摘要 |
PURPOSE: A PWM(pulse width modulation) circuit for controlling PTC(positive temperature coefficient) heater of a vehicle is provided to reduce noise by connecting a line by-pass capacitor using a line to ground method. CONSTITUTION: A high voltage lead-in unit mounts a circuit component of a high voltage PWM ground. A low voltage lead-in unit controls a low voltage ground. The low voltage lead-in unit mounts a communication circuit component. An inductor and a noise filtering capacitor are arranged in the high voltage lead-in unit. Grounds of a circuit for controlling a high voltage PWM circuit component and other circuits are separated. [Reference numerals] (AA) High voltage; (BB) Low voltage |