Control circuit and device of power source of fresh keeping machine and control method thereof

Abstract

The invention discloses a control circuit and device of a power source of a fresh keeping machine and a control method thereof. The control method comprises the following steps: alternating current power input voltage is rectified by an input rectifying filter circuit and converted into direct current voltage; power output voltage is driven to be output by a driving circuit according to the direct current power input voltage; the power output voltage is detected by a voltage detection circuit, and a detection signal is output; the detection signal is read by a controller, and a control signal is output according to the amplitude of the detection signal; and the power output voltage is controlled to be output to a load by the output control circuit according to the control signal. The voltage detection circuit is arranged at a power output end, the output power and the output current of the power source of the fresh keeping machine can be limited, and the problems that the change of power voltage is large and the fresh keeping machine stands by for a long term are solved, so that the power source of the fresh keeping machine meets the requirements of the UL1310 CLASS TWO safety certificate. At the same time, the circuit and the device disclosed by the invention have simple and reliable structures, and the control method is simple and feasible.

Description

technical field [0001] The invention relates to the field of power supply technology, in particular to a fresh-keeping machine power supply control circuit, device and control method thereof. Background technique [0002] In the field of existing home appliances, many products use switching power supplies. The commonly used fresh-keeping machine switching power supply control circuit usually does not have a power feedback loop, and cannot effectively control the maximum output power. In the occasions where the circuit safety performance is very high, this method cannot meet the requirements of safety certification (such as UL1310 certification). [0003] In the prior art, the power supply control circuit of the fresh-keeping machine has the following technical problems: [0004] 1. The output power and output current cannot be controlled, and cannot meet the requirements of UL1310 CLASS TWO (CLASS TWO requires output power less than 100W and output current less than 8A). ...

AI Technical Summary

Problems solved by technology

[0004] 1. The output power and output current cannot be controlled, and cannot meet the requirements of UL1310 CLASS TWO (CLASS TWO requires output power less than 100W and output current less than 8A)

[0005] 2. When the power supply voltage changes greatly (more than +10%), the standby power may drift upward with time, and when the standby time is long, it will directly damage the power supply control circuit of the fresh-keeping machine and affect normal use

[0006] 3. When the output power is too stable, when the relay is directly connected to the load, it can work continuously for 7 hours without damaging the power control circuit, but it will burn out the power supply shell, which does not meet the UL1310 certification; when the output power is unstable, When the short-circuit relay is directly connected to the load, after ten to thirty minutes of continuous operation, the power supply control circuit of the fresh-keeping machine will continue to work or not work alternately. hours required

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