US 8,941,326 B2 · AC-DC dual-use LED driving circuit

Abstract

An Alternating-current-Direct-current (AC-DC dual-use) Light Emitting Diode (LED) driving circuit includes an input power circuit, a buck-boost converter, and a Pulse Width Modulation (PWM) signal controller. The buck-boost converter, including a switching transistor and a feedback resistor, receives a current signal output from the input power circuit, and drives an LED with a driving signal. The PWM signal controller outputs a PWM signal according to the driving signal, so as to sequentially turn on and turn off the switching transistor. One end of the feedback resistor is coupled to the LED, and a floating ground terminal of the PWM signal controller is coupled to the switching transistor and the other end of the feedback resistor. Therefore, the AC-DC dual-use LED driving circuit is capable of dynamically adjusting the duty ratio of the PWM signal without connecting an external photocoupler.

Claims16

Dependent claims

An Alternating-current-Direct-current (AC-DC) dual-use Light Emitting Diode (LED) driving circuit, suitable for driving an LED, comprising:

an input power circuit for outputting a current signal;
a buck-boost converter for receiving the current signal and outputting a driving signal, the AC-DC dual-use LED driving circuit driving the LED by the driving signal, the buck-boost converter comprising a switching transistor and a feedback resistor, and one end of the feedback resistor coupled to the LED;
and
a Pulse Width Modulation (PWM) signal controller for outputting a PWM signal according to the driving signal for sequentially turning on and turning off the switching transistor, a floating ground terminal of the PWM signal controller coupled to the switching transistor and the other end of the feedback resistor.

1 more element

Dependencies are inferred from the claim text.

AC-DC dual-use LED driving circuit

Life of this patent

AC-DC dual-use LED driving circuit

Life of this patent

Abstract

Claims16