LED outage detection circuit
AssigneeKoninklijke Philips Electronics N.V.
InventorJeroen Snelten
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Abstract
Disclosed is an outage detection circuit for detecting a defective light source, such as a LED coupled to a DC-DC converter circuit for receiving a power signal. The outage detection circuit includes a top voltage detector coupled to the LED for detecting a voltage across the LED. The top voltage detector has a top voltage terminal for supplying a top voltage signal. The detection circuit further includes a differential amplifier coupled to the top voltage terminal for receiving the top voltage signal as a first input signal and coupled to a reference voltage terminal. The reference voltage terminal is configured to supply a reference voltage as a second input signal. The differential amplifier includes an output terminal for supplying an outage detection signal.
Claims5
Outage detection circuit for detecting a defective LED, the LED being coupled to a DC-DC converter circuit for receiving a power signal, the outage detection circuit comprising:
- a top voltage detector coupled to the LED for detecting a voltage across the LED, the top voltage detector having an top voltage terminal for supplying a top voltage signal;
- and
- a differential amplifier coupled to the top voltage terminal for receiving the top voltage signal as a first input signal and coupled to a reference voltage terminal, the reference voltage terminal being configured to supply a reference voltage as a second input signal, the differential amplifier comprising an output terminal for supplying an outage detection signal, wherein the top voltage detector comprises a series connection of a diode and a capacitor and wherein the top voltage terminal is provided at a node between the diode and the capacitor.
Dependencies are inferred from the claim text.