Variable valve timing controller for internal combustion engine

A variable valve timing controller adjusting a valve timing of an intake valve and/or an exhaust valve by varying a speed of an electric motor relative to a rotational speed of a camshaft in such a manner as to vary a rotational phase of the camshaft relative to a crankshaft of an internal combustion engine, variable valve timing controller comprising:

• a target motor speed calculating means for calculating a target motor speed based on a rotating speed of the internal combustion engine and a deviation between a target camshaft phase and an actual camshaft phase;
• a motor drive circuit which controls the driving current of the motor to decrease the deviation between the target motor speed and the actual motor speed;
• a voltage detecting means for detecting a supply voltage supplied to the motor drive circuit;
• and
• a motor current limit means for restricting an output current of the motor drive circuit when the supply voltage detected by the voltage detecting means is less than an operation limit voltage established higher than a minimum operation assurance voltage of the motor drive circuit.