BLOWER FAN CONTROLLER
BLOWER FAN CONTROLLER
SM2565454
id071100001500
Purpose
Function
Structure/Construction
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PWM (Pulse Width Modulation) circuit
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• The PWM circuit controls the blower motor rotation speed using pulse.• The PWM circuit decides duty ratio (pulse ON time) based on the signals from the climate control unit and turns the power MOS FET on/off at high speed.• When voltage of the threshold or more is applied to the gate, a large amount of electricity flows between the drain and source and the power MOS FET turns on.• The rotation of the blower motor is fast when the power MOS FET ON period is long (duty ratio is high), and it is slow when the period is short (duty ratio is low).• The PWM circuit performs duty control using the power MOS FET ON or OFF operation to reduce electric power loss and suppress heat generation in the circuit.
Operation