Controller device for variable valve timing apparatus

A controller device for a variable valve timing apparatus, the controller device applied to an internal combustion engine including the variable valve timing apparatus that changes a relative rotational phase of a camshaft with respect to a crankshaft of the internal combustion engine by adjusting a motor speed of a motor connected to the camshaft, the controller device comprising a controller unit that controls the variable valve timing apparatus,

• wherein during engine stop processing of the internal combustion engine, the controller unit performs a normal control of adjusting a current or a voltage supplied to the motor according to a rotational speed of the crankshaft to change the relative rotational phase of the camshaft to a most advanced position or a most retarded position when the rotational speed of the crankshaft is equal to or higher than a first threshold, a low-speed control of fixing the current or the voltage supplied to the motor to be constant to maintain the relative rotational phase of the camshaft at the most advanced position or the most retarded position during a period from when the rotational speed of the crankshaft becomes lower than the first threshold to when the rotational speed becomes zero,
• wherein the variable valve timing apparatus includes a motor driver that supplies the current or the voltage to the motor on a basis of a pulse width modulation (PWM) signal having an instruction pulse to drive the motor, and
• wherein the controller unit outputs a PWM signal having a duty ratio proportional to the rotational speed of the crankshaft to the motor driver in the normal control, and outputs a PWM signal having a fixed duty ratio fixed to a constant value to the motor driver in the low-speed control.