Emergency lighting circuit for shunt-regulated battery charging and lamp operation
First Claim
1. In a circuit including a first load operated on AC power and having a battery for providing current to a second load on discontinuation of AC power, the circuit being useful for charging the battery or a cell of the battery, comprising:
- at least one current limited charging means for providing a source of charging current to the battery and for supplying current to the first load;
means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for providing a low impedance circuit path, the low impedance circuit path not including the battery on termination of charging of the battery.
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Accused Products
Abstract
Battery charging circuits configured as a combination of current limited charging sources and a shunt regulating path to bypass current from a battery charging path through a low impedance path so that charge current can be regulated and terminated or controlled, the invention further includes combination of the circuits in emergency lighting systems utilizing conventional AC mains power in a non-emergency mode and DC battery power in an emergency mode, the battery being charged with regulation of charge current effected by said circuits when in the non-emergency mode. In the present circuits, current is by-passed from that portion of the circuit used for battery charging by provision of a low impedance alternate path through which current may also be supplied to non-emergency lamps, the alternate path supplanting prior art circuits which function by continuously turning a single path on and off for charge regulation. In primary embodiments, the circuits use the charging path to also drive the non-emergency lamps. Current through the alternate shunt regulating path drives the non-emergency lamps in the normal non-emergency mode without passing of the current through the battery.
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Citations
45 Claims
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1. In a circuit including a first load operated on AC power and having a battery for providing current to a second load on discontinuation of AC power, the circuit being useful for charging the battery or a cell of the battery, comprising:
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at least one current limited charging means for providing a source of charging current to the battery and for supplying current to the first load; means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for providing a low impedance circuit path, the low impedance circuit path not including the battery on termination of charging of the battery. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A circuit useful for charging at least one battery or a cell of a battery, comprising:
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at least one current limited charging means for providing a source of charging current; power conversion means for converting the charging current to a higher level current to charge the battery more rapidly; means for passing the higher level current through the battery to charge the battery; and
,shunt regulated switch means for passing current through a low impedance path of the circuit which does not include the battery on termination of charging of the battery. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A circuit useful for charging at least one battery, comprising:
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a current limited current source; a series device having a polarity dependent switch function; a shunt switch comprising a programmable unijunction transistor for providing charge control, the switch passing current through a low impedance path not inclusive of the battery on termination of charging of the battery; and
,means for controlling the shunt switch in response to battery voltage level. - View Dependent Claims (34, 35)
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36. A circuit useful for charging at least one battery or a cell of a battery, comprising:
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at least one current limited charging means for providing a source of charging current; means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for passing current through a low impedance path of the circuit which does not include the battery on termination of charging of the battery, the switch means comprising a programmable unijunction transistor. - View Dependent Claims (37)
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38. A circuit useful for charging at least one battery or a cell of a battery, comprising:
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at least one current limited charging means for providing a source of charging current; means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for passing current through a low impedance path of the circuit which does not include the battery on termination of charging of the battery, the switch means comprising a field effect transistor. - View Dependent Claims (39)
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40. A circuit useful for charging at least one battery or a cell of a battery, comprising:
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at least one current limited charging means for providing a source of charging current; means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for passing current through a low impedance path of the circuit which does not include the battery on termination of charging of the battery, the switch means comprising a voltage dependent switch. - View Dependent Claims (41, 42)
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43. In an emergency lighting system having a battery used for providing current in an emergency mode, a circuit useful for charging the battery, comprising:
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at least one current limited charging means for providing a source of charging current; means for passing charging current through the battery to charge the battery; and
,shunt regulated switch means for passing current through a low impedance path of the circuit which does not include the battery on termination of charging of the battery, the switch means being selected from the group consisting of a programmable unijunction transistor, a field effect transistor, a silicon controlled rectifier and a voltage dependent switch. - View Dependent Claims (44, 45)
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Specification