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Fully digital parallel operated switch-mode power supply modules for telecommunications

Kutluay, Koray
Digitally-controlled, high power universal telecommunication power supply modules have been developed. In this work, the converter control strategy, and its design and implementation first, by means of parallel-operated, dual, 8-bit microcontrollers, and then by using a high processing power digital signal processor (DSP) have been emphasized. The proposed dual-processor based digital controller provides an extended operating output voltage range of the power supplies, user programmable current limit setting, serial communication based active load current sharing with automatic master-slave selection among parallel-operated modules, user selectable number of back-up battery cells, programmable temperature compensation curves, and automatic derating without extra hardware requirement. Overload and output short-circuit protection features are also controlled by software. One of the processors in the digital controller is employed for user interface purposes such as long term records, display, and alarm facilities, and remote control, which are inherently slow processes. The fast processing speed required by output voltage setting, current limit, and load current sharing however is to be fulfilled by a second processor dedicated to the adjustment of output voltages of modules. Tight dynamic load regulation requirement of a telecommunication power supply has been fulfilled by a 150 MIPS DSP, in place of a low cost, 8-bit microcontroller. The implemented digitally-controlled, 1.8 kW, 0-70V telecommunication power supplies have been tested successfully in several locations in the field.