MOTOR DRIVING DEVICE AND MOTOR UNIT

A motor driving device includes an output circuit, a control circuit, a backflow preventing diode, and a capacitor. The output circuit is driven by a first voltage, includes a switching element of which turning-on/off is switched according to a switching control signal, and outputs current to motor coils when receiving a pulse-width-modulated first voltage. The control circuit is driven by a second voltage, and includes a position detecting circuit that detects the position of a rotor of the motor and a switching circuit that generates the switching control signal on the basis of the detection result of the position detecting circuit in order to switch the turning-on/off of the switching element. The capacitor performs a charging operation by a voltage applied from an input terminal of the first voltage through the diode, and applies a voltage of a node between the diode and the capacitor to the control circuit.