Low-power-consumption AC zero-crossing optical coupler device and zero-crossing detection architecture

Abstract

The utility model relates to a low-power-consumption AC zero-crossing optocoupler device, which comprises a photodiode, a phototriode and an integrated circuit, and is characterized in that the integrated circuit drives the photodiode to be conducted during AC zero crossing and transmits an AC zero-crossing instruction to the phototriode to output a zero-crossing signal ZEROout to a post-stage MCU control circuit or a CPU, so that the zero-crossing signal transmission and control work of a system is completed; and the photodiode is switched off when AC does not cross zero, so that the static power consumption of the system is reduced, and various energy efficiency regulation requirements are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor devices, in particular to a low-power AC zero-crossing optocoupler. BACKGROUND

[0002] In home appliances, communication and industrial control systems, silicon-controlled rectifiers are often used for heating control or motor speed control through phase-cutting, specified phase points of AC cycles are often used for switching inductive or capacitive loads, and AC zero-crossing points are often used to transmit power line carrier synchronization signals. These applications all require the system to provide an isolated AC zero-crossing signal to the backend control circuit CPU or MCU, which realizes the above control functions through this synchronization signal with the AC waveform. The zero-crossing signal is also often used in some electronic and electrical systems to determine whether the AC is disconnected. Figure 1 The traditional AC zero-crossing signal detection method is to connect a resistor (usually 100kΩ~220kΩ) in series with the photodiode side of the optocoupler to the AC end, thereby obtaining a zero-crossing signal synchronized with the AC sine voltage on the secondary side. The zero-crossing signal waveform is shown in Figure 3 However, this traditional method works throughout the AC cycle, resulting in power consumption, which increases the system's static power consumption and makes it difficult to meet the increasingly stringent electrical energy efficiency regulations.

[0003] Power consumption analysis of the traditional method:

[0004] In the traditional circuit, as shown in Figure 1 , the resistor is connected in series with the photodiode side of the optocoupler, and its power consumption can be calculated by the following formula:

[0005] Where:

[0006] PLOSS is the power consumption of the resistor;

[0007] VAC is the effective value of the AC voltage (usually 220V<China> or 240V<Europe>);

[0008] R is the resistance value of the series resistor (usually 100kΩ~220kΩ).

[0009] Taking 220V AC voltage and 100kΩ resistor as an example, its power consumption is:

[0010] P =220² / 100 = 0.484W

[0011] This means that the static power consumption of the resistor throughout the AC cycle is 0.484W. Even if a high-voltage diode D1 is used to isolate half of the AC cycle (as shown in the attached Figure 2As shown in the above table, the power consumption will also be as high as 0.242W, and for long-running devices, the cumulative power consumption will lead to a decrease in the overall energy efficiency of the device, and it will be difficult for the system to meet the latest energy efficiency regulations.

[0012] Energy efficiency regulations require:

[0013] For example, the EU-2023-826 energy efficiency directive requires that the static power consumption of household appliances and industrial control devices be significantly reduced, with specific standards as follows:

[0014] Standby power consumption is not more than 0.5W;

[0015] Power consumption is not more than 0.3W.

[0016] The traditional zero-crossing detection method as described above has high static power consumption, making it difficult for the system as a whole to meet the above requirements. SUMMARY

[0017] The purpose of the present application is to provide a low-power AC zero-crossing optocoupler to solve the problem of excessive static power consumption in the traditional method of using an optocoupler in series with a resistor for zero-crossing detection. By setting a control chip that detects AC state, the photodiode is only turned on for a very short time (e.g. 1ms) after AC zero-crossing, and remains off for most of the time (e.g. 19ms), thereby greatly reducing the power consumption of the circuit, and enabling the system to meet the latest energy efficiency regulations.

[0018] The low-power AC zero-crossing optocoupler provided in the present application employs the following technical solution:

[0019] A low-power AC zero-crossing optocoupler includes a photodiode, a photosensitive triode, and an integrated circuit. The integrated circuit drives the photodiode to conduct when AC is zero, transmits the AC zero-crossing command to the photosensitive triode to output a zero-crossing signal ZEROout to the subsequent MCU control circuit or CPU, and completes the zero-crossing signal transmission and control work of the system. When AC is not zero, the photodiode is disconnected, thereby reducing the static power consumption of the system and meeting various energy efficiency regulations.

[0020] Further, the integrated circuit is a control chip, and the control chip includes at least three functional pins, a voltage input PAD (vin), a drive PAD (drv), and a ground PAD (gnd).

[0021] Further, the control chip is preset to have a zero-crossing conduction duration of 0.01-10ms.

[0022] Further, the control chip has an AC cycle of 2.5ms-50ms, and a working voltage greater than 50Vac.

[0023] Furthermore, the photodiode, the phototransistor, and the control chip are integrated and packaged in the same package, and the package is in the form of DIP4 or SOP4, DIP6 or SOP6, or DIP8 or SOP8.

[0024] Furthermore, the package has two or more base islands, and the photodiode and the control chip are disposed on the same base island, while the phototransistor is disposed on another base island.

[0025] Furthermore, pin 1 of DIP4 or SOP4 is the positive terminal, pin 2 is the negative terminal, pin 3 is the reflector of the phototransistor, and pin 4 is the collector of the phototransistor.

[0026] Furthermore, pin 1 is internally connected to the voltage input PAD (vin) of the control chip, pin 2 is internally connected to the ground PAD (gnd) of the control chip and the cathode of the photodiode, and the drive PAD (drv) of the control chip is internally connected to the anode of the photodiode.

[0027] On the other hand, a zero-crossing detection architecture for a low-power AC zero-crossing optocoupler includes a series resistor and a high-voltage diode, wherein the resistor has a resistance value of 1kΩ to 3MΩ.

[0028] In summary, the aforementioned control chip and photodiode are encapsulated within the optocoupler, thus ensuring that the optocoupler remains compatible with existing pin configurations and electrical relationships. This allows for compatibility upgrades in existing application scenarios, or it can be packaged separately as an independent IC.

[0029] By adopting the above technical solutions, the system can achieve low-power zero-crossing detection, which facilitates rapid product upgrades. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a traditional optocoupler AC zero-crossing detection.

[0031] Figure 2 This is a schematic diagram of a traditional half-wave optical coupler AC zero-crossing detection.

[0032] Figure 3 for Figure 1 The zero-crossing signal waveform diagram.

[0033] Figure 4 This is a schematic diagram of zero-crossing detection for the low-power AC zero-crossing optocoupler of the present invention.

[0034] Figure 5 for Figure 4 The zero-crossing signal waveform diagram.

[0035] Figure 6 A plan view of the low-power AC zero-crossing optocoupler device of the present invention.

[0036] Figure 7 A package view of the low-power AC zero-crossing optocoupler device of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0038] It should be noted that the use of "one embodiment", "an embodiment", "example embodiment", etc. in the specification refers to the described embodiment including a particular feature, structure or characteristic, but not every embodiment necessarily includes the particular feature, structure or characteristic. In addition, such expressions do not refer to the same embodiment. Further, when a particular feature, structure or characteristic is described in connection with an embodiment, it is indicated that such a feature, structure or characteristic is incorporated into other embodiments within the knowledge of those skilled in the art, whether explicitly described or not.

[0039] In addition, some terms are used in the specification and subsequent claims to refer to specific components or parts, and those skilled in the art should understand that manufacturers can use different names or terms to refer to the same component or part. The specification and subsequent claims do not distinguish components or parts by name, but by functional differences. Throughout the specification and subsequent claims, "including" and "containing" are open terms, which should be interpreted as "including but not limited to". In addition, the term "connected" includes any direct and indirect electrical connection means. Indirect electrical connection means includes connection through other devices.

[0040] Specifically, the present application provides a low-power AC zero-crossing optocoupler device, an integrated circuit is sealed at the transmitting end of the traditional optocoupler. The integrated circuit can be designed as a control chip, which drives the optocoupler to conduct for a short time at each zero-crossing of the power grid AC, and controls the optocoupler to be turned off during the non-zero-crossing period of the power grid AC, thereby reducing the static power consumption of the system and meeting various energy efficiency regulations.

[0041] The control chip generates an internal power supply for powering the internal circuit, and also detects an AC zero-crossing signal, wherein the power supply and detection functions are always working, and the photodiode of the optocoupler is turned on at the moment of the AC zero-crossing, and the on duration can be set by the control chip, so as to transmit the AC zero-crossing instruction to the photosensitive triode on the secondary side, and the photosensitive triode outputs a zero-crossing signal ZEROout to the subsequent CPU or MCU control circuit, to complete the zero-crossing signal transmission and control work of the system, and the preset zero-crossing on duration of the control chip can be set to 0.01-10 ms, the application grid AC period can be 2.5 ms-50 ms, and the working voltage is greater than 50 Vac. For example, the preset zero-crossing on duration is 1 ms, and a short-time power consumption will be generated on the low-power AC zero-crossing optocoupler and the series resistor during this period, and during other time of the AC period, for example, 19 ms, the optocoupler and other modules of the control chip are kept in a disconnected state, and no power consumption or only a small static current (for example, 10 uA level) is generated; the above low-power AC zero-crossing optocoupler is responsible for providing isolation of the system, and the signal ZEROout synchronized with the grid AC zero-crossing point is obtained on the secondary side of the optocoupler and connected to the CPU or MCU control circuit, to complete the zero-crossing signal transmission and control work of the system. As can be seen, the control chip controls the optocoupler to be turned on only for a short time after the grid AC zero-crossing, so as to greatly reduce the static power consumption; the above control chip at least includes three functional pins, a voltage input PAD (vin), a driving PAD (drv) and a ground PAD (gnd).

[0042] Referring to Figure 4 and Figure 5 , it is a zero-crossing detection schematic diagram of the low-power AC zero-crossing optocoupler device and a waveform diagram of the zero-crossing signal ZEROout, and in this embodiment, the half-wave detection is still taken as an example, and the half-wave design can save cost and power consumption; based on the prior art Figure 2 , a control chip is arranged at the anode end of the photodiode of the optocoupler, the ground of the control chip is connected with the cathode of the photodiode, the input AC grid voltage 220 V and the frequency 50 Hz are input, that is, the AC period is 20 ms, and the static power consumption of the circuit is only generated when the optocoupler is turned on, and if the on time is set to 1 ms, the power consumption can be reduced to 1 / 20 of the original, and assuming that the resistance value is 100 kΩ, the average loss is:

[0043]

[0044] It can be calculated that the average power consumption is about 1.625 mW under 220 Vac and 50 Hz.

[0045] Compared with the traditional method, the power consumption is reduced by more than 99%, the zero-crossing circuit power consumption becomes a very small part of the system standby power consumption, and the system can therefore very conveniently realize the standby power consumption lower than the 0.3 W standby power consumption standard required by the EU-2023-826 energy efficiency directive.

[0046] Referring to Figure 6 and Figure 7 , the above control chip and the optocoupler are packaged in the same package to form the low-power AC zero-crossing optocoupler U11 of the present application, the zero-crossing detection and driving operation are completed in the optocoupler, and the user using the traditional zero-crossing detection mode can realize the low-power zero-crossing detection mode by simply replacing a low-power AC zero-crossing optocoupler, without changing other electronic components on the system PCB, and the traditional product can be easily upgraded.

[0047] Specifically, the frame of the package must be greater than or equal to two base islands, and the control chip and the photodiode of the optocoupler are arranged on the same base island, and the photosensitive triode on the secondary side is arranged on the other base island, and the two are packaged as a whole low-power AC zero-crossing optocoupler, the package can use DIP4 or SOP4 or DIP6 or SOP6 or DIP8 or SOP8 packaging form, and the external pins are compatible with the electrical characteristic relationship of the traditional optocoupler, to realize PCB compatibility.

[0048] Taking DIP4 or SOP4 as an example, the frame of the package has two base islands, the control chip and the photodiode are arranged on the same base island, and the photosensitive triode is arranged on the other base island, 1 pin is an electrical positive electrode, connected to the voltage input PAD (vin) of the control chip through a wire, and the 1 pin can be equivalent to the positive electrode of the photodiode in the traditional optocoupler; 2 pin is an electrical negative electrode, connected to the ground PAD (gnd) of the control chip through a wire, and connected to the cathode of the photodiode through conductive glue, and the 2 pin can be equivalent to the negative electrode of the photodiode in the traditional optocoupler; the driving PAD (drv) of the control chip is connected to the anode of the photodiode through a wire inside; 3 pin is the reflector of the photosensitive triode, and 4 pin is the collector of the photosensitive triode.

[0049] The technical features of the above embodiments can be combined in any way, and to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0050] The above embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as a limitation on the scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A low power AC zero-crossing optocoupler device, characterized by: The integrated circuit drives the photodiode to be turned on at AC zero crossing, transmits the AC zero crossing instruction to the phototriode to output the zero crossing signal ZEROout to the MCU control circuit or CPU in the next stage, and completes the zero crossing signal transmission and control work of the system; the photodiode is disconnected at AC non-zero crossing, thereby reducing the static power consumption of the system and meeting various energy efficiency regulations. The integrated circuit is a control chip, and the control chip contains at least three functional pins, a voltage input PAD (vin), a driving PAD (drv), and a ground PAD (gnd).

2. A low power consumption AC zero-crossing optocoupler device according to claim 1, characterized in that: The control chip presets the zero-crossing conduction duration as 0.01-10 ms.

3. A low power consumption AC zero-crossing optocoupler device according to claim 2, characterized in that: The working AC cycle of the control chip is 2.5 ms-50 ms, and the working voltage is greater than 50 Vac.

4. A low power consumption AC zero-crossing optocoupler device according to claim 3, characterized in that: The photodiode, the phototriode, and the control chip are integrated and packaged in the same package, and the package form of the package is DIP4 or SOP4, DIP6 or SOP6, DIP8 or SOP8.

5. A low power consumption AC zero-crossing opto-coupler device according to claim 2, characterized in that: The base island of the package is greater than or equal to 2, and the photodiode and the control chip are arranged on the same base island, and the phototriode is arranged on another base island.

6. A low power consumption AC zero-crossing optocoupler device according to claim 5, characterized in that: The 1 pin of the DIP4 or the SOP4 is the electrical positive electrode, the 2 pin is the electrical negative electrode, the 3 pin is the reflector of the phototriode, and the 4 pin is the collector of the phototriode.

7. A low power consumption AC zero crossing opto-coupler device according to claim 6, characterized in that: The 1 pin is connected to the voltage input PAD (vin) of the control chip, the 2 pin is connected to the ground PAD (gnd) of the control chip and the cathode of the photodiode, and the driving PAD (drv) of the control chip is connected to the anode of the photodiode.

8. A low power consumption AC zero-crossing optocoupler device according to claim 7, characterized in that: The resistance and the high-voltage diode are connected in series, and the resistance value is 1kΩ-3MΩ.

9. A zero-crossing detection architecture based on a low power AC zero-crossing optocoupler device according to any one of claims 1-8, characterized in that: ​

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