Apparatus and method for striking a fluorescent lamp
DCFirst Claim
Patent Images
1. A controller for an inverter that powers a fluorescent lamp, the controller comprising:
- a first input terminal configured to receive a voltage feedback signal indicative of an AC output voltage provided to the fluorescent lamp;
a second input terminal configured to receive a current feedback signal indicative of an AC lamp current conducted by the fluorescent lamp, wherein the fluorescent lamp is considered lit when a predetermined number of consecutive periodic cycles in the AC lamp current exceed a predefined amplitude and is otherwise considered unlit during a strike mode to ignite the fluorescent lamp;
an output terminal configured to provide a driving signal to a switching circuit that generates the AC output voltage from a DC input source;
a strike circuit configured to generate a timing signal based on the voltage feedback signal and the current feedback signal to control a frequency of the driving signal, wherein the timing signal varies the frequency of the driving signal to increase the AC output voltage when the voltage feedback signal indicates that the AC output voltage is less than a predefined striking level and the fluorescent lamp is considered unlit, holds the frequency of the driving signal at a substantially constant strike frequency associated with the AC output voltage reaching the predefined striking level while the fluorescent lamp is considered unlit, and shifts the frequency of the driving signal to a normal operating frequency that is different from the substantially constant strike frequency when the fluorescent lamp is considered lit; and
a driver circuit configured to generate the driving signal based at least in part on the timing signal.
5 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A lamp inverter with continuous strike voltage facilitates faster striking of a fluorescent lamp, especially at cold temperatures. A frequency sweep generator sweeps the frequency of the lamp inverter to a striking frequency corresponding to a striking lamp voltage and then maintains the striking frequency until the lamp strikes.
-
Citations
20 Claims
-
1. A controller for an inverter that powers a fluorescent lamp, the controller comprising:
-
a first input terminal configured to receive a voltage feedback signal indicative of an AC output voltage provided to the fluorescent lamp; a second input terminal configured to receive a current feedback signal indicative of an AC lamp current conducted by the fluorescent lamp, wherein the fluorescent lamp is considered lit when a predetermined number of consecutive periodic cycles in the AC lamp current exceed a predefined amplitude and is otherwise considered unlit during a strike mode to ignite the fluorescent lamp; an output terminal configured to provide a driving signal to a switching circuit that generates the AC output voltage from a DC input source; a strike circuit configured to generate a timing signal based on the voltage feedback signal and the current feedback signal to control a frequency of the driving signal, wherein the timing signal varies the frequency of the driving signal to increase the AC output voltage when the voltage feedback signal indicates that the AC output voltage is less than a predefined striking level and the fluorescent lamp is considered unlit, holds the frequency of the driving signal at a substantially constant strike frequency associated with the AC output voltage reaching the predefined striking level while the fluorescent lamp is considered unlit, and shifts the frequency of the driving signal to a normal operating frequency that is different from the substantially constant strike frequency when the fluorescent lamp is considered lit; and a driver circuit configured to generate the driving signal based at least in part on the timing signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. A method to control striking of a fluorescent lamp, the method comprising:
-
monitoring an AC output voltage across the fluorescent lamp; determining whether the fluorescent lamp is lit based on an AC lamp current conducted by the fluorescent lamp, wherein the fluorescent lamp is considered unlit when the AC lamp current is less than a predetermine amplitude and is considered lit when the AC lamp current exceeds the predetermine amplitude for a predetermined number of consecutive cycles; sweeping a frequency of a driving signal from an initial frequency to a striking frequency to increase the AC output voltage when the fluorescent lamp is unlit and the AC output voltage is less than a predefined level, wherein the AC output voltage has approximately the predefine level when the frequency of the driving signal is at the striking frequency; maintaining the frequency of the driving signal at the striking frequency until either the fluorescent lamp is considered lit or a time-out period expires; and changing the frequency of the driving signal from the strike frequency to a run frequency if the fluorescent lamp is considered lit, wherein the run frequency is different from striking frequency. - View Dependent Claims (15, 16, 17, 18)
-
-
19. An inverter controller comprising:
-
means for tracking an AC output voltage; means for tracking an AC output current; means for varying a frequency of a driving signal to increase the AC output voltage when the AC output voltage is less than a predefined level and the AC output current is less than a predefined amplitude; means for locking the frequency of the driving signal to a substantially constant locked frequency when the AC output voltage reaches the predefined level and the AC output current is less than the predefined amplitude; and means for changing the frequency of the driving signal from the substantially constant locked frequency to a normal operating frequency when the AC output current is greater than the predefined amplitude for at least a predetermined number of consecutive cycles, wherein the normal operating frequency is different from the substantially constant locked frequency. - View Dependent Claims (20)
-
Specification