Electrical circuit to reduce voltage supplied to sensitive components from elevated voltage supply of a vehicle battery
First Claim
1. In a vehicle having an engine, a transmission to be driven by the engine, an electrical generator to be driven by one of said engine and said transmission, and a battery to supply with said electrical generator electrical power at an output voltage which, under the control of a voltage regulator, varies from a nominal value with variation in ambient temperature, in accord with a substantially linear gradient,an electrical circuit comprising a first sub-circuit and a second sub-circuit,wherein said first sub-circuit includes said battery, said electrical generator and a plurality of first electrical components operably tolerant of supply voltages having an elevated value above said nominal value of the output voltage,said second sub-circuit includes at least one second electrical component that is operably intolerant of prolonged voltage supply at a said elevated value,and wherein said second sub-circuit is connected to the first sub-circuit(a) via a diode to provide a substantially constant voltage drop from the first sub-circuit to the second sub-circuit such as to provide the said at least one second electrical component with a consequential lower voltage that can vary with ambient temperature in accord with a gradient generally parallel to said substantially linear gradient, and(b) via switch means in parallel with the diode to provide, when closed, a direct current path from the first sub-circuit to the second sub-circuit.
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Accused Products
Abstract
An electrical circuit for a vehicle comprises a first branch or sub-circuit and at least one second branch or sub-circuit. The first branch or sub-circuit includes the vehicle battery, an electrical generator to be driven by the vehicle'"'"'s engine or transmission and for charging the battery, a starter motor to be driven by the battery for initiating engine operation, and a number of electrical components operable at voltages equal to or greater than the battery'"'"'s nominal output voltage. At least one of the second branches or sub-circuits includes a number of other electrical components (e.g. lamps) that are susceptible to damage if the voltage supply thereto is too high, this second branch or sub-circuit being connected to the first branch or sub-circuit via an element, e.g. a diode, providing a substantially constant voltage drop.
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Citations
13 Claims
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1. In a vehicle having an engine, a transmission to be driven by the engine, an electrical generator to be driven by one of said engine and said transmission, and a battery to supply with said electrical generator electrical power at an output voltage which, under the control of a voltage regulator, varies from a nominal value with variation in ambient temperature, in accord with a substantially linear gradient,
an electrical circuit comprising a first sub-circuit and a second sub-circuit, wherein said first sub-circuit includes said battery, said electrical generator and a plurality of first electrical components operably tolerant of supply voltages having an elevated value above said nominal value of the output voltage, said second sub-circuit includes at least one second electrical component that is operably intolerant of prolonged voltage supply at a said elevated value, and wherein said second sub-circuit is connected to the first sub-circuit (a) via a diode to provide a substantially constant voltage drop from the first sub-circuit to the second sub-circuit such as to provide the said at least one second electrical component with a consequential lower voltage that can vary with ambient temperature in accord with a gradient generally parallel to said substantially linear gradient, and (b) via switch means in parallel with the diode to provide, when closed, a direct current path from the first sub-circuit to the second sub-circuit.
Specification