Lighting device with circuit and method for detecting power converter activity

摘要

A lighting device such as an electronic ballast or LED driver includes circuitry to detect power converter activity and act accordingly. A power factor correction (PFC) circuit includes an inductor, a power converter switch, and a PFC controller effective to provide driving signals the power converter switch to turn on and off. A power converter activity detection circuit includes a first capacitor coupled between the PFC controller and the power converter switch, a zener diode, and a second capacitor coupled between the first capacitor and ground. An output voltage for the power converter activity detection circuit as referenced from a node between the first capacitor and the second capacitor is representative of activity by the power converter switch, and is provided to a lighting device controller which may accordingly maintain operation of the lighting device where a mains power interruption is only temporary but would otherwise disable the device.

主权项

1. A lighting device comprising:
a power factor correction (PFC) circuit comprising an inductor, a power converter switch, and a PFC controller effective to provide driving signals for causing the power converter switch to turn on and off; a power converter activity detection circuit comprising
a first capacitor coupled on a first end to a node between the PFC controller and the power converter switch,a diode having an anode coupled to ground and a cathode coupled to a second end of the first capacitor, anda second capacitor coupled on a first end to the second end of the first capacitor and on a second end to ground; and wherein an output voltage for the power converter activity detection circuit referenced from a node between the first capacitor and the second capacitor is responsive to activity by the power converter switch.