Research And Design Of Dual Output DC/DC

Due to the miniaturization of computer device and other kinds of electronic product, the power system is required to be smaller, lighter and higher efficiency. And then, switching power supply, with its compact volume, small weight, high efficiency and excellent line regulation, has been widely applied in most of electronic fields.A dual output DC/DC converter is designed, one is BOOST which can generate a positive voltage; the other is BUCK/BOOST which can generate a negative voltage, both using the peak cuurent PWM control mode. The output voltage of the boost is internally fixed, where the output voltage of the BUCK/BOOST is fully configurable using external feedback resistors. The switching regulator operates at 1.75MHz. Cycle-by-cycle peak current limit, thermal shut down and undervoltage/overvoltage protection provide value added features to the stability and reliability of the device.In this paper, the global system architecture is proposed upon the design requirements and sub-module circuits are also analyzed and designed, including band-gap references,low-dropout voltage regulator,error amplifier,PWM comparator,oscillator with high frequency and narrow width pulse,current sense,slope compensation circuit,driver and several protection circuits, and so on. Finally, based on the Chrt 0.35μm CMOS process, the whole circuit is simulated by the EDA software Cadence spectre, whose results indicate performance have perfectly satisfied.