LED driver circuits and methods
AssigneeMicrel, Inc.
InventorSteven Chenetz
Life of this patent
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Abstract
An LED driver circuit may include dimming circuitry. In particular, the LED driver circuit may include a switching converter, an LED and a switch. The LED may be electrically connected to the switching converter and the switch may be connected in parallel with the LED. The switching converter and/or the switch may be configured to be controlled to achieve dimming of the LED. Current may be supplied to the LED and the switch may be turned on and off to dim the LED. The switching converter coupled to the LED may include a switching element in series with an inductor and the LED. In such case, the switching element may be turned on to supply current to the LED and the inductor, and the switch may be turned on and off to dim the LED.
Claims21
An LED driver circuit, comprising:
- a switching converter having a duty cycle;
- a diode coupled to the switching converter for periodically passing current based on the duty cycle of the switching converter;
- an LED electrically connected to the switching converter;
- and
- a switch connected in parallel with the LED and the diode.
An LED driver circuit, comprising:
- a switching converter;
- an LED electrically connected to the switching converter, the switching converter including a switching element and an inductor connected in series with the LED and a diode connected in parallel with the LED and the inductor;
- and
- a switch connected in parallel with the LED.
A method of dimming an LED with a switch connected in parallel with the LED and a diode connected in parallel with the LED and the switch and a switching converter connected in series with the LED and having a duty cycle, comprising:
- supplying current to the LED via the diode according to the duty cycle of the switching converter;
- and
- turning the switch on and off to dim the LED.
A method of driving an LED with a switching converter coupled to the LED including a switching element in series with an inductor and the LED and with a switch connected in parallel with the LED, comprising:
- turning the switching element on to supply current to the LED and the inductor;
- and
- turning the switch on and off to dim the LED.
Dependencies are inferred from the claim text.