Comparison of power supplies for residential telephony systems

With the advent of broadband access products, many manufacturers are controlling and powering small phone systems. Numerous companies have developed high voltage subscriber line interface circuits (SLIC), which control the ring and voice transmission for these phone systems. This paper presents a comparison of approaches to providing high voltage power to these integrated solutions. Three approaches are presented; a low power residential application, a higher power residential application and a single line ring generator which removes functions off the SLIC and transfers it into the DC-AC inverter. Schematics and physical designs are discussed and efficiency, size and performance for these approaches are presented. Finally, recommendations are made for circuit configurations based on the key system requirements.