Intel Corporation
Fuse-less self-start controller

Abstract:

A digital self-start controller, which is functional without fuse and/or trim information. The self-start controller protects a DC-DC converter against large inrush currents and voltage overshoots, while being capable of following a variable VID (voltage identification) reference ramp imposed by the system. The self-start controller uses a relaxation oscillator to set the switching frequency of the DC-DC converter. The oscillator can be initialized using either a clock or current reference to be close to a desired operating frequency. The output of the DC-DC converter is coupled weakly to the oscillator to set the duty cycle for closed loop operation. The controller is naturally biased such that the output supply voltage is always slightly higher than a set point, eliminating the need for any process, voltage, and/or temperature (PVT) imposed trims.