Digital control of universal telecommunication power supplies using dual 8-bit microcontrollers

Design and implementation of a digital controller for universal telecommunication power supply modules are presented. The paper emphasises on converter control strategy, and its implementation by means of parallel operated, dual 8-bit microcontrollers. One of the microcontrollers is employed for user interface purposes, such as long term records, display and alarm facilities, which are inherently slow processes. The fast processing speed required by output voltage setting, current limit, and load current sharing however, is fulfilled by the second microcontroller, which adjusts the output voltages of modules. The proposed dual-processor based digital controller provides an extended operating output voltage range, user programmable current limit setting, serial-communication based active load current sharing between modules, and automatic derating without extra hardware requirement. Overload and output short-circuit protection features are also software-controlled. The controller is tested successfully on six parallel operating, 1.8 W, 0-70 V telecommunication power supplies.