The UCD8220 and UCD8620 are members of the UCD8K family of analog pulse-width modulator devices to be used in digitally managed power supplies using a microcontroller or the TMS320TM DSP family. UCD8220 and UCD8620 are double-ended PWM controllers configured with push-pull drive logic. The UCD8620 has a 110-V high-voltage startup circuit which can directly start up the controller from a 48-V telecom input line. Systems using UCD8K devices close the PWM feedback loop with traditional analog methods, but the UCD8K controllers include circuitry to interpret a time-domain digital pulse train. The pulse train contains the operating frequency and maximum duty cycle limit which are used to control the power supply operation. This eases implementation of a converter with high level control features without the added complexity or possible PWM resolution limitations of closing the control loop in the discrete time domain.