Rejecting noise transients while turning off a fluorescent lamp using a starter unit

摘要

A local minimum of a current monitoring signal is identified by a starter unit that turns off a fluorescent lamp without using a wall switch. Closing a main switch in the starter unit stops an illuminating current from flowing through a gas in the lamp. The local minimum of the current monitoring signal is reached when an increasing valid sample is identified following four valid samples. A sample is valid if it does not differ from the preceding valid sample by more than a threshold difference based on known properties of the signal. By skipping invalid samples, the local minimum is accurately determined to have been reached despite transient noise spikes in the signal that would trip any voltage threshold used to locate the local minimum. When the main switch is opened at a predetermined time after the local minimum, the illuminating current does not again flow through the gas.

主权项

1. A method for operating a lamp, comprising:
(a) stopping an illuminating current from flowing through a gas of a lamp by closing a switch in a starter unit; (b) taking samples of a shunt current that flows through the switch when the switch is closed, wherein the samples of the shunt current are decreasing; and (c) opening the switch at a predetermined time interval after the samples of the shunt current first begin to increase after the samples of the shunt current are decreasing in (b).