CN112071699A - Electronic circuit - Google Patents

Abstract

The present disclosure provides an electronic circuit, and relates to the field of circuits. The electronic circuit provided by the present disclosure includes a power supply circuit and a protection circuit; the power supply circuit comprises a power supply, a load and a relay, wherein the power supply supplies power to the load under the condition that the relay is closed; the protection circuit is connected with the load in parallel, and the protection circuit and the load form a loop under the condition that the relay is disconnected. This is disclosed through increasing protection circuit, can absorb the induced electromotive force that the load produced when the relay is turn-off, receives the impact of induced electromotive force to lead to the contact to damage when having avoided the relay to effectively protect the contact of relay, promote the reliability and the security of relay.

Description

electronic circuit

technical field

The present disclosure relates to the field of circuits, and in particular, to an electronic circuit.

Background technique

With the technological development in the field of circuits, the control system has gradually put forward higher requirements for control quality, the integration degree of integrated circuits has gradually increased, and the number of low-voltage and low-power devices has gradually increased.

Using relays with passive contacts in circuits can improve the electromagnetic compatibility, circuit reliability, and circuit safety of the relays.

SUMMARY OF THE INVENTION

One technical problem solved by the present disclosure is how to improve the reliability of the relay.

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 the protection The circuit forms a loop with the load with the relay open.

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 source is a DC power source, 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 source In the case of AC power supply, the AC protection circuit is connected and the DC protection circuit is disconnected.

In some embodiments, the protection circuit further includes a load detection element and a gating circuit, the load detection element is configured to: detect whether the load is a DC load or an AC load; and control the gating circuit to connect to a DC load when it is detected that the load is a DC load Connect the DC protection circuit and disconnect the AC protection circuit; in the case of detecting that the load is an AC load, control the gating circuit to connect the AC protection circuit and disconnect the DC protection circuit.

In some embodiments, the load detection element includes an inductance and a first capacitor, and is configured to: in the case of detecting that the inductance forms a path, determine that the load is a DC load; in the case of detecting that the first capacitor forms a path, determine the load for the AC load.

In some embodiments, the DC protection circuit includes a varistor or a bidirectional TVS diode, and the AC protection circuit includes a series-connected resistor and a second capacitor.

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

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.

In some embodiments, the electronic circuit further includes a relay drive circuit; the relay drive circuit includes: a relay coil configured to drive the relay to close or open by the generated electromagnetic force; a relay control electrically connected to the first end of the relay coil Chip; a DC power supply electrically connected to the second end of the relay coil.

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 with the relay control chip.

In some embodiments, the relay is a relay of an air conditioner controller.

By adding a protection circuit, the present disclosure can absorb the induced electromotive force generated by the load when the relay is turned off, and avoid the contact damage 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 of the relay. sex and safety.

Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present disclosure or related technologies more clearly, the following briefly introduces the accompanying drawings that are used in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only the For some of the disclosed embodiments, for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Figure 1 shows a schematic diagram of using a relay-controlled power supply to power a load.

FIG. 2 shows a circuit schematic diagram of some embodiments of the electronic circuit of the present disclosure.

Figure 3 shows a circuit schematic of some embodiments of a guard circuit in an electronic circuit.

Detailed ways

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application or uses in any way. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present disclosure.

Figure 1 shows a schematic diagram of using a relay-controlled power supply to power a load. In Figure 1, the relay adopts passive contact, L represents the live wire, N represents the neutral wire, and DO represents the connection line between the load and the relay.

The inventor's research found that when a relay with passive contacts is used to control the power supply to supply power to the load, if there is an inductive device in the load, the load will generate a reverse induced electromotive force when the relay is disconnected, thus adding to the passive power of the relay. both ends of the contacts and cause shock. When the back electromotive force is greater than the withstand voltage value between the passive contacts of the relay, an arc will be generated between the passive contacts of the relay due to the higher overvoltage. Once the relay is disconnected too many times, the passive contacts of the relay will be burned, resulting in damage to the relay and reducing the reliability of the relay.

In view of this, the present disclosure provides an electronic circuit that can improve the reliability of the relay. Some embodiments of the electronic circuits of the present disclosure are described below in conjunction with FIG. 2 .

FIG. 2 shows a circuit schematic diagram of some embodiments of the electronic circuit of the present disclosure. As shown in FIG. 2 , 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 is connected to the load when the relay 213 is disconnected. 212 forms a loop.

In this embodiment, by adding a protective circuit, the induced electromotive force generated by the load when the relay is turned off can be absorbed, so as to avoid the contact damage 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 of the relay. reliability and security.

In addition, this embodiment also has the characteristics of simple structure and strong practicability, and is suitable for application in a scenario that requires high reliability of the relay.

The protection circuit will be described in detail below with reference to FIG. 3 . Figure 3 shows a circuit schematic of some embodiments of a guard circuit in an electronic circuit. The setting of the protection circuit can specifically include three situations.

(1) The first case: only DC protection circuit is set.

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

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 bidirectional TVS, and consumes the electric energy on the protection circuit 22, thereby protecting the safety of the relay contacts and improving the relay. reliability.

(2) The second case: only the AC protection circuit is set.

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.

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 the electrical energy on the protection circuit 22, thereby protecting the safety of the relay contacts and improving the reliability of the relay.

(3) The third situation: multiplexing of the DC protection circuit and the AC protection circuit, setting both the DC protection circuit and the AC protection circuit.

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 source is a DC power source, 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 source 211 is an AC power source , the AC protection circuit 222 is connected to form an AC load loop, and the DC protection circuit 221 is disconnected.

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 characteristic and the AC current characteristic 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 switch on the DC protection circuit 221 and the AC protection circuit 222 is disconnected; when it is detected that the load 212 is an AC load, the gating circuit is controlled to switch on the AC protection Circuit 222, disconnect the DC protection circuit 221. Those skilled in the art can 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.

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 through DC, resisting the AC, and the characteristics of the capacitor passing through the AC and resisting the DC, when it is detected that the inductor forms a path, the load 212 is determined to be a DC load, and the DC protection circuit 221 is gated; when it is detected that the first capacitor forms a path In the case of , it is determined that the load 212 is an AC load, and the AC protection circuit 222 is gated.

The inventor considers 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 labor. material resources. In the third case, the electronic circuit multiplexes the protection circuit for absorbing the back electromotive force of the DC load and the protection circuit for absorbing the back electromotive force of the AC load at the same time, which can be flexibly switched according to requirements. 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, in practical applications, the electronic circuit provided in this embodiment can also shorten the development process and development cycle, and save the cost of electronic devices.

In some embodiments, the electronic circuit further includes a relay driver circuit 23 . The relay driving circuit 23 includes: a relay coil 231 configured to drive the relay 213 to close or open by the generated electromagnetic force; a relay control chip 232 electrically connected to the first end of the relay coil 231 and configured to close the relay 213 or disconnection for control; the DC power supply 233 electrically connected to the second end of the relay coil 231 is configured to supply power to the relay coil 231 .

Through the control signal output by the relay control chip 232, a potential difference is generated at both ends of the relay coil 231 to form a current loop, thereby generating electromagnetic force. Under the action of the electromagnetic force and the inherent elastic force of the relay reed, the passive contact of the relay 213 is pulled in or released, thereby connecting or disconnecting the circuit composed of the load and the power supply.

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

In some embodiments, relay 213 is a relay of an air conditioner controller. Those skilled in the art can understand that the relay 213 can also be a relay of other electrical equipment, and the electronic circuit provided by the above embodiment can also be used to protect the relay in other electrical equipment, so as to absorb the back electromotive force generated by the inductive load in the circuit.

The above descriptions are only preferred embodiments of the present disclosure, and are not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection of the present disclosure. within the range.

Claims (10)

1. An electronic circuit, comprising 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. 2. The electronic circuit according to claim 1, wherein the protection circuit comprises a DC protection circuit and an AC protection circuit; When the load is a DC load and the power source is a DC power source, 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 source is an AC power source, the AC protection circuit is turned on, and the DC protection circuit is turned off. 3. The electronic circuit of claim 2, wherein the guard circuit further comprises a load detection element and a gating circuit, the load detection element being configured to: Detecting whether the load is a DC load or an AC load; In the case of detecting that the load is a DC load, controlling the gating circuit to turn on the DC protection circuit and disconnect the AC protection circuit; When it is detected that the load is an AC load, the gating circuit is controlled to turn on the AC protection circuit and disconnect the DC protection circuit. 4. The electronic circuit of claim 3, wherein the load detection element includes an inductor and a first capacitor configured to: In the case of detecting that the inductance 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. 5. The electronic circuit of claim 2, wherein the DC protection circuit comprises a varistor or a bidirectional transient voltage suppression diode, and the AC protection circuit comprises a resistor and a second capacitor connected in series. 6. The electronic circuit of claim 1, wherein the load is a DC load, the power source is a DC power source, and the protection circuit comprises a varistor or a bidirectional transient voltage suppression diode. 7. The electronic circuit of claim 1, wherein the load is an AC load, the power source is an AC power source, and the protection circuit comprises a resistor and a second capacitor connected in series. 8. The electronic circuit according to any one of claims 1 to 7, further comprising a relay drive circuit; the relay drive circuit comprises: a relay coil configured to drive the relay to close or open by the generated 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. 9. The electronic circuit according to claim 8, wherein the relay driving circuit further comprises: a third capacitor connected in parallel with the relay coil; A micro-control unit electrically connected with the relay control chip. 10. The electronic circuit according to any one of claims 1 to 9, wherein the relay is a relay of an air conditioner controller.

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