Invention Grant
US09078328B2 Vehicle lighting outage detection circuit 有权
车辆停电检测电路

Vehicle lighting outage detection circuit
Abstract:
A vehicle lighting outage detection circuit is disclosed having a plurality of parallel branches connected at a common positive reference node. Each parallel branch comprises a branch resistor and a current controlled branch switching device connected in series. A constant current source is connected to the positive reference node and configured to deliver a substantially constant current to the positive reference node. The cathode of a zener diode is connected to the positive reference node. When current to a predetermined number of the branch resistors is interrupted due to the failure one or more LEDs connected to the control inputs of the branch switching devices, the voltage at the positive reference node increases beyond the breakdown voltage of the zener diode. In such a condition, excess current flow to the anode of the zener diode to supply an outage detection signal.
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