Patent ID: 7279874
Filing Date: 2007-10-09
Classification: H02M

Abstract:
1. A power supply device comprising: a PWM-controlled DC/DC converter capable of changing an output voltage on the basis of a setting signal, the DC/DC converter including a voltage change circuit configured to change a dead-time control voltage in accordance with a control signal and a dead-time control circuit which sets an upper limit value of an ON duty of a PWM main switching element at a predetermined time constant in accordance with the dead-time control voltage; and a control unit configured to output the setting signal instructing a change from a first voltage, which is presently being output, to a second voltage, and the control signal of a pulse width according to the first or second voltage; wherein said control unit outputs the control signal so as to set the upper limit value of the ON duty to a given value larger than a mean value of an ON duty corresponding to the first voltage and an ON duty corresponding to the second voltage.