1. The light-emitting diode in the optocoupler U1 lights up, and the 2nd pin of the optocoupler U1 flows to the C pole of the transistor Q1, and then to the E pole of the transistor Q1 and back to the negative pole of the electrolytic capacitor EC1 to form a loop. The divided voltage of the discharge resistor in parallel with the electrolytic capacitor EC1 is rectified to charge the electrolytic capacitor EC1 to obtain an effective low voltage. The current is amplified by the transistor Q1, which effectively reduces the loss of the voltage divider resistor to the mains, thereby reducing the loss of the mains voltage to the series resistor of the optocoupler U1. When the DC power VCC passes through the resistor R2 to the 4th pin of the optocoupler U1, the transistor inside the optocoupler U1 receives the light from the light-emitting diode inside the optocoupler U1, and the transistor inside the optocoupler U1 conducts current to the ground. One end of the resistor R4 is connected to the resistor R2 and the 4th pin of the U1 optocoupler. The high and low level signals flow through the resistor R4 to the IO pin of the MCU, and then are sent to the MCU for processing.

[0014] This energy-saving, low-power isolated zero-crossing detection circuit has a simple structure and ingenious design. By reducing the voltage applied to the resistor, the resistance loss of the optocoupler in series is reduced, and the power consumption of the entire device is improved, achieving energy-saving effects. During actual operation, the divided voltage of the discharge resistor in parallel with electrolytic capacitor EC1 is rectified and then charged to electrolytic capacitor EC1 to obtain an effective low voltage. The current is amplified by transistor Q1, effectively reducing the loss of the voltage-dividing resistor to the mains. The divided voltage on the discharge resistor is rectified and filtered by electrolytic capacitor EC1 and then applied to the resistor in series with optocoupler U1 to achieve a low-power function, thereby reducing the loss of the mains voltage to the series resistor of optocoupler U1, achieving low power consumption of the entire device and achieving energy-saving effects.

[0015] The above description is only a preferred embodiment of the present invention, but the present invention should not be limited to the contents disclosed in the embodiment and the drawings. Therefore, any equivalent or modification completed without departing from the spirit disclosed in the present invention shall fall within the scope of protection of the present invention.

Claims

1. An energy-saving and low-power isolated zero-crossing detection circuit, characterized in that include: Resistors R1, R2, R3, R4, R5, R7, rectifier diodes D1, D2, electrolytic capacitor EC1, transistor Q1 and optocoupler U1, wherein one end of the resistor R1 is connected to the ACN in the mains, the other end of the resistor R1 is connected to the resistor R5, the other end of the resistor R5 is connected to the ACL in the mains, one end of the resistor R3 is connected to the connecting line between the resistor R1 and the resistor R5, the other end of the resistor R3 is connected to pin 1 of the optocoupler U1, one end of the rectifier diode D1 is connected to the connecting line between the resistor R1 and the mains ACN, the other end of the rectifier diode D1 is connected to the rectifier diode D2, the other end of the rectifier diode D2 is connected to the connecting line between the resistor R5 and the mains ACL, the electrolytic capacitor E One end of C1 is connected to the connecting line between resistor R1 and resistor R5, the other end of electrolytic capacitor EC1 is connected to the connecting line between rectifier diode D1 and rectifier diode D2, one end of resistor R7 is connected to the connecting line between rectifier diode D2 and resistor R5, the other end of resistor R7 is connected to the B pole of transistor Q1, the C pole of transistor Q1 is connected to pin 2 of optocoupler U1, the E pole of transistor Q1 is connected to the connecting line between electrolytic capacitor EC1 and rectifier diode D2, one end of resistor R2 is connected to pin 4 of optocoupler U1, the other end of resistor R2 is connected to DC power VCC, one end of resistor R4 is connected to the connecting line between resistor R2 and pin 4 of optocoupler U1, and the other end of resistor R4 is connected to the IO pin of MCU.

2. The energy-saving, low-power consumption isolated zero-crossing detection circuit according to claim 1, wherein: It also includes a resistor R6, one end of which is connected to the connection line between the E pole of the transistor Q1 and the electrolytic capacitor EC1, and the other end of the resistor R6 is connected to the connection line between the B pole of the transistor Q1 and the resistor R7.

3. The energy-saving, low-power consumption isolated zero-crossing detection circuit according to claim 2, wherein: The device further includes a resistor R8 , one end of which is connected to the connection line between the resistor R1 and the resistor R5 , and the other end of which is connected to the connection line between the rectifier diode D1 and the rectifier diode D2 .

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