Overvoltage protection device
First Claim
1. An overvoltage protection device for protecting the electrical system of a vehicle against overvoltages, the vehicle having an on-board wiring network connected to an electrical generator and having electrical devices connected thereto, said protection device comprising:
- controllable switching means for effectively short-circuiting the generator in case of an overvoltage condition, the switching means including a switching transistor means connected in parallel to the generator;
evaluation means, connected to receive the generator voltage, for issuing a first evaluation signal when a predetermined overvoltage threshold value is exceeded by the generator voltage and for issuing a second evaluation signal when the generator voltage subsequently falls below a predetermined low voltage threshold; and
memory means for receiving the evaluation signals and for controlling the switching transistor means, said memory means storing one of the received evaluation signals until receipt of the other evaluation signal, wherein during storage of the first evaluation signal, said memory means outputs a signal for controlling the switching transistor means to effectively short-circuit the generator and, during storage of the second evaluation signal, said memory means outputs a signal for controlling the switching transistor means to assume a switching condition not effectively short-circuiting the generator.
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Accused Products
Abstract
An overvoltage protection device for protecting the electrical system of a vehicle against overvoltages, the vehicle having an on-board wiring network connected to an electrical generator and having electrical devices connected thereto, includes a controllable switch for effectively short-circuiting the generator in case of an overvoltage condition. The switch includes a switching transistor connected in parallel to the generator. Evaluation circuitry connected to receive the generator voltage is provided for issuing a first evaluation signal when a predetermined overvoltage threshold is exceeded and for issuing a second evaluation signal when the generator voltage subsequently falls below a predetermined low voltage threshold. A memory is provided for receiving the evaluation signals and for controlling the switching transistor. The memory stores one of the received evaluation signals until receipt of the other evaluation signal. Furthermore, during storage of the first evaluation signal, the memory controls the switching transistor to effectively short-circuit the generator and during storage of the second evaluation signal, controls the switching transistor to assume a switching condition not effectively short-circuiting the generator.
27 Citations
14 Claims
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1. An overvoltage protection device for protecting the electrical system of a vehicle against overvoltages, the vehicle having an on-board wiring network connected to an electrical generator and having electrical devices connected thereto, said protection device comprising:
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controllable switching means for effectively short-circuiting the generator in case of an overvoltage condition, the switching means including a switching transistor means connected in parallel to the generator; evaluation means, connected to receive the generator voltage, for issuing a first evaluation signal when a predetermined overvoltage threshold value is exceeded by the generator voltage and for issuing a second evaluation signal when the generator voltage subsequently falls below a predetermined low voltage threshold; and memory means for receiving the evaluation signals and for controlling the switching transistor means, said memory means storing one of the received evaluation signals until receipt of the other evaluation signal, wherein during storage of the first evaluation signal, said memory means outputs a signal for controlling the switching transistor means to effectively short-circuit the generator and, during storage of the second evaluation signal, said memory means outputs a signal for controlling the switching transistor means to assume a switching condition not effectively short-circuiting the generator. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification