Patent ID: 9270108
Filing Date: 2016-02-23
CPC Classification: H02H

Claim Text:
1. A protection circuit for a brushed DC motor, the protection circuit being connected between an AC power supply input and a rectifier circuit, the protection circuit functioning to stop the brushed DC motor under a given condition to protect the brushed DC motor, the protection circuit comprising: a) a power supply line; b) a power supply circuit, c) an AC detection circuit; d) a rectifier/filter voltage-stabilizing circuit; e) a microprocessor; f) a drive circuit; g) a switching unit; and h) a temperature detection circuit; wherein: the switching unit is connected to the power supply line in series; an input terminal of the power supply circuit is connected with the AC power supply input; an output terminal of the power supply circuit supplies power to the other circuits; the AC detection circuit detects a current in the power supply line; the current is processed by the rectifier/filter voltage-stabilizing circuit and sent to the microprocessor; an output terminal of the microprocessor is connected with an input terminal of the drive circuit; the drive circuit controls the switching unit to connect or disconnect the power supply circuit, wherein when the switching unit is disconnected from the power supply circuit, the brushed DC motor stops; the temperature detection circuit is connected to an input terminal of the microprocessor, and detects a working temperature of the brushed DC motor; the microprocessor controls the drive circuit to turn off the switching unit to stop the brushed DC motor, and to reduce the current to zero when the preset current value is independent from the working temperature of the brushed DC motor; and the preset current value is independent from the preset temperature value.