Low-cost simple circuit with zero-cross detection
Through the low-cost simple circuit with its own zero crossing detection, the use of optocouplers and thyristor control circuits, the problems of inaccurate and high cost of zero crossing detection in the prior art are solved, and accurate switching and circuit simplification of load at zero crossing point is achieved.
Patent Information
- Application Number
- CN202422220457.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-07-18
- Estimated Expiration
- 2034-09-10
AI Technical Summary
The existing zero-crossing detection circuit has a time deviation, resulting in inaccurate load switches, failure to pass EMC detection, and complex structure and high cost.
It adopts a low-cost simple circuit with its own zero crossing detection, and uses its own zero crossing optoelectronic coupler and thyristor control circuit to control the zero crossing point conduction of the load through the output electrical signal of the microcontroller, simplifying the circuit structure.
It realizes accurate switching at zero crossing point, reduces production costs, simplifies the circuit, and meets the EMC detection requirements.
Smart Images
Figure CN223123110U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electronic devices, in particular to a low-cost and simple circuit with zero-crossing detection Background Art
[0002] At present, the zero-crossing detection circuit is used to detect the zero-crossing point of alternating current and is applied in many circuits. In the prior art, the zero-crossing detection circuit for isolating alternating current from direct current has the following problems: The existing detection circuit that detects the zero-crossing point through software has a time deviation, resulting in the inability to switch the load exactly at the zero-crossing point, so that the product is not easy to pass the EMC detection. Therefore, it cannot meet the application requirements of truly controlling the load output at the zero-crossing point. At the same time, the existing zero-crossing detection circuit structure is too complex, with high failure rate and production cost Summary of the Utility Model
[0003] The utility model provides a low-cost and simple circuit with zero-crossing detection to overcome the above deficiencies of the prior art
[0004] The technical solution of the utility model is: A low-cost and simple circuit with zero-crossing detection, characterized in that it includes a load connected to the 220V mains circuit, a thyristor control circuit, and a zero-crossing optocoupler. The load is connected in series with the thyristor control circuit. One end of the zero-crossing optocoupler is connected to the live wire after connecting resistor R95, and the other end is commonly connected to resistor R47 and the control pole of the thyristor. The photodiode of the zero-crossing optocoupler is connected to the +5V current-limiting circuit and the BTA control port of the single-chip microcomputer. The single-chip microcomputer outputs an electrical signal to make the zero-crossing optocoupler conduct when the current passes through zero, so that the thyristor conducts and the load works
[0005] The load is an electric heater, or an LED lamp, or a motor
[0006] The thyristor control circuit includes a thyristor and its absorption circuit, and the absorption circuit includes a capacitor and resistor R99 connected in series
[0007] The absorption circuit is connected in parallel to the two ports of the thyristor. One end of the capacitor is connected to resistor R99, and the other end is connected to the live wire. The other end of resistor R99 is commonly connected to resistor R47 and anti-interference inductor LL1. The anti-interference inductor LL1 is connected to the load
[0008] The +5V current-limiting circuit includes a pull-up resistor R93 and a current-limiting resistor R94. The common connection end of the pull-up resistor R93 and the current-limiting resistor R94 is connected to the +5V power supply. The other end of the pull-up resistor R93 is connected to the photodiode and the BTA control port of the single-chip microcomputer
[0009] The utility model has the following beneficial effects: By replacing the zero-crossing detection circuit in the prior art with a built-in zero-crossing optocoupler, the production cost is reduced, the circuit is simplified, and the application requirement of two zero-crossing pulses per sine period is met. Description of the Drawings
[0010] Figure 1 It is a schematic diagram of a low-cost and simple circuit with built-in zero-crossing detection of the utility model. Specific Embodiments
[0011] Next, the technical solutions of the present application will be clearly and completely described in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments.
[0012] Generally, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents the selected embodiments of the present application.
[0013] Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.
[0014] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.
[0015] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.
[0016] The utility model discloses a low-cost and simple circuit with zero-crossing detection, which includes a load connected to a 220V mains circuit, a thyristor control circuit, and a built-in zero-crossing optocoupler EL3063S(TA) (produced by Everlight). The load is connected in series with the thyristor control circuit. One end of the built-in zero-crossing optocoupler is connected to the live wire after connecting resistor R95, and the other end is commonly connected to resistor R47 and the control electrode of the thyristor. The photodiode of the built-in zero-crossing optocoupler is connected to a +5V current-limiting circuit and the control port of microcontroller BTA. The microcontroller outputs an electrical signal to make the built-in zero-crossing optocoupler conduct when the current passes through zero, thereby making the thyristor conduct and the load work.
[0017] Among them, the load can be components such as an electric heater, an LED lamp, a motor, etc.
[0018] The thyristor control circuit includes a thyristor BTA24-800B and its absorption circuit, and the absorption circuit is composed of a capacitor and resistor R99 in series. The absorption circuit is connected in parallel to the two ports of the thyristor BTA24-800B. One end of the capacitor is connected to resistor R99, and the other end is connected to the live wire. The other end of resistor R99 is commonly connected to resistor R47 and anti-interference inductor LL1, and the anti-interference inductor LL1 is connected to the load.
[0019] The +5V current-limiting circuit is composed of a pull-up resistor R93 and a current-limiting resistor R94. The common connection end of the pull-up resistor R93 and the current-limiting resistor R94 is connected to the +5V power supply, and the other end of the pull-up resistor R93 is connected to the photodiode and the control port of microcontroller BTA.
[0020] During operation, the microcontroller outputs a control electrical signal to the BTA control port. The photodiode inside the built-in zero-crossing optocoupler EL3063S(TA) (produced by Everlight) drives the built-in zero-crossing optocoupler EL3063S(TA) (produced by Everlight) to conduct when the mains current is overcurrent, thereby triggering the control electrode of the thyristor BTA24-800B, making the thyristor conduct when overcurrent, and enabling the load to be powered on and work. The microcontroller controls the working frequency of the load by controlling the output electrical signal.
[0021] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.
Claims
1. A low-cost and simple circuit with zero-crossing detection, characterized in that, It includes a load connected to the 220V mains circuit, a thyristor control circuit, and a built-in zero-crossing optocoupler. The load is connected in series with the thyristor control circuit. One end of the built-in zero-crossing optocoupler is connected to resistor R95 and then connected to the live wire, and the other end is commonly connected to resistor R47 and the control electrode of the thyristor. The photodiode of the built-in zero-crossing optocoupler is connected to the +5V current-limiting circuit and the control port of the single-chip microcomputer BTA. The single-chip microcomputer outputs an electrical signal to make the built-in zero-crossing optocoupler conduct when the current passes through zero, so that the thyristor conducts and the load works.
2. The low-cost and simple circuit with built-in zero-crossing detection according to claim 1, characterized in that, The load is an electric heater, or an LED lamp, or a motor.
3. The low-cost and simple circuit with zero-crossing detection according to claim 1, characterized in that, The thyristor control circuit includes a thyristor and its absorption circuit. The absorption circuit includes a capacitor and resistor R99 connected in series.
4. The low-cost and simple circuit with built-in zero-crossing detection according to claim 3, wherein, The absorption circuit is connected in parallel to the two ports of the thyristor. One end of the capacitor is connected to resistor R99, and the other end is connected to the live wire. The other end of resistor R99 is commonly connected to resistor R47 and anti-interference inductor LL1. The anti-interference inductor LL1 is connected to the load.
5. The low-cost and simple circuit with built-in zero-crossing detection according to claim 1, characterized in that, The +5V current-limiting circuit includes a pull-up resistor R93 and a current-limiting resistor R94. The common connection end of the pull-up resistor R93 and the current-limiting resistor R94 is connected to the +5V power supply. The other end of the pull-up resistor R93 is connected to the photodiode and the control port of the single-chip microcomputer BTA.