LED BACKLIGHT DRIVING CIRCUIT, BACKLIGHT MODULE, AND LIQUID CRYSTAL DISPLAY DEVICE

摘要

Disclosed are an LED backlight driving circuit, a backlight module, and a liquid crystal display device. The LED backlight driving circuit comprises an LED light bar and a control module. The control module comprises a dimming controllable switch (Q1), the LED light bar is connected in series to the dimming controllable switch (Q1), and piezoresistors (R1) are set in parallel at two ends of the dimming controllable switch (Q1). When the dimming controllable switch (Q1) is turned off, because a branch current is reduced suddenly, a voltage on the LED light bar is decreased; therefore, a voltage at the two ends of the dimming controllable switch (Q1) is increased. In this case, resistance of the piezoresistors (R1) connected in parallel to the dimming controllable switch (Q1) is decreased under the high voltage, so that the voltage at two ends of the LED light bar is increased and at the same time, the voltage at the two ends of the dimming controllable switch (Q1) is decreased. Therefore, the problem that a withstand voltage is excessively high when the dimming controllable switch (Q1) is turned off is solved.