Universal and fault-tolerant multiphase digital PWM controller IC for high-frequency DC-DC converters

This paper describes a flexible 4-phase digital PWM controller IC that can be used with interleaved, multi-output, and parallel dc-dc switching converters operating at frequencies up to 10 MHz. The IC can be programmed to operate with any number of phases and it is fault-tolerant. If during interleaved mode a failure in one of the phases occurs, it automatically switches to operation with reduced number of phases by disabling the critical phase and adjusting the angles of the remaining ones. The key element of this IC is a new multi-phase digital-pulse width modulator (MDPWM) that utilizes a programmable counter, a delay line, and a digital logic with variable numbers representation. This IC is realized in a standard 0.18 mu m CMOS process and exhibits low power consumption of 45 mu A/MHz per phase. The controller operation is also experimentally verified with a 1 MHz, 25 W, 4-phase interleaved buck converter.