Electronic Circuits

Abstract

The present disclosure provides an electronic circuit, which relates to the field of circuits. The electronic circuit provided by the present disclosure includes a power supply circuit and a protection circuit; wherein the power supply circuit includes a power supply, a load, and a relay, and the power supply supplies power to the load when the relay is closed; the protection circuit is connected in parallel with the load, and the protection circuit forms a loop with the load when the relay is disconnected. By adding a protection circuit, the present disclosure can absorb the induced electromotive force generated by the load when the relay is turned off, thereby avoiding damage to the contacts caused by the impact of the induced electromotive force when the relay is turned off, thereby effectively protecting the contacts of the relay and improving the reliability and safety of the relay.

Description

Technical Field

[0001] The present disclosure relates to the field of circuits, and in particular to an electronic circuit. Background Art

[0002] With the development of technology in the circuit field, control systems have gradually put forward higher requirements on control quality, the integration of integrated circuits has gradually increased, and the number of low-voltage and low-power devices has gradually increased.

[0003] Using relays with passive contacts in circuits can improve the relays in terms of electromagnetic compatibility, circuit reliability, circuit safety, etc. Summary of the invention

[0004] A technical problem solved by the present disclosure is how to improve the reliability of relays.

[0005] According to one aspect of the present disclosure, an electronic circuit is provided, including a power supply circuit and a protection circuit; wherein the power supply circuit includes a power supply, a load and a relay, and the power supply supplies power to the load when the relay is closed; the protection circuit is connected in parallel with the load, and forms a loop with the load when the relay is disconnected.

[0006] In some embodiments, the protection circuit includes a DC protection circuit and an AC protection circuit; when the load is a DC load and the power supply is a DC power supply, the DC protection circuit is turned on and the AC protection circuit is turned off; when the load is an AC load and the power supply is an AC power supply, the AC protection circuit is turned on and the DC protection circuit is turned off.

[0007] In some embodiments, the protection circuit also includes a load detection element and a gating circuit, and the load detection element is configured to: detect whether the load is a DC load or an AC load; when it is detected that the load is a DC load, control the gating circuit to connect the DC protection circuit and disconnect the AC protection circuit; when it is detected that the load is an AC load, control the gating circuit to connect the AC protection circuit and disconnect the DC protection circuit.

[0008] In some embodiments, the load detection element includes an inductor and a first capacitor, and is configured to: determine that the load is a DC load when it is detected that the inductor forms a path; and determine that the load is an AC load when it is detected that the first capacitor forms a path.

[0009] In some embodiments, the DC protection circuit includes a varistor or a bidirectional transient voltage suppression diode, and the AC protection circuit includes a resistor and a second capacitor connected in series.

[0010] In some embodiments, the load is a DC load, the power supply is a DC power supply, and the protection circuit includes a varistor or a bidirectional transient voltage suppression diode.

[0011] In some embodiments, the load is an AC load, the power source is an AC power source, and the protection circuit includes a resistor and a second capacitor connected in series.

[0012] In some embodiments, the electronic circuit also includes a relay drive circuit; the relay drive circuit includes: a relay coil, configured to drive the relay to close or open by generating electromagnetic force; a relay control chip electrically connected to the first end of the relay coil; and a DC power supply electrically connected to the second end of the relay coil.

[0013] In some embodiments, the relay driving circuit further includes: a third capacitor connected in parallel with the relay coil; and a micro control unit electrically connected to the relay control chip.

[0014] In some embodiments, the relay is a relay of an air conditioning controller.

[0015] The present disclosure can absorb the induced electromotive force generated by the load when the relay is turned off by adding a protection circuit, thereby avoiding damage to the contacts caused by the impact of the induced electromotive force when the relay is turned off, thereby effectively protecting the contacts of the relay and improving the reliability and safety of the relay.

[0016] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or related technologies, the drawings required for use in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram showing the use of a relay to control the power supply to a load.

[0019] Figure 2 Circuit schematics of some embodiments of the electronic circuits of the present disclosure are shown.

[0020] Figure 3 Circuit schematics showing some embodiments of protection circuits in electronic circuits. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0022] Figure 1 A schematic diagram showing the use of a relay to control the power supply to a load. Figure 1 The relay uses passive contacts, L represents the live wire, N represents the neutral wire, and DO represents the connecting wire between the load and the relay.

[0023] The inventor has found that when a relay with passive contacts is used to control the power supply to a load, if there is an inductive device in the load, the load will generate a reverse induced electromotive force when the relay is disconnected, which will be applied to both ends of the passive contacts of the relay and cause an impact. When this reverse electromotive force is greater than the withstand voltage between the passive contacts of the relay, an arc will be generated between the passive contacts of the relay due to the high overvoltage. Once the relay is disconnected too many times, the passive contacts of the relay will be burned, causing damage to the relay and reducing the reliability of the relay.

[0024] In view of this, the present disclosure provides an electronic circuit that can improve the reliability of a relay. Figure 2 Some embodiments of the disclosed electronic circuits are described.

[0025] Figure 2 Schematic diagrams of some embodiments of the electronic circuits disclosed herein are shown. Figure 2 As shown, the electronic circuit includes a power supply circuit 21 and a protection circuit 22. The power supply circuit 21 includes a power supply 211, a load 212 and a relay 213. The power supply 211 supplies power to the load 212 when the relay 213 is closed; the protection circuit 22 is connected in parallel with the load 212, and the protection circuit 22 forms a loop with the load 212 when the relay 213 is disconnected.

[0026] This embodiment can absorb the induced electromotive force generated by the load when the relay is turned off by adding a protection circuit, thereby avoiding damage to the contacts caused by the impact of the induced electromotive force when the relay is turned off, thereby effectively protecting the contacts of the relay and improving the reliability and safety of the relay.

[0027] In addition, this embodiment has the characteristics of simple structure and strong practicality, and is suitable for application in scenarios with high requirements on relay reliability.

[0028] Combine the following Figure 3 The protection circuit is introduced in detail. Figure 3 The circuit diagrams of some embodiments of the protection circuit in the electronic circuit are shown. The setting of the protection circuit can specifically include three situations.

[0029] (I) Case 1: Only a DC protection circuit is provided.

[0030] If the load 212 is a DC load and the power supply 211 is a DC power supply, the protection circuit 22 includes a varistor RV or a bidirectional TVS (transient voltage suppression diode). For example, the protection circuit 22 can be a varistor RV, a bidirectional TVS, or a circuit composed of a varistor RV and a bidirectional TVS in series.

[0031] In the first case, when the relay 213 is disconnected, the DC induced electromotive force generated by the DC load forms a DC load loop through the RV or the bidirectional TVS, and consumes the electric energy in the protection circuit 22, thereby protecting the safety of the relay contacts and improving the reliability of the relay.

[0032] (ii) The second situation: only set up AC protection circuit.

[0033] If the load 212 is an AC load and the power source 211 is an AC power source, the protection circuit 22 includes a resistor R1 and a second capacitor C1 connected in series.

[0034] In the second case, when the relay 213 is disconnected, the AC induced electromotive force generated by the AC load forms an AC load circuit through DO, R1, and C1, and consumes electric energy in the protection circuit 22, thereby protecting the safety of the relay contacts and improving the reliability of the relay.

[0035] (III) The third situation: the DC protection circuit and the AC protection circuit are reused, and both the DC protection circuit and the AC protection circuit are set.

[0036] The protection circuit 22 includes a DC protection circuit 221 and an AC protection circuit 222. When the load 212 is a DC load and the power supply is a DC power supply, the DC protection circuit 221 is connected to form a DC load loop, and the AC protection circuit 222 is disconnected; when the load 212 is an AC load and the power supply 211 is an AC power supply, the AC protection circuit 222 is connected to form an AC load loop, and the DC protection circuit 221 is disconnected.

[0037] In some embodiments, the protection circuit 22 further includes a load detection element 223 and a gating circuit 224. The load detection element 223 is configured to: identify the DC point characteristics and AC characteristics of the load 212 to detect whether the load 212 is a DC load or an AC load. When it is detected that the load 212 is a DC load, the gating circuit is controlled to connect the DC protection circuit 221 and disconnect the AC protection circuit 222; when it is detected that the load 212 is an AC load, the gating circuit is controlled to connect the AC protection circuit 222 and disconnect the DC protection circuit 221. Those skilled in the art will understand that the DC protection circuit 221 may include a varistor or a bidirectional transient voltage suppression diode, and the AC protection circuit 222 may include a resistor R1 and a second capacitor C1 connected in series.

[0038] In some embodiments, the gating circuit may specifically include a single-pole double-throw switch, and the load detection element may include an inductor and a first capacitor. According to the characteristics of the inductor passing DC and blocking AC, and the characteristics of the capacitor passing AC and blocking DC, when it is detected that the inductor forms a path, it is determined that the load 212 is a DC load, and the DC protection circuit 221 is gated; when it is detected that the first capacitor forms a path, it is determined that the load 212 is an AC load, and the AC protection circuit 222 is gated.

[0039] The inventors took into account that the traditional relay protection circuit has poor versatility. When the type of load changes, the protection circuit needs to be modified and experimentally verified. Therefore, the development cycle is long and the development process is cumbersome, requiring a lot of manpower and material resources. In the third case, the electronic circuit reuses the protection circuit for absorbing the reverse electromotive force of the DC load and the protection circuit for absorbing the reverse electromotive force of the AC load at the same time, and can be flexibly switched according to demand. When the load is switched, the load detection module first identifies the load, and then selects the corresponding protection circuit to protect the relay. In this way, the electronic circuit provided in this embodiment can be applied to different types of loads and has good versatility. Therefore, the electronic circuit provided in this embodiment can also shorten the development process and development cycle in practical applications, saving the cost of electronic devices.

[0040] In some embodiments, the electronic circuit further includes a relay drive circuit 23. The relay drive circuit 23 includes: a relay coil 231, configured to drive the relay 213 to close or open by generating electromagnetic force; a relay control chip 232 electrically connected to a first end of the relay coil 231, configured to control the closing or opening of the relay 213; and a DC power supply 233 electrically connected to a second end of the relay coil 231, configured to supply power to the relay coil 231.

[0041] The control signal output by the relay control chip 232 generates a potential difference at both ends of the relay coil 231 and forms a current loop, thereby generating an electromagnetic force. Under the action of the electromagnetic force and the inherent elastic force of the relay reed, the passive contacts of the relay 213 are attracted or released, thereby connecting or disconnecting the loop composed of the load and the power supply.

[0042] In some embodiments, the relay drive circuit 23 also includes: a third capacitor 234 connected in parallel with the relay coil 231, configured to isolate the DC power supply 233 and the relay control chip 232; a micro control unit 235 electrically connected to the relay control chip 232, configured to control the relay control chip 232.

[0043] In some embodiments, the relay 213 is a relay of an air conditioner controller. Those skilled in the art will appreciate that the relay 213 may also be a relay of other electrical equipment, and the electronic circuit provided in the above embodiment may also be used to protect relays in other electrical equipment so as to absorb the reverse electromotive force generated by the inductive load in the circuit.

[0044] The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. An electronic circuit, comprising a power supply circuit and a protection circuit; wherein: The power supply circuit comprises a power supply, a load and a relay, wherein the power supply supplies power to the load when the relay is closed; The protection circuit is connected in parallel with the load, and the protection circuit forms a loop with the load when the relay is disconnected; The protection circuit includes a load detection element, a gating circuit, a DC protection circuit and an AC protection circuit, and the load detection element is configured as follows: Detecting whether the load is a DC load or an AC load; When it is detected that the load is a DC load, the gating circuit is controlled to connect the DC protection circuit and disconnect the AC protection circuit, wherein when the load is a DC load, the power supply is a DC power supply; When it is detected that the load is an AC load, the gating circuit is controlled to turn on the AC protection circuit and turn off the DC protection circuit, wherein when the load is an AC load, the power supply is an AC power supply.

2. The electronic circuit according to claim 1, wherein: The load detection element includes an inductor and a first capacitor, and is configured as follows: In the case where it is detected that the inductor forms a path, determining that the load is a DC load; When it is detected that the first capacitor forms a path, it is determined that the load is an AC load.

3. The electronic circuit according to claim 1, wherein: The DC protection circuit includes a varistor or a bidirectional transient voltage suppression diode, and the AC protection circuit includes a resistor and a second capacitor connected in series.

4. The electronic circuit according to claim 1, wherein: The load is a DC load, the power supply is a DC power supply, and the protection circuit includes a varistor or a bidirectional transient voltage suppression diode.

5. The electronic circuit according to claim 1, wherein: The load is an AC load, the power source is an AC power source, and the protection circuit includes a resistor and a second capacitor connected in series.

6. The electronic circuit according to any one of claims 1 to 5, further comprising a relay drive circuit; the relay drive circuit comprising: A relay coil, configured to drive the relay to close or open by generating electromagnetic force; a relay control chip electrically connected to the first end of the relay coil; A DC power source is electrically connected to the second end of the relay coil.

7. The electronic circuit according to claim 6, wherein: The relay drive circuit also includes: a third capacitor connected in parallel with the relay coil; A micro control unit electrically connected to the relay control chip.

8. The electronic circuit according to any one of claims 1 to 7, wherein: The relay is a relay of an air-conditioning controller.

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