| 摘要 |
The present invention discloses an LED backlight system and a display device. The LED backlight system includes an LED display module and an LED backlight control circuit. The LED display module includes LED string. The LED backlight control circuit includes a current module, a comparison unit, a control switch unit, and an impedance unit wherein, an input terminal of the comparison unit obtains a voltage at a negative terminal of the LED string, and when the voltage at the negative terminal is greater than a preset threshold voltage, the comparison unit controls the control switch unit to turn on such that the impedance unit connects in parallel with the current module so as to decrease the voltage at the negative terminal. Through above way, the present invention can prevent the unstability of the circuit loop in order to prevent the flicker phenomenon of the backlight system. |
| 主权项 |
1. An LED backlight system comprising:
a power module for providing a power source; an LED display module connected to the power module and including a plurality of LED strings connected in parallel; and an LED backlight control circuit including:
a plurality of current modules having the same number as the LED strings and electrically connecting to the corresponding LED strings to provide working currents for the LED strings; anda plurality of control modules having the same number as the LED strings and each of the control modules includes a comparison unit, a control switch unit connected to the comparison unit, and an impedance unit connected to control switch unit, wherein, an input terminal of the comparison unit obtains a voltage at a negative terminal of the LED string, and when the voltage at the negative terminal is greater than a preset threshold voltage, the comparison unit outputs a control signal to control the control switch unit to turn on such that the impedance unit connects in parallel with the current module so as to increase the working current of the LED string in order to decrease the voltage at the negative terminal; wherein, the power module includes an inductor and a diode, wherein a positive, terminal of the diode connects to the inductor, and a negative terminal of the diode connects to positive terminals of the LED strings; and the comparison unit is a comparator, the control switch unit is a first switch, and the impedance unit is an adjustable resistor, wherein a first input terminal of the comparator connects to the negative terminal of the LED string; a second input terminal of the comparator receives the preset threshold voltage; an output terminal of the comparator outputs the control signal, and a gate electrode of the first switch connects to the output of the comparator; a source electrode of the first switch connects to one end of the current module, and the other end of the current module connects to one end of the adjustable resistor, and the other end of the adjustable resistor connects to a drain electrode of the first switch. |
