LED backlight driving circuit, backlight module, and LCD device

摘要

The invention provides an LED backlight driving circuit, a backlight module, and an LCD device. The LED backlight driving circuit includes an LED light string; an input end of the LED light string is directly connected with an input end of a power source, and an output end of the LED light string is coupled with a buck module. In the invention, because the output end of the LED light string is in series connected with the buck module, the LED light string is connected in series between an input voltage and an output voltage, and a part of LEDs are directly supplied by the input voltage without the first stage conversion. Thus, the energy supplied by the buck module is reduced, the conversion efficiency is improved, the energy efficiency is increased, the requirement of the buck module to withstand voltage is reduced, and the device standard is decreased, thereby favoring cost reduction.

主权项

1. An LED backlight driving circuit, comprising: an input end of a power source electrically connected to one end of an energy storage inductor via two branches, wherein one branch comprises an LED light string and a diode, the other branch comprises a buck controllable switch, and the other end of the energy storage inductor is directly and always grounded, one end of said buck controllable switch is connected with said input end of said power source, and the other end of said buck controllable switch is connected with one end of the energy storage inductor; an anode of said diode is coupled with said output end of said LED light string; a cathode of said diode is electrically connected to one end of the energy storage inductor; an energy storage capacitor is connected in series between said cathode of said diode and a ground terminal of said input end of said power source; and the other end of the energy storage inductor is grounded.