Ultra low power control circuits for PWM converters

Low voltage high-efficiency DC-DC conversion circuits are integral components of battery operated portable systems. This paper presents the design of a pulse width modulated (PWM) controller for a milliwatt level DC-DC converter. Low power control circuitry is constructed by utilizing a delay line based PWM generator and low-resolution feedback. A DC-DC converter has been fabricated which delivers 5 mW at 1 V, while achieving an efficiency of 88%. The PWM consumes only 10 /spl mu/W.