Current loop communication circuit and air conditioner

Abstract

The invention discloses a current loop communication circuit and an air conditioner and belongs to the technical field of electronic circuitry. The current loop communication circuit comprises first and second current loop communication circuits; the first current loop communication circuit includes a power supply circuit, a current loop communication control circuit and an overcurrent detection circuit; the power supply circuit includes a switching power supply transformer, a diode and an RC (resistor-capacitor) low-pass filter circuit; switching power is directly output by the diode after rectifying; power voltage is acquired through RC smooth filtering; the second current loop communication circuit includes a current loop control circuit and an overcurrent detection circuit; the opticalcoupling output end of the overcurrent detection circuit is connected with a controller to output a corresponding protective low level, thereby reminding a user of online line adapting errors. The current loop communication circuit that is low in cost helps solve the problem that electrical appliances, such as a variable frequency air conditioner, has low loss in communication; a warning functionfor mistaken line distributing is added, so that fault diagnosis and recording are provided i case of indoor and outdoor communication wiring errors.

Description

technical field [0001] The invention relates to the technical field of electronic circuits, in particular to a current loop communication circuit and an air conditioner. Background technique [0002] The current loop communication circuit is an interface circuit widely used in serial communication at present. Taking the communication of the inverter air conditioner as an example, at present, the indoor and outdoor communication of the inverter air conditioner generally adopts the direct resistance step-down method of the power supply system to provide communication power, see figure 1 As shown, the resistance direct step-down type is directly stepped down by the power supply voltage supplied by the system through the resistor R13, and the regulated power supply is provided by the voltage regulator diode ZD11, and the RC low-pass circuit is filtered. The step-down resistor R13 generates a lot of heat, and the circuit consumes high power. The power consumption is large, the c...

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Problems solved by technology

Taking the communication of the inverter air conditioner as an example, at present, the indoor and outdoor communication of the inverter air conditioner generally adopts the direct resistance step-down method of the power supply system to provide communication power, see figure 1 As shown, the resistance direct step-down type is directly stepped down by the power supply voltage supplied by the system through the resistor R13, and the regulated power supply is provided by the voltage regulator diode ZD11, and the RC low-pass circuit is filtered. The step-down resistor R13 generates a lot of heat, and the circuit consumes high power. Large power consumption, large current loop communication loss, and large drop-down resistor heating

For example, if the rated voltage of the design is in a 220Vac power supply, the same current loop communication circuit cannot be directly applied in a 110Vac power supply, and the relevant parameters need to be revised to achieve the application. The step-down circuit of the circuit loop has a large loss and cannot meet the requirements of low power consumption.

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