Abstract: An anti-striation circuit employs an inverter topology including a pair of electronic switches (Q, M) that are switched between a conducting state and a nonconducting state in an alternating manner to apply an asymmetrical voltage waveform across one or more lamp (LP) to thereby control a flow of an asymmetrical current waveform (iacc) through lamps (LP). To eliminate, if not minimize, visible striations in the lamp(s) (LP), the impedances of an asymmetrical driver as connected to the control inputs (B, G) of the electronic switches (Q, M) may be unequal, and/or the impedances of an asymmetrical driver as connected to the current paths (C-E, D-S) of the electronic switches (Q, M) may be unequal. Additionally, the current gains of the electronic switches (Q, M) may be unequal, and a DC current may flow through the lamp(s) (LP).

Abstract: The power supply (20) for LEDs provides power to a LED light source (10) having a variable number of LEDs wired in series and/or in parallel. The power supply (20) uses current and voltage feedback to adjust power to the LEDs and provides protection to the LED light source (10). A feedback controller (27) compares sensed current and sensed voltage to a reference signal and generates a feedback signal, which is processed by a power factor corrector (124) to adjust the current flow through the transformer supplying current to the LEDs. A LED control switch (24) clamps a peak of the current to the LEDs to provide further protection to the LED light source (10). A short/open detection circuit (30) indicates any detection of a “LED outage” of the LED light source (10).

Abstract: The power supply (20) for LEDs provides power to a LED light source (10) having a variable number of LEDs wired in series and/or in parallel. The power supply (20) uses current and voltage feedback to adjust power to the LEDs and provides protection to the LED light source (10). A feedback controller (27) compares sensed current and sensed voltage to a reference signal and generates a feedback signal, which is processed by a power factor corrector (124) to adjust the current flow through the transformer supplying current to the LEDs. A LED control switch (24) clamps a peak of the current to the LEDs to provide further protection to the LED light source (10). A short/open detection circuit (30) indicates any detection of a “LED outage” of the LED light source (10).