48v communication base station power supply

The short story is that –48 V DC, also known as a positive-ground system, was selected because it provides enough power to support a telecom signal but is safer for the human body while doing telecom activities.

The -48V back-up battery converter is similar in construction and complexity to the single-output, high-power VoIP converter previously discussed. The power factor corrected (PFC) AC/DC produces the supply voltage for the 3G Base station's RF Power amplifier (typ. +27V) and the bus voltage for point-of-load converters.

In a DSL application, a -48V to multiple output converter may be used which incorporates a more complex, lower power transformer (50-100W) with several outputs.

This article presents a scalable and stackable –48 V DC PoL solution that will address the high density power usage situations created by these high density networks from the tremendous growth in network traffic. Telecom and wireless network systems typically operate on –48 V DC power.

However, the –48 V DC must first be efficiently converted to a positive intermediate bus voltage before it can be boosted to power the PA or stepped down to a positive workable supply for the digital baseband units (BBU). A power supply with a capacity of 100 W to 350 W was sufficient to cover many applications.

A simplified diagram of a typical telecommunications DC power system. When power from the grid is lost, the diesel generator is designed to start automatically providing AC power to the DC port system. The ATS synchronizes voltages from different sources to the equipment.