A tightly regulated PWM-PFM-PD multiple output DC-DC converter

In this paper, a multiple output dc-dc converter is proposed. Pulse frequency modulation (PFM), pulse width modulation (PWM) and phase delay (PD) methods are used to regulate output voltages. Two of the output voltages are regulated by PWM, 2 of them by PFM, and the other one by PD. Five regulated outputs are obtained by using only two active switches. The switches can be operated at different switching frequencies. A hardware prototype was implemented that has 1.5V/0.5A, 3.3V/1A, 12V/0.5A, -12V/0.5A and 5V/1A outputs and the efficiency is 89% at the rated power.