Light driving system and method
First Claim
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1. A light driving system comprising:
- a light dimmer that receives an AC input signal and provides a dimmer output signal that includes a fast rising leading edge;
a rectifier that receives the dimmer output signal and provide a rectified dimmer output signal;
an AC/ DC converter that filters the rectified dimmer output signal to provide a DC input signal that is employed to drive a light; and
a protection circuit that limits current to the AC/ DC converter during the fast rising leading edge of the dimmer output signal, wherein a controller opens the switch at a falling edge zero crossing point of the dimmer output signal, monitors for the fast rising leading edge of the dimmer output signal and closes the switch bypassing the protection element after a predetermined amount of time after the fast rising leading edge of the dimmer output signal is detected to allow sufficient energy dissipation to mitigate ringing caused by the fast rising leading edge.
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Abstract
A light driving system is provided that includes a light dimmer that receives an AC input signal and provides a dimmer output signal that includes a fast rising leading edge, a rectifier that receives the dimmer output signal and provide a rectified dimmer output signal and an AC/DC converter that filters the rectified dimmer output signal to provide a DC input signal that is employed to drive a light. The light driving system also comprises a protection circuit that limits current to the AC/DC converter during the fast rising leading edge of the dimmer output signal.
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Citations
14 Claims
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1. A light driving system comprising:
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a light dimmer that receives an AC input signal and provides a dimmer output signal that includes a fast rising leading edge; a rectifier that receives the dimmer output signal and provide a rectified dimmer output signal; an AC/ DC converter that filters the rectified dimmer output signal to provide a DC input signal that is employed to drive a light; and a protection circuit that limits current to the AC/ DC converter during the fast rising leading edge of the dimmer output signal, wherein a controller opens the switch at a falling edge zero crossing point of the dimmer output signal, monitors for the fast rising leading edge of the dimmer output signal and closes the switch bypassing the protection element after a predetermined amount of time after the fast rising leading edge of the dimmer output signal is detected to allow sufficient energy dissipation to mitigate ringing caused by the fast rising leading edge. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A light driving system comprising:
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a light dimmer that receives an AC input signal and provides a dimmer output signal that includes a fast rising leading edge; a rectifier that receives the dimmer output signal and provide a rectified dimmer output signal; an electromagnetic interference (EMI) filter coupled between the light dimmer and the rectifier to mitigate EMI; a switching converter that filters the rectified dimmer output signal to provide a DC input signal to a controller that controls a light driver to drive a light; and a protection circuit that limits current to the switching converter during the fast rising leading edge of the dimmer output signal, wherein the controller opens the switch at a falling edge zero crossing point of the dimmer output signal, monitors for the fast rising leading edge of the dimmer output signal and closes the switch bypassing the resistor after a predetermined amount of time after the fast rising leading edge of the dimmer output signal has been detected to allow sufficient energy dissipation to mitigate ringing caused by the fast rising leading edge. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method for suppressing ringing in a light driving system having an AC/ DC converter that drives a light, the method comprising:
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switching in a protection element into the light driving system to provide damping to protect the AC/ DC converter during a fast rising leading edge of an input signal; switching out the protection element after the fast rising leading edge of the input signal; switching in the protection element into the light driving system during startup to protect the AC/ DC converter from inrush current; and switching out the protection element after the voltage to the AC/ DC converter has reached a predetermined voltage, wherein the switching in the protection element into the light driving system comprises switching in a protection resistor at a falling edge zero crossing point of a dimmer output signal and the switching out the protection element after the fast rising leading edge comprises switching out the protection resistor after a predetermined amount of time to allow sufficient energy dissipation to mitigate ringing caused by the fast rising leading edge.
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Specification