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US5270635A Expired / Lapsed US ⏱️ 0.0 years remaining

Universal battery charger

Assignee: Solid State Chargers Inc
•
Filing: 1992-02-14
•
Granted: 1993-12-14
•
Expires: 2012-02-14
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Abstract

Abstract A battery charger of the driven blocking oscillator type includes a three-winding transformer. The primary winding is connected in series with the collector-emitter path of a switching transistor. The secondary winding is connected in series with the collector-emitter path of a sense transistor which responds to the current flowing through the switching transistor. The tertiary winding is connected in series with the battery, series-connected batteries or series-connected battery packs sought to be recharged, via a diode, which may be connected in parallel with a capacitor. No smoothing capacitor is provided across the battery or batteries. The battery or batteries are charged by current pulses and discharge through the tertiary winding to repolarize the diode (and capacitor if present). The secondary winding is poled, with respect to the tertiary winding so that the blocking oscillator is driven by energy from the battery or batteries. The battery charger can operate over a wide range of input voltages with high efficiency, making it useful worldwide. The charger is effective to charge batteries and series connections thereof over a wide range of battery voltages. The charger will only function if at least one rechargeable battery is in circuit for charging. The charger may include circuitry for automatically taking substantially charged batteries or battery out of the charge path.

Inventors

  • 👤 Philip K. Hoffman
  • 👤 Douglas R. Frey

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 11:24
CPC Classifications
H; H02; H02J; H02J7/00; H02J7/02; H02J2207/00; H02J2207/20

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 121 words
A battery charger for charging a plurality of batteries defining part of a charging path and connected in series with a source of charging current, the charger comprising means for delivering charging current pulses to the plurality of batteries via the charging current path, and respective means responsive to respective terminal voltages of respective ones of the batteries for removing individual ones of the batteries from the charging current path whenever said individual ones of the batteries is or becomes substantially fully charged, wherein said means for delivering charging current pulses to the batteries includes a common transformer winding and respective diodes connected in series with respective ones of the batteries and respective capacitors connected in parallel with said respective diodes.
Claim 2
Dependent Claim 121 words
A battery charger for charging a plurality of batteries defining part of a charging path and connected in series with a source of charging current, the charger comprising means for delivering charging current pulses to the plurality of batteries via the charging current path, and respective means responsive to respective terminal voltages of respective ones of the batteries for removing individual ones of the batteries from the charging current path whenever said individual ones of the batteries is or becomes substantially fully charged, wherein said means for delivering charging current pulses to the batteries includes a common transformer winding and respective diodes connected in series with respective ones of the batteries and respective capacitors connected in parallel with said respective diodes.
Claim 3
Dependent Claim 18 words
The battery charger according to claim 1, wherein said means for delivering charging current comprises a blocking oscillator.
Claim 4
Dependent Claim 16 words
The battery charger according to claim 2, wherein said blocking oscillator is of the driven type.
Claim 5
Dependent Claim 20 words
the battery charger according to claim 1, wherein the circuits across the individual batteries are free of any smoothing capacitor.
Claim 6
Dependent Claim 112 words
A battery charger for charging a plurality of batteries defining part of a charging path and connected in series with a source of charging current, the charger comprising means for delivering charging current pulses to the plurality of batteries via the charging current path, and respective means responsive to respective terminal voltages of respective ones of the batteries for removing individual ones of the batteries from the charging current path whenever said individual ones of the batteries is or becomes substantially fully charged, and wherein said means for delivering charging current pulses to the batteries includes a common transformer winding and respective diodes connected in series with respective ones of the batteries.
Claim 7
Dependent Claim 112 words
A battery charger for charging a plurality of batteries defining part of a charging path and connected in series with a source of charging current, the charger comprising means for delivering charging current pulses to the plurality of batteries via the charging current path, and respective means responsive to respective terminal voltages of respective ones of the batteries for removing individual ones of the batteries from the charging current path whenever said individual ones of the batteries is or becomes substantially fully charged, and wherein said means for delivering charging current pulses to the batteries includes a common transformer winding and respective diodes connected in series with respective ones of the batteries.
Claim 8
Dependent Claim 18 words
The battery charger according to claim 5, wherein said means for delivering charging current comprises a blocking oscillator.
Claim 9
Dependent Claim 16 words
The battery charger according to claim 5, wherein said blocking oscillator is of the driven type.
Claim 10
Dependent Claim 20 words
The battery charger according to claim 5, wherein the circuits across the individual batteries are free of any smoothing capacitor.

References Cited (Backward Citations)

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US3673485A Cited
US4260943A Cited
US4423476A Cited
US4376263A Cited
US4523139A Cited
US4614905A Cited
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USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1996-12-13 1997-06-14 1997-12-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2000-12-13 2001-06-14 2001-12-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2004-12-13 2005-06-14 2005-12-14 $7700.00 Window Closed / Lapsed

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