Power supply for cellular communication stations

• US 5,731,693 A
• Filed: 10/23/1996
• Issued: 03/24/1998
• Est. Priority Date: 10/23/1996
• Status: Expired due to Fees

• Current Assignee: Eldec Corporation (Crane Company)
• Original Assignee: Eldec Corporation (Crane Company)
• Inventors: Furmanczyk, Kaz
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): HAN, YOUNGHUIE JESSICA
• Application Number:
  US08/735,779
• Time in Patent Office: 517 Days
• Field of Search: 323/265, 323/273, 323/274, 323/275, 323/276, 323/282, 323/284, 363/84, 363/124, 363/125, 307/45, 307/46, 307/64, 307/65, 307/66, 307/80, 307/82, 307/151
• US Class Current: 323/274
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 9/061 for DC powered loads

Abstract

An AC-to-DC converter and regulator normally receives power from an AC utility line and provides a stable DC output to a load, such as the power amplifier and transmitter of a cell site. The DC output, or a separate dedicated output from the converter, is used to charge a backup battery when AC power is available. If AC power is interrupted, the backup battery provides power to the load by way of a separate DC-to-DC differential converter. The battery is connected in parallel with the differential converter input, but in series with the differential converter output. Thus, the differential converter receives operating power from the battery, and outputs a voltage which is summed with the battery output to drive the load. A control circuit for the differential converter senses the voltage provided to the load, and supplies a signal to the differential converter to adjust its output as necessary to maintain the optimum aggregate output to the load.

Claims

1. In a system for supplying a DC voltage to a load, such system having an AC-to-DC converter, adapted to receive an AC line input, for normally supplying a regulated DC output to the load, and a backup system for supplying DC power to the load during AC power interruption, the improvement comprising the backup system including:

a backup battery producing a DC output voltage;

a differential DC-to-DC converter having a power input connected in parallel with the battery for receiving power therefrom and an output connected in series with the battery, the battery voltage and said differential DC-to-DC converter output supplying an aggregate voltage to the load;

a sensing circuit for measuring the aggregate voltage supplied to the load and for sending a control signal to the differential DC-to-DC converter, the differential DC-to-DC converter adjusting the voltage of its output based on the control signal for maintaining the aggregate output voltage at a predetermined value.

2. A system for providing a desired DC voltage to a load, comprising:

a battery producing a DC output voltage;

a differential converter coupled to the battery to receive power therefrom and producing a DC differential output voltage that is summed with the output voltage of the battery and provided to the load, the differential voltage varying based on a control signal received on a control input of the differential converter;

a feedback circuit coupled across the load and to the differential converter, the feedback circuit measuring a voltage applied to the load and producing said control signal that is applied to the control input of the differential converter to vary the differential voltage produced by the converter and maintain the voltage applied to the load at a desired level.