BATTERY CHARGING CIRCUIT

• US 3,867,681 A
• Filed: 03/20/1974
• Issued: 02/18/1975
• Est. Priority Date: 03/20/1974
• Status: Expired due to Term

• Current Assignee: Larry D. Bishop, William R Smith
• Original Assignee: Larry D. Bishop, William R Smith
• Inventors: Bishop, Larry D., Smith, William R.
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/452,804
• Time in Patent Office: 335 Days
• Field of Search: 320/29-34,37,38,39,40,21,22,14,19
• US Class Current: 320/158
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H04M 19/06 in which current supply sources at subordinate switching centres are charged from the main exchange

Abstract

Batteries in locations such as unattended telephone buildings are kept in a good and reliable condition by a circuit which provides a normal charge periodically, which provides a normal charge each time the primary electrical power fails and is restored, and which provides an equalizing charge for a predetermined length of time in response to a manual or automatic operation.

Claims

1. An improved circuit for charging a battery from a charging source, comprising:

a. a voltage regulator adapted to be connected to the charging source, said voltage regulator having a control input for selectively causing said voltage regulator to produce an upper regulated voltage and a lower regulated voltage at its output;

b. a current regulator connected to said voltage regulator circuit;

c. a normally open charging path having an input connected to said current regulator, having an output, and having a control input;

d. means connected to said charging path output and adapted to be connected to the battery to be charged;

e. a voltage comparator having an input adapted to be connected to said battery to be charged for producing a first charging signal in response to a battery voltage below a selected voltage reference level;

f. a first timer for producing a second charging signal at selected predetermined intervals;

g. a power fail and restore circuit for producing a third charging signal in response to failure and subsequent restoral of primary power;

h. a second timer for producing a fourth charging signal of a selected duration in response to a selected operation;

i. means connected between said voltage comparator, said first timer, said power fail and restore circuit, and said second timer and between said charging path control input for closing said charging path in response to the simultaneous presence of said first charging signal and either of said second and third charging signals, and in response to said fourth charging signal;

j. and means connected between said second timer and said voltage regulator control input for causing said voltage regulator to produce said upper regulated voltage in the presence of said fourth charging signal and for causing said voltage regulator to produce said lower regulated voltage in the absence of said fourth charging signal.

2. The improved circuit of claim 1 wherein said selected voltage reference level varies inversely as a function of the ambient temperature surrounding said improved circuit.

3. The improved circuit of claim 1, and further comprising a latch circuit connected to said first timer and to said power fail and restore circuit for producing a continuous second charging signal and a continuous third charging signal in response to said second charging signal and said third charging signal respectively, and means connected between said voltage comparator and said latch circuit for disabling said latch circuit and stopping said second and third continuous charging signals in response to the absence of said first charging signal.

4. The improved circuit of claim 1, and further comprising means connected to said second timer for causing said second timer to produce said fourth charging signal in response to a battery discharge of selected duration.

5. The improved circuit of claim 1, and further comprising a latch circuit connected to said first timer and to said power fail and restore circuit for producing a continuous second charging signal and a continuous third charging signal in response to said second charging signal and said third charging signal respectively, means connected between said voltage comparator and said latch circuit for disabling said latch circuit and stopping said second and third continous charging signals in response to the absence of said first charging signal, and Means connected to said second timer for causing said second timer to produce said fourth charging signal in response to a battery discharge of selected duration.