US 2008/0074348 A1 · LIGHT-EMITTING APPARATUS AND DRIVING CIRCUIT THEREOF

Abstract

An apparatus for driving an LED includes a power conversion module and a protection module. The power conversion module shifts the potential of an input voltage upward or downward according to a duty cycle of a PWM signal, and outputs a driving signal to drive the LED. In addition, the protection module determines a state of a protection signal to control the operation of the power conversion module according to the potential of the driving signal. When the potential of the driving is greater than a first preset value and smaller than a second preset value, the power conversion module is controlled to stop outputting the driving signal. When the potential of the driving signal is not greater than the first preset value and not smaller than the second preset value, the power conversion module is controlled operating normally.

Claims19

Dependent claims

A driving circuit of a light-emitting diode (LED), comprising:

a first inductor, having a first terminal coupled to an input voltage;
a first capacitor, having a first terminal coupled to a second terminal of the first inductor;
a switch, for determining whether or not to couple the second terminal of the first inductor to ground according to a PWM signal;
a second inductor, having a first terminal coupled to a second terminal of the first capacitor and a second terminal grounded;
a diode, having an anode terminal coupled to the second terminal of the first capacitor;
a second capacitor, having a first terminal coupled to a cathode terminal of the diode and a light source module to provide a driving signal to the light source module, and a second terminal grounded, wherein the light source module comprises at least an LED;
a load detector, for detecting a current of the light source module to output a feedback signal;
and
a signal generating unit, coupled to the load detector, for generating the PWM signal according to the feedback signal.

6 more elements

Dependencies are inferred from the claim text.

Light-emitting apparatus and driving circuit thereof

Life of this patent

Light-emitting apparatus and driving circuit thereof

Life of this patent

Abstract

Claims19