Modeling and Simulation of on-chip ramp generator for power management IC's using cadence

DC-DC converters are widely used in many applications and are most popular in electronic industry. In this paper we have designed an on chip ramp generator for power management IC that could be used in DC-DC Buck converter for controlling the duty cycle oexf the pulse width modulated signal. The on-ramp generator is implemented using the current charging and discharging circuit and comparator. The DC-DC Buck converter circuit is designed for an output voltage of 1.2V at a switching frequency of 1 MHz for variable input voltage from 3V to 8V. The effects of input voltage variation, load variation are handled by the feedback network and On-chip ramp generator circuit. The Design Modeling and simulation of closed loop buck converter is carried out using cadence tool with 180nm technology.