Controllable Power Supply Circuit for an Illumination System and Methods of Operation Thereof
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Abstract
A method for reducing acoustic noise produced during use of a lamp dimmer detects whether the dimmer is a leading edge (101) or a trailing edge dimmer (102). A nominal firing time of a leading edge dimmer is determined and a post-correction applied to a voltage applied to the dimmer starting from the nominal firing time so as to build-up the voltage gradually during a predetermined post-correction time period and thereby reduce the rate of rise of the leading edge thereof. A nominal cutoff time of a trailing edge dimmer is determined and a pre-correction applied to a voltage applied to the dimmer starting from the nominal cut-off time so as to diminish the voltage gradually during a predetermined pre-correction time period and thereby reduce the rate of rise of the leading edge thereof. Other methods are disclosed for soft starting filament lamps and controlling dimmer circuits.
45 Citations
38 Claims
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1-19. -19. (canceled)
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20. A method for reducing acoustic noise produced during use of a leading voltage edge dimmer so as to feed a controlled input voltage to an inverter coupled via bridge rectifier to the dimmer, the method comprising:
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(a) determining a maximum jitter angle Δ
t of a leading edge of the dimmer; and
(b) switching the inverter with a time delay larger than the maximum jitter angle Δ
t relative to a nominal firing angle t. - View Dependent Claims (21)
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22. A controller for feeding a controlled input voltage to an inverter coupled via bridge rectifier to a leading voltage edge dimmer, the controller being configured to:
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(a) determine a maximum jitter angle Δ
t of a leading edge of the dimmer; and
(b) switch the inverter with a time delay larger than the maximum jitter angle Δ
t relative to a nominal firing angle t. - View Dependent Claims (26)
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23. A method for reducing acoustic noise produced during use a trailing voltage edge dimmer so as to feed an input voltage to an inverter coupled via bridge rectifier to the dimmer, the method comprising:
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(a) determining a maximum jitter angle Δ
t of a leading edge of the dimmer; and
(b) switching the inverter with a time advance larger than the maximum jitter angle Δ
t relative to a nominal firing angle t. - View Dependent Claims (24)
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25. A controller for feeding a controlled input voltage to an inverter coupled via bridge rectifier to a trailing voltage edge dimmer, the controller being configured to:
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(a) determine a maximum jitter angle Δ
t of a leading edge of the dimmer; and
(b) switch the inverter with a time advance larger than the maximum jitter angle Δ
t relative to a nominal firing angle t.
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27. A method for soft starting a filament lamp, the method comprising:
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(a) during successive AC half cycles applying voltage slices starting from zero voltage;
(b) increasing the duration of said voltage slices during successive AC half cycles by controllable time increments (Δ
t1, Δ
t2 . . . Δ
tn);
(c) ensuring that a filament current flowing through a filament of the lamp does not exceed a predetermined threshold by;
i) comparing a pre-strike filament current corresponding to application of an instantaneous voltage slice prior to ignition of the filament lamp with a predetermined current threshold; and
ii) if the pre-strike filament current exceeds said threshold, maintaining the duration of a successive voltage slice to be equal to that of the instantaneous voltage slice. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. A method for reducing acoustic noise caused by a dimmer and allow for soft starting of filament lamps by controlled ignition of an inverter in a power supply circuit that has an input capacitance and that has a load coupled to an output of the inverter and in which an AC supply voltage is fed to the inverter via a dimmer circuit coupled to a bridge rectifier, the method comprising:
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(a) feeding rectified dimmer voltage to an input of the inverter;
(b) continually feeding ignition pulses to the inverter until a magnitude of the rectified dimmer voltage to an input of the inverter reaches a specific level; and
(c) when the magnitude of the rectified dimmer voltage fed to the input of the inverter reaches said specific level;
i) discharging the dimmer voltage across the input capacitance via the inverter to the load; and
ii) interrupting said ignition pulses to the inverter.
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38-1. An ignition circuit for igniting an inverter in a power supply circuit that has an in input capacitance and that has a load coupled to an output of the inverter and in which an AC supply voltage is fed to the inverter via a dimmer circuit coupled to a bridge rectifier, the ignition circuit being configured to:
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(a) feed rectified dimmer voltage to an input of the inverter;
(b) continually feed ignition pulses to the inverter until a magnitude of the rectified dimmer voltage to an input of the inverter reaches a specific level; and
(c) when the magnitude of the rectified dimmer voltage fed to the input of the inverter reaches said specific level;
i) discharge the dimmer voltage across the input capacitance via the inverter to the load; and
ii) interrupt said ignition pulses to the inverter.
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Specification