Lighting circuits, luminaries and methods compatible with phase-cut mains supplies
First Claim
1. A lighting circuit for mains LED lighting applications operable with a phase-cut dimmer, wherein the mains has a maximum voltage which is at least 200V, the circuit comprising:
- a rectifier having a low side output and a high side output;
a switched mode converter comprising a switch and an inductive element, having a high side input connected to a bus rail, and having a configuration so as to draw current from the mains across a complete mains cycle;
a controller for the switched mode converter;
a filter circuit connected between the rectifier high side output and the bus rail and comprising a capacitor connected between the high side output of the rectifier and ground;
a waveform shaping circuit arranged to provide a higher input current to the switched mode converter by increasing an on time of the switched mode converter when a momentary phase of the mains input signal exceeds 90°
; and
a combined damping/latch resistance connected between the low side output of the rectifier and ground.
1 Assignment
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Accused Products
Abstract
Lighting circuits and luminaires and methods are disclosed which are operable with a phase-cut dimmer, A circuit can include a rectifier having a low side output and a high side output, a switched mode converter including a switch and an inductor, having a high side input connected to a bus rail, and having a configuration to draw current across a complete mains cycle a controller for the switched mode converter, a filter circuit connected between the rectifier high side output and the bus rail and including a capacitor connected between the high side output of the mains rectifier and ground, and a resistance connected between the low side output of the rectifier and ground. The value of the resistance may be such the RC time constant of the resistor and filter circuit is greater than the time required for any ringing in the circuit to fall to no more than 20 mA.
11 Citations
16 Claims
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1. A lighting circuit for mains LED lighting applications operable with a phase-cut dimmer, wherein the mains has a maximum voltage which is at least 200V, the circuit comprising:
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a rectifier having a low side output and a high side output; a switched mode converter comprising a switch and an inductive element, having a high side input connected to a bus rail, and having a configuration so as to draw current from the mains across a complete mains cycle; a controller for the switched mode converter; a filter circuit connected between the rectifier high side output and the bus rail and comprising a capacitor connected between the high side output of the rectifier and ground; a waveform shaping circuit arranged to provide a higher input current to the switched mode converter by increasing an on time of the switched mode converter when a momentary phase of the mains input signal exceeds 90°
; anda combined damping/latch resistance connected between the low side output of the rectifier and ground. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification