US3686530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Current limited battery pack
Assignee: Motorola Solutions Inc
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Filing: 1971-04-23
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Granted: 1972-08-22
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Expires: 1991-04-23
Abstract
Abstract A battery pack includes a resettable protection circuit for limiting the current to a load, which includes a normally nonconductive silicon controlled rectifier and a magnetic reed switch serially connected across a battery. When excessive load current develops, the silicon controlled rectifier is rendered conductive which in turn cuts off a regulating transistor or energizes a relay to prevent current flow to the load. The battery, magnetic reed switch, silicon controlled rectifier and regulating transistor or relay are encased in a sealed container to prevent sparks and arcing and allow usage in a hazardous atmosphere. The silicon controlled rectifier is reset, to allow continued usage of the battery, by actuating the reed switch with an externally supplied magnetic field. Actuation of the reed switch breaks the current path to the silicon controlled rectifier.
Inventors
- 👤 Henry A Bogut
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:16
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/02; H02H3/05; H02H3/08; H02H3/087
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
299 words
A protection circuit for terminating the current from a battery to a load in response to a load current in excess of a predetermined level, said protection circuit including in combination, first circuit means operative to couple said battery to said load for applying current thereto, second circuit means including a reed switch having a first normally closed position and a second magnetically actuated open position, a silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, a second reed switch having a first normally closed position and a second, magnetically actuated open position, a second silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, said second reed switch and second silicon controlled rectifier being coupled in parallel with said first reed switch and first silicon controlled rectifier, said second circuit means being coupled in parallel with at least a portion of said battery with said first reed switch and first silicon controlled rectifier, and said second reed switch and second silicon controlled rectifier forming series paths thereacross, and third circuit means coupled to said load and said first and second silicon controlled rectifier gate electrodes and operative in response to the load current exceeding said predetermined level to fire one of said first and second silicon controlled rectifiers allowing conduction therethrough, said first circuit means being coupled to said second circuit means and operative in response to conduction of one of said first and second silicon controlled rectifiers to terminate the current to said load, said first and second reed switches being operable to said second open position to open said second circuit means series paths and terminate conduction of said first and second silicon controlled rectifiers.
Claim 2
Dependent Claim
299 words
A protection circuit for terminating the current from a battery to a load in response to a load current in excess of a predetermined level, said protection circuit including in combination, first circuit means operative to couple said battery to said load for applying current thereto, second circuit means including a reed switch having a first normally closed position and a second magnetically actuated open position, a silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, a second reed switch having a first normally closed position and a second, magnetically actuated open position, a second silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, said second reed switch and second silicon controlled rectifier being coupled in parallel with said first reed switch and first silicon controlled rectifier, said second circuit means being coupled in parallel with at least a portion of said battery with said first reed switch and first silicon controlled rectifier, and said second reed switch and second silicon controlled rectifier forming series paths thereacross, and third circuit means coupled to said load and said first and second silicon controlled rectifier gate electrodes and operative in response to the load current exceeding said predetermined level to fire one of said first and second silicon controlled rectifiers allowing conduction therethrough, said first circuit means being coupled to said second circuit means and operative in response to conduction of one of said first and second silicon controlled rectifiers to terminate the current to said load, said first and second reed switches being operable to said second open position to open said second circuit means series paths and terminate conduction of said first and second silicon controlled rectifiers.
Claim 3
Dependent Claim
68 words
The protection circuit of claim 1 wherein said third circuit means includes resistance means coupled to said battery, to said load, and to said gate electrode, said resistance means developing a voltage thereacross in response to said load current which varies in accordance with the load current, said silicon controlled rectifier being operative in response to said voltage exceeding a predetermined level to fire and allow conduction therethrough.
Claim 4
Dependent Claim
53 words
The protection circuit of claim 2 wherein said first circuit means includes relay means, said relay means having means forming a closed circuit for coupling saiD load to said battery, said relay means being operative in response to conduction of said silicon controlled rectifier to open said circuit for terminating the load current.
Claim 5
Dependent Claim
54 words
The protection circuit of claim 3 wherein said relay means includes a normally closed contact thereon for coupling said load to said battery, and a relay actuation coil coupled to said second circuit means and responsive to conduction of said silicon controlled rectifier to energize and open said contact for terminating the load current.
Claim 6
Dependent Claim
47 words
The protection circuit of claim 2 wherein said first circuit means includes semiconductor means connecting said battery to said load, said semiconductor means being coupled to said switch means and operative in response to conduction of said silicon controlled rectifier for terminating the current to said load.
Claim 7
Dependent Claim
61 words
The protection circuit of claim 5 wherein said first circuit means includes a first transistor having base emitter and collector electrodes, said collector and emitter electrodes coupling said battery to said load and said base electrode being coupled to said switch means, said transistor operative in response to conduction of said silicon controlled rectifier for terminating the current to said load.
Claim 8
Dependent Claim
112 words
The protection circuit of claim 5 wherein said first circuit means includes a first transistor having a collector and emitter electrode for connecting said battery to said load, and a base electrode, a second transistor having a collector electrode coupled to said first transistor collector electrode, an emitter electrode coupled to said first transistor base electrode, and a base electrode coupled to said switch means, bias means coupled from said collector electrodes to said base electrode of said second transistor for rendering said transistors conductive to pass said load current, said first and second transistors operative in response to conduction of said silicon controlled rectifier for terminating the current to said load.
Claim 9
Dependent Claim
290 words
A battery pack for use in a battery operated device and including a protection circuit for terminating the current supplied to a load, said battery pack including in combination, a battery having a terminal for providing a potential of one polarity and a second terminal for providing a potential of opposite polarity, first circuit means operative to couple said battery to said load for applying current thereto, second circuit means including a reed switch having a first normally closed position for allowing conduction therethrough and a second magnetically actuated open position for inhibiting conduction therethrough, and a silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, said second circuit means being coupled in parallel with at least a portion of said battery with said reed switch and said silicon controlled rectifier first and second principal electrodes forming a series path thereacross, and third circuit means coupled to one of said battery terminals and to said silicon controlled rectifier and operative in response to the current to said load exceeding said predetermined level to fire said silicon controlled rectifier allowing conduction therethrough, said first circuit means being coupled to said reed switch and operative in response to conduction of said silicon controlled rectifier to terminate the current to said load, said reed switch being actuated by an externally supplied magnetic field and operative to open said series path and terminate conduction of said silicon controlled rectifier, and a housing for containing said battery and protection circuit, said housing having contacts thereon coupled to said battery terminals for coupling said battery terminals to said load and for charging said battery, said housing being sealed to isolate said battery and protection circuit.
Claim 10
Dependent Claim
290 words
A battery pack for use in a battery operated device and including a protection circuit for terminating the current supplied to a load, said battery pack including in combination, a battery having a terminal for providing a potential of one polarity and a second terminal for providing a potential of opposite polarity, first circuit means operative to couple said battery to said load for applying current thereto, second circuit means including a reed switch having a first normally closed position for allowing conduction therethrough and a second magnetically actuated open position for inhibiting conduction therethrough, and a silicon controlled rectifier having first and second principal electrodes coupled in series with said reed switch, and a gate electrode, said second circuit means being coupled in parallel with at least a portion of said battery with said reed switch and said silicon controlled rectifier first and second principal electrodes forming a series path thereacross, and third circuit means coupled to one of said battery terminals and to said silicon controlled rectifier and operative in response to the current to said load exceeding said predetermined level to fire said silicon controlled rectifier allowing conduction therethrough, said first circuit means being coupled to said reed switch and operative in response to conduction of said silicon controlled rectifier to terminate the current to said load, said reed switch being actuated by an externally supplied magnetic field and operative to open said series path and terminate conduction of said silicon controlled rectifier, and a housing for containing said battery and protection circuit, said housing having contacts thereon coupled to said battery terminals for coupling said battery terminals to said load and for charging said battery, said housing being sealed to isolate said battery and protection circuit.
Claim 11
Dependent Claim
72 words
The battery pack of claim 8 wherein said third circuit means includes resistance means serially coupled between one of said battery tErminals and said load, and to said gate electrode, said resistance means developing a voltage thereacross in response to said load current, said voltage varying in accordance with the load current, said silicon controlled rectifier operative in response to said voltage exceeding a predetermined value to fire and allow conduction therethrough.
Claim 12
Dependent Claim
171 words
The battery pack of claim 9 further including a second magnetically actuated reed switch and a second silicon controlled rectifier having first and second principal electrodes coupled in series with said second magnetically actuated reed switch, and a gate electrode, said second reed switch and said second silicon controlled rectifier coupled in parallel with at least a portion of said battery and said second reed switch and second silicon controlled rectifier forming a series path thereacross, said third circuit means being coupled to said second silicon controlled rectifier gate electrode and operative in response to the current to said load exceeding said predetermined level to fire said second silicon controlled rectifier allowing conduction therethrough, said first circuit means being coupled to said second reed switch and operative in response to conduction of said second silicon controlled rectifier to terminate the current to said load, said second reed switch being actuated to said second position by said externally applied magnetic field and operative to terminate conduction of said second silicon controlled rectifier.
Claim 13
Dependent Claim
82 words
The battery pack of claim 9 wherein said battery includes a plurality of cells coupled together, and said first circuit means includes a hermetically sealed relay, said relay having at least one normally closed contact for providing a conduction path between said cells and said load, said relay being operative in response to conduction of said silicon controlled rectifier to open said contact for breaking said conduction path and reducing the current supplied to said load by said battery pack to zero.
Claim 14
Dependent Claim
52 words
The battery pack of claim 9 wherein said first circuit means includes semiconductor means connecting one of said battery terminals to said load, said semiconductor means being coupled to said switch means and operative in response to conduction of said silicon controlled rectifier to limit the current to said load to zero.
Claim 15
Dependent Claim
66 words
The protection circuit of claim 12 wherein said first circuit means includes a first transistor having base emitter and collector electrodes, said collector and emitter electrodes coupling one of said battery terminals to said load and said base electrode being coupled to said switch means, said transistor operative in response to conduction of said silicon controlled rectifier to limit the current to said load to zero.
Claim 16
Dependent Claim
135 words
The battery pack of claim 12 wherein said first circuit means includes a first transistor having a collector and emitter electrode for connecting one of said battery terminals to said load, and a base electrode, a second transistor having a collector electrode coupled to said first transistor collector electrode, an emitter electrode coupled to said first transistor base electrode, and a base electrode coupled to said switch means, bias means coupled from said collector electrodes to said base electrode of said second transistor for rendering said transistors conductive to pass said load current, said first and second transistors operative in response to conduction of said silicon controlled rectifier to limit the current to said load, said bias means being further operative to limit the current from said battery when said silicon controlled rectifier is conductive.
Claim 17
Dependent Claim
56 words
The battery pack of claim 14 wherein said battery is a rechargeable battery, and further including a diode having an anode coupled to said emitter electrode of said first transistor and a cathode coupled to said collector electrode of said first transistor, said diode operative to allow charging of said battery from an externally connected charger.
Claim 18
Dependent Claim
33 words
The battery pack of cLaim 15 wherein said housing includes first and second sections sealed together to isolate said battery and protection circuitry, said first and second sections being formed from plastic material.
Claim 19
Dependent Claim
39 words
The battery pack of claim 12 wherein said battery is a rechargeable battery, and further including diode means coupled in parallel with said first circuit means and operative to allow charging of said battery from an externally connected charger.
References Cited (Backward Citations)
US3343060A
Cited
US3475653A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |