Battery charging circuit
AssigneeBell Telephone Laboratories, Incorporated
InventorBarry Sheldon Bosik
Life of this patent
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Abstract
A single channel carrier system for telephone service is disclosed including at the remote terminal a battery charger for charging a battery which powers the carrier electronics at the remote terminal. A ringing generator and supervisory circuits are disclosed to provide normal telephone supervison on the carrier-derived channel. The battery charger includes a dc-to-dc converter to increase the rate of battery charging and an interface unit to minimize the effect on the telephone line by the charger. In one embodiment, the interface unit disconnects the charger to permit leakage testing of the line.
Claims10
A remotely powered battery charger comprising
- a switching signal generator,
- an energy storage type direct current converter driven by switching signals from said generator,
- a rechargeable battery connected to said converter, and
- a voltage breakdown device connected in parallel with said converter to charge said battery when said converter becomes inoperative.
A remotely powered telephone circuit comprising
- a battery,
- a battery charging circuit, and
- an interface circuit for connecting said battery charging circuit to a telephone line, said interface circuit comprising
- a detector circuit for detecting the voltage on said line,
- a switching circuit responsive to said detector for connecting said charging circuit to said line, and
- a delay circuit responsive to the application of a voltage to said line for delaying the operation of said switching circuit.
Dependencies are inferred from the claim text.