US 2011/0298384 A1 · LED DRIVING DEVICE AND ELECTRICAL APPARATUS USING THE SAME

Abstract

A LED driving device 200 includes a LED driving IC 100, an inductor L1, a diode D1, a capacitor C1, and a backlight BL. The LED driving IC 100 includes an output control circuit 10 which generates a switching signal SD to convert an input voltage VIN to an output voltage VOUT supplied to a LED. The output control circuit 10 also generates a feedback voltage VR based on a terminal voltage inputted from the LED (i.e., a feedback input voltage). The LED driving IC 100 also includes a switching pulse adjustment circuit 30 to generate a third control signal SB and to provide the signal to the output control circuit 10. The third control signal SB is an adjusted signal of an ON time of the first control signal SA, based on the second control signal SC and the feedback voltage VR. The LED driving IC 100 also includes a signal judgment part 20 to generate a second control signal SC based on the first control signal SA.

Claims15

Dependent claims

A LED driving device comprising:

an output transistor to convert an inputted voltage to a predetermined output voltage and to supply the output voltage to a LED;
a signal judgment part to generate a second control signal based on a first control signal of a PWM signal;
a switching pulse adjustment circuit to generate a third control signal, which is an adjusted signal of an ON time of the first control signal, based on a feedback voltage according to a voltage drop of the LED, and based on the second control signal;
and
an output control circuit to generate a switching signal supplied to the output transistor based on the third control signal and the feedback voltage.

2 more elements

A LED driving device comprising:

an output transistor to convert an input voltage to a predetermined output voltage and to supply the output voltage to a LED;
a signal judgment part to generate a second control signal based on a first control signal of a PWM signal;
a switching pulse adjustment circuit to generate a third control signal, which is an adjusted signal of an ON time of the first control signal, based on a feedback voltage according to a voltage drop of the LED, and based on the second control signal;
an output control circuit to generate a switching signal supplied to the output transistor based on the third control signal and the feedback voltage;
and
a current driving circuit to supply a driving current to the LED based on the first control signal.

3 more elements

Dependencies are inferred from the claim text.

Led driving device and electrical apparatus using the same

Life of this patent

Led driving device and electrical apparatus using the same

Life of this patent

Abstract

Claims15