Zero-crossing detection circuit with double-path zero-crossing output

Abstract

The utility model discloses a zero-crossing detection circuit with double-path zero-crossing output, which is characterized in that a first port of a first zero-crossing detection chip is connected with a first port of a second zero-crossing detection chip through a plurality of current-limiting resistors, a second port of the first zero-crossing detection chip is connected with a second port of a first optocoupler chip, and a third port of the second zero-crossing detection chip is connected with an input port of a first circuit; a second port of the second zero-cross detection chip is connected with a second port of the second optocoupler chip, and a third port of the second zero-cross detection chip is connected with the input port of the second circuit; a first port of the first optocoupler chip is connected with a first circuit input port through a first energy storage capacitor, a third port of the first optocoupler chip is connected with a third port of the second optocoupler chip, and a fourth port of the first optocoupler chip is connected with a first circuit output port; the first port of the second optocoupler chip is connected with the second circuit input port through the second energy storage capacitor, and the fourth port of the second optocoupler chip is connected with the second circuit output port. And through the high-precision voltage comparator, the precision of the threshold voltage is controlled within an extremely small range, and the moment when the voltage crosses the zero point can be accurately captured.

Description

Technical Field

[0001] This utility model relates to the field of zero-crossing detection technology, and in particular to a zero-crossing point detection circuit with dual-channel zero-crossing output. Background Technology

[0002] Zero-crossing detection technology plays a crucial role in numerous electronic applications today. As electronic products continue to evolve towards miniaturization, energy efficiency, and high precision, traditional zero-crossing detection circuits are increasingly unable to meet the demands.

[0003] Previously, conventional zero-crossing detection circuits suffered from unsatisfactory accuracy due to limitations in the characteristics of the components used and the shortcomings of their design architecture. On one hand, circuits built with discrete resistors, capacitors, and ordinary transistors exhibit significant parameter dispersion. Under different temperature and humidity conditions, resistance and capacitance values ​​are prone to drift, leading to substantial deviations in zero-crossing detection, often exceeding hundreds of microseconds from the actual zero-crossing point. This low accuracy results in frequent signal misalignment and high bit error rates in power line carrier communication, severely impacting communication quality. In phase-sensitive control systems, such as motor speed control systems, phase errors caused by inaccurate zero-crossing can cause motor vibration, reduced efficiency, and even equipment damage. On the other hand, traditional circuits lack effective anti-interference mechanisms to cope with the complex noise environment of power lines. Power lines, as a shared channel for energy and signal transmission, are filled with various frequencies of harmonics, spikes, and other noise. Ordinary circuits, lacking sophisticated filtering and hysteresis processing capabilities, easily misinterpret this noise as zero-crossing signals, resulting in chaotic and disordered detection results and severely compromising system stability. Summary of the Invention

[0004] The purpose of this utility model embodiment is to provide a zero-crossing detection circuit with dual-channel zero-crossing output. By using a high-precision voltage comparator, the accuracy of its threshold voltage is controlled within a very small range, which can accurately capture the moment when the voltage crosses the zero point from positive to negative or from negative to positive. The deviation from the actual zero-crossing point is less than 10µs, providing a reliable time reference for a series of subsequent applications.

[0005] To solve the above technical problems, this utility model provides a zero-crossing detection circuit with dual-channel zero-crossing output, including: a first circuit input port, a second circuit input port, a signal detection component, a signal processing component, a first circuit output port, and a second circuit output port;

[0006] The signal detection component includes: a first zero-crossing detection chip and a second zero-crossing detection chip; the signal processing component includes: a first optocoupler chip and a second optocoupler chip.

[0007] The first port of the first zero-crossing detection chip is connected to the first port of the second zero-crossing detection chip through several current-limiting resistors, its second port is connected to the second port of the first optocoupler chip, and its third port is connected to the first circuit input port.

[0008] The second port of the second zero-crossing detection chip is connected to the second port of the second optocoupler chip, and its third port is connected to the second circuit input port;

[0009] The first port of the first optocoupler chip is connected to the input port of the first circuit through the first energy storage capacitor, its third port is connected to the third port of the second optocoupler chip, and its fourth port is connected to the output port of the first circuit.

[0010] The first port of the second optocoupler chip is connected to the input port of the second circuit through the second energy storage capacitor, and its fourth port is connected to the output port of the second circuit.

[0011] Furthermore, the plurality of current-limiting resistors include: a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, and a fourth current-limiting resistor connected in series.

[0012] Furthermore, the zero-crossing detection circuit for the dual-channel zero-crossing output also includes: a fifth current-limiting resistor and a sixth current-limiting resistor;

[0013] The fifth current-limiting resistor is connected to the first port and the second port of the first optocoupler chip, respectively.

[0014] The sixth current-limiting resistor is connected to the first port and the second port of the second optocoupler chip, respectively.

[0015] Furthermore, the zero-crossing detection circuit for the dual-channel zero-crossing output also includes: a first filter capacitor and a second filter capacitor;

[0016] One end of the first filter capacitor is connected to the fourth port of the first optocoupler chip, and the other end is grounded;

[0017] One end of the second filter capacitor is connected to the fourth port of the second optocoupler chip, and the other end is grounded.

[0018] Furthermore, the zero-crossing detection circuit for the dual-channel zero-crossing output also includes: a first voltage-regulating resistor and a second voltage-regulating resistor;

[0019] One end of the first voltage regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the first optocoupler chip.

[0020] One end of the second voltage regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the second optocoupler chip.

[0021] Furthermore, the first zero-crossing detection chip and the second zero-crossing detection chip are both GS1102 chips.

[0022] Furthermore, the first optocoupler chip and the second optocoupler chip are respectively LTV-816S-TA1-D3-TX optocoupler chips.

[0023] The above-described technical solution of this utility model embodiment has the following beneficial technical effects:

[0024] 1. Employing a high-precision voltage comparator, the threshold voltage is accurate and stable, with a deviation from the actual zero-crossing point of less than 10µs. In the field of power line carrier communication, it ensures precise alignment of signal transmission time slots, significantly reducing the bit error rate and improving communication quality; in motor control scenarios, it provides strong support for precise phase control, avoiding motor jitter and efficiency loss due to phase errors, and ensuring stable and efficient equipment operation.

[0025] 2. The superior characteristic of a static operating current of less than 10uA greatly expands the application range of the circuit. It is especially suitable for portable devices that rely on battery power, such as smart lighting fixtures and outdoor sensor nodes, which can significantly extend battery life, reduce the inconvenience of frequent battery replacements, and reduce the energy consumption cost of long-term device operation;

[0026] 3. The circuit has a high degree of integration and requires fewer external components, which effectively simplifies the circuit board design, reduces the PCB area occupied, and lowers material costs and assembly difficulty. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the zero-crossing detection circuit structure with dual-channel zero-crossing output provided in this embodiment of the utility model;

[0028] Figure 2 This is a schematic diagram of the zero-crossing detection voltage waveform provided in this embodiment of the utility model;

[0029] Figure 3 This is a schematic diagram of the zero-crossing detection output provided in an embodiment of this utility model. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this utility model. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of this utility model.

[0031] Please refer to Figure 1This utility model embodiment provides a zero-crossing detection circuit with dual-channel zero-crossing output, including: a first circuit input port, a second circuit input port, a signal detection component, a signal processing component, a first circuit output port, and a second circuit output port; the signal detection component includes: a first zero-crossing detection chip and a second zero-crossing detection chip, and the signal processing component includes: a first optocoupler chip and a second optocoupler chip; the first port of the first zero-crossing detection chip and the first port of the second zero-crossing detection chip are connected through several current-limiting resistors, the second port of the first zero-crossing detection chip is connected to the second port of the first optocoupler chip, and the third port of the first zero-crossing detection chip is connected to the first circuit input port; the second port of the second zero-crossing detection chip is connected to the second port of the second optocoupler chip, and the third port of the second zero-crossing detection chip is connected to the second circuit input port; the first port of the first optocoupler chip is connected to the first circuit input port through a first energy storage capacitor, the third port of the first optocoupler chip is connected to the third port of the second optocoupler chip, and the fourth port of the second optocoupler chip is connected to the first circuit output port; the first port of the second optocoupler chip is connected to the second circuit input port through a second energy storage capacitor, and the fourth port of the second optocoupler chip is connected to the second circuit output port.

[0032] The first and second zero-crossing detection chips in the aforementioned signal detection component monitor voltage changes from two input ports, respectively. Their first ports are connected via several current-limiting resistors. This connection method balances and adjusts the electrical parameters between the chips, ensuring they operate under similar conditions and improving detection consistency and accuracy. The second port of each zero-crossing detection chip is connected to the second port of its corresponding optocoupler chip, establishing a signal transmission channel so that the voltage changes acquired by the zero-crossing detection chip can be transmitted to the subsequent optocoupler chip for processing. The third port is directly connected to the circuit input port, ensuring that the chip can capture the dynamics of the input voltage in real time and accurately, detecting the process of the voltage approaching zero as soon as possible.

[0033] The first and second optocoupler chips serve two main functions. First, they isolate the high-voltage signal region on the input side from the low-voltage signal region on the output side, preventing damage to subsequent low-voltage circuits from high voltage and high current, thus ensuring the safety of the entire system. Second, they convert the input electrical signal to meet the electrical requirements of subsequent circuits. The first port of the optocoupler chip is connected to the corresponding circuit input port through an energy storage capacitor. Near the voltage zero-crossing point, the capacitor stores a certain amount of energy, maintaining the stable operation of the optocoupler chip during this brief moment. This prevents malfunction due to a sudden voltage drop, ensuring the continuity and reliability of the output signal.

[0034] Meanwhile, the third ports of the two optocouplers are interconnected, enabling signal synchronization or sharing, further optimizing the correlation between the dual output signals, and achieving better coordination in terms of timing and logic. The fourth ports of both are connected to their respective circuit output ports, outputting the processed, precise zero-crossing detection signal to external devices.

[0035] Dual-channel zero-crossing detection circuits can be used for monitoring two-phase voltage in three-phase power systems. By accurately detecting the zero-crossing points of the two voltages, the voltage phase relationship can be determined in real time, thereby judging whether the three-phase power is balanced. Once an imbalance occurs, alarms or adjustment devices can be triggered in a timely manner to ensure the stable operation of the power system and avoid problems such as motor overheating and reduced efficiency caused by three-phase imbalance.

[0036] Furthermore, the current-limiting resistors include: a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, and a fourth current-limiting resistor connected in series.

[0037] The total resistance of a series resistor is equal to the sum of the individual resistances. This cumulative effect allows circuit designers to precisely adjust the current flowing into the first port of the zero-crossing detection chip based on its electrical characteristics. When selecting zero-crossing detection chips of different accuracies and power ratings, adjusting the combination of the four current-limiting resistors (e.g., using high-precision metal film resistors and calculating a suitable total resistance) ensures that the chip operates stably within its rated current range, preventing overheating and damage due to excessive current or affecting detection sensitivity due to insufficient current.

[0038] In alternating voltage environments, current is highly susceptible to fluctuations, especially when the external power supply network experiences sudden load changes or harmonic interference. Four series-connected current-limiting resistors effectively reduce the amplitude of these fluctuations. When the current increases instantaneously, the larger total resistance limits the excessive current surge, preventing damage to the zero-crossing detection chip from excessive current surges. This ensures that the current signal received by the chip is relatively stable, thereby guaranteeing the accuracy of its zero-crossing point determination.

[0039] Furthermore, the zero-crossing detection circuit for dual-channel zero-crossing output also includes: a fifth current-limiting resistor and a sixth current-limiting resistor; the fifth current-limiting resistor is connected to the first port and the second port of the first optocoupler chip respectively; the sixth current-limiting resistor is connected to the first port and the second port of the second optocoupler chip respectively.

[0040] The LEDs in an optocoupler chip are highly sensitive to current; excessive current can easily cause them to overheat or even burn out, leading to the failure of the entire optocoupler chip. The fifth and sixth current-limiting resistors, based on Ohm's law, limit the current through their resistance, ensuring that even under different input voltage conditions, including momentary voltage peaks or fluctuations, the current flowing into the LED remains within a safe operating range. For example, when strong electromagnetic interference causes a brief spike in the input voltage, the current-limiting resistors can quickly reduce the spike current, protecting the optocoupler chip from damage and maintaining its stable photoelectric conversion function. Furthermore, the luminous intensity of the LED in the optocoupler chip may change during prolonged operation or under different operating temperatures, affecting the accuracy of the phototransistor (or photodiode) signal reception and consequently the output signal quality of the entire circuit. The fifth and sixth current-limiting resistors, by providing a relatively stable current to the LED, ensure that the luminous intensity remains as consistent as possible. Regardless of changes in the external environment, as long as the input voltage is within the design range, the optocoupler chip can drive the phototransistor (or photodiode) to work with a relatively stable luminous intensity, ensuring the accuracy and reliability of signal transmission and laying the foundation for the stability of subsequent dual-channel output signals.

[0041] Furthermore, the zero-crossing detection circuit for dual-channel zero-crossing output also includes: a first filter capacitor and a second filter capacitor; one end of the first filter capacitor is connected to the fourth port of the first optocoupler chip, and the other end is grounded; one end of the second filter capacitor is connected to the fourth port of the second optocoupler chip, and the other end is grounded.

[0042] Although the zero-crossing detection signal output by the optocoupler chip has undergone preliminary processing, it may still contain high-frequency noise generated by the operation of internal components and noise introduced by external electromagnetic interference. The first and second filter capacitors utilize their capacitive reactance characteristics to AC power; that is, they present low impedance to high-frequency signals, allowing high-frequency noise to flow smoothly to ground, while presenting high impedance to low-frequency zero-crossing detection signals, preserving them as much as possible and ensuring a relatively pure and stable zero-crossing detection signal output from the port. Besides resisting high-frequency interference, the filter capacitors also help stabilize the baseline of the output signal. During dynamic circuit operation, due to factors such as power supply fluctuations and load changes, the DC level of the optocoupler chip's output signal may experience slight drift. If this drift accumulates, it can cause errors in subsequent judgments based on the zero-crossing detection signal. The first and second filter capacitors, by storing and releasing charge, play a certain "voltage stabilization" role, maintaining the DC level of the output signal within a relatively stable range, ensuring the repeatability and accuracy of each zero-crossing detection signal output, and providing a reliable signal reference for connected subsequent circuits.

[0043] Furthermore, the zero-crossing detection circuit with dual-channel zero-crossing output also includes: a first voltage-regulating resistor and a second voltage-regulating resistor; one end of the first voltage-regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the first optocoupler chip; one end of the second voltage-regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the second optocoupler chip.

[0044] The voltage provided by an external power supply typically has a fixed amplitude, but the load circuits connected to the zero-crossing detection signal output by the optocoupler chip may have different input voltage requirements. The first and second regulating resistors utilize their own resistive characteristics to precisely control the voltage input to the load circuit by appropriately setting their resistance values. When the load circuit requires a lower voltage zero-crossing detection signal, the resistance value of the regulating resistor is increased, resulting in a larger voltage drop across the resistor, thereby reducing the voltage applied to the load. Conversely, if the load requires a higher voltage signal, the resistance value is appropriately decreased to ensure the load receives a suitable operating voltage. Furthermore, the first and second regulating resistors can be customized to the characteristics of different loads, ensuring stable operation under suitable voltage conditions for both precision instruments and conventional equipment, effectively expanding the breadth and depth of circuit applications.

[0045] Optionally, the first zero-crossing detection chip and the second zero-crossing detection chip are both GS1102 chips.

[0046] Optionally, the first optocoupler chip and the second optocoupler chip are respectively LTV-816S-TA1-D3-TX optocoupler chips.

[0047] like Figure 1 As shown, in a specific embodiment of this utility model, the first current-limiting resistor R11, the second current-limiting resistor R12, the third current-limiting resistor R13, and the fourth current-limiting resistor R14 are surface-mount resistors with a resistance of 750KΩ, serving as voltage-limiting and current-limiting resistors; the first voltage-regulating resistor R15 and the second voltage-regulating resistor R10 are also surface-mount resistors with a resistance of 4.7KΩ, mainly serving as current-limiting resistors; the first energy storage capacitor C3 and the second energy storage capacitor C6 are surface-mount capacitors with a capacitance of 56nF, serving as energy storage capacitors; the first filter capacitor C4 and the second filter capacitor C5 are also surface-mount capacitors with a capacitance of 1nF, serving as output filter capacitors; the first voltage-regulating resistor R9 and the second voltage-regulating resistor R16 are surface-mount resistors with a resistance of 10KΩ, serving as voltage pull-up resistors; the first zero-crossing detection chip U3 and the second zero-crossing detection chip U6 are zero-crossing detection chips; the first optocoupler chip U4 and the second optocoupler chip U5 are optocouplers that provide strong and weak current isolation for communication. The zero-crossing detection circuit has an input voltage of 220V AC. It outputs zero-crossing detection signals at the two zero-crossing points of the AC sine wave. See the waveform of the zero-crossing detection chip for details. Figure 2 and Figure 3 .

[0048] This utility model embodiment aims to protect a zero-crossing point detection circuit with dual-channel zero-crossing output, comprising: a first circuit input port, a second circuit input port, a signal detection component, a signal processing component, a first circuit output port, and a second circuit output port; the signal detection component includes: a first zero-crossing detection chip and a second zero-crossing detection chip; the signal processing component includes: a first optocoupler chip and a second optocoupler chip; the first port of the first zero-crossing detection chip and the first port of the second zero-crossing detection chip are connected through several current-limiting resistors, the second port of the first zero-crossing detection chip is connected to the second port of the first optocoupler chip, and the third port of the second zero-crossing detection chip is connected to the second circuit input port; the first port of the first optocoupler chip is connected to the first circuit input port through a first energy storage capacitor, the third port of the first optocoupler chip is connected to the third port of the second optocoupler chip, and the fourth port of the first optocoupler chip is connected to the first circuit output port; the first port of the second optocoupler chip is connected to the second circuit input port through a second energy storage capacitor, and the fourth port of the second optocoupler chip is connected to the second circuit output port. The above technical solution has the following effects:

[0049] 1. Employing a high-precision voltage comparator, the threshold voltage is accurate and stable, with a deviation from the actual zero-crossing point of less than 10µs. In the field of power line carrier communication, it ensures precise alignment of signal transmission time slots, significantly reducing the bit error rate and improving communication quality; in motor control scenarios, it provides strong support for precise phase control, avoiding motor jitter and efficiency loss due to phase errors, and ensuring stable and efficient equipment operation.

[0050] 2. The superior characteristic of a static operating current of less than 10uA greatly expands the application range of the circuit. It is especially suitable for portable devices that rely on battery power, such as smart lighting fixtures and outdoor sensor nodes, which can significantly extend battery life, reduce the inconvenience of frequent battery replacements, and reduce the energy consumption cost of long-term device operation;

[0051] 3. The circuit has a high degree of integration and requires fewer external components, which effectively simplifies the circuit board design, reduces the PCB area occupied, and lowers material costs and assembly difficulty.

[0052] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of this utility model and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of this utility model should be included within its protection scope. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A zero-crossing detection circuit with dual-channel zero-crossing output, characterized in that, include: The circuit includes a first circuit input port, a second circuit input port, a signal detection component, a signal processing component, a first circuit output port, and a second circuit output port. The signal detection component includes: a first zero-crossing detection chip and a second zero-crossing detection chip; the signal processing component includes: a first optocoupler chip and a second optocoupler chip. The first port of the first zero-crossing detection chip is connected to the first port of the second zero-crossing detection chip through several current-limiting resistors, its second port is connected to the second port of the first optocoupler chip, and its third port is connected to the first circuit input port. The second port of the second zero-crossing detection chip is connected to the second port of the second optocoupler chip, and its third port is connected to the second circuit input port; The first port of the first optocoupler chip is connected to the input port of the first circuit through the first energy storage capacitor, its third port is connected to the third port of the second optocoupler chip, and its fourth port is connected to the output port of the first circuit. The first port of the second optocoupler chip is connected to the input port of the second circuit through the second energy storage capacitor, and its fourth port is connected to the output port of the second circuit.

2. The zero-crossing detection circuit with dual-channel zero-crossing output according to claim 1, characterized in that, The plurality of current-limiting resistors include: a first current-limiting resistor, a second current-limiting resistor, a third current-limiting resistor, and a fourth current-limiting resistor connected in series.

3. The zero-crossing detection circuit with dual-channel zero-crossing output according to claim 1, characterized in that, Also includes: The fifth and sixth current-limiting resistors; The fifth current-limiting resistor is connected to the first port and the second port of the first optocoupler chip, respectively. The sixth current-limiting resistor is connected to the first port and the second port of the second optocoupler chip, respectively.

4. The zero-crossing detection circuit with dual-channel zero-crossing output according to claim 1, characterized in that, Also includes: First filter capacitor and second filter capacitor; One end of the first filter capacitor is connected to the fourth port of the first optocoupler chip, and the other end is grounded; One end of the second filter capacitor is connected to the fourth port of the second optocoupler chip, and the other end is grounded.

5. The zero-crossing detection circuit with dual-channel zero-crossing output according to claim 1, characterized in that, Also includes: First voltage regulating resistor and second voltage regulating resistor; One end of the first voltage regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the first optocoupler chip. One end of the second voltage regulating resistor is connected to an external power supply, and the other end is connected to the fourth port of the second optocoupler chip.

6. The zero-crossing detection circuit with dual-channel zero-crossing output according to any one of claims 1-5, characterized in that, The first zero-crossing detection chip and the second zero-crossing detection chip are both GS1102 chips.

7. The zero-crossing detection circuit with dual-channel zero-crossing output according to any one of claims 1-5, characterized in that, The first optocoupler chip and the second optocoupler chip are respectively LTV-816S-TA1-D3-TX optocoupler chips.

Images