LCD display and backlight apparatus and driving method thereof
View Patent ↗The backlight apparatus includes a light source module having a plurality of light sources connected in series, and a power supply module which generates a driving signal for driving the light source module according a synchronous control signal. A first switch is disposed between the light source module and power supply module, or between a last light source in the light source module and a reference voltage level. The first switch is turned on or off according to the synchronous control signal. In addition, a second switch determines whether or not to couple a function terminal of the power supply module to the reference voltage level to disable the driving signal without power off according to the synchronous control signal.
1. A backlight apparatus, comprising:
a light source module, having a plurality of light sources connected in series;
a power supply module for generating a driving signal according to a synchronous control signal, wherein the driving signal is configured to drive the light source module to emit light;
a first switch, disposed between a last light source in the light source module and a reference voltage level, wherein the first switch is configured to turn on or off according to the synchronous control signal; and
a second switch, for determining whether or not to couple a special function terminal of the power supply module to the reference voltage level in order to disable the driving signal without power off the power supply module according to the synchronous control signal.
2. The backlight apparatus according to claim 1 , wherein the first switch is a NMOS transistor having a gate coupled to the reference voltage level via the second switch, and a first source/drain and a second source/drain coupled to the last light source and ground, respectively.
3. The backlight apparatus according to claim 1 , wherein the reference voltage level is ground voltage level.
4. The backlight apparatus according to claim 1 , wherein the light sources are LEDs, and the cathode of each of the LEDs is coupled to the anode of a next LED.
5. The backlight apparatus according to claim 1 , wherein the light sources are connected in series.
6. A backlight apparatus, comprising:
a light source module, having a plurality of light sources connected in series;
a power supply module, for generating a driving signal according to a synchronous control signal for driving the light source module;
a first switch, disposed between a first light source of the light source module and the power supply module, wherein the first switch is configured to pass the driving signal to the light source module according to the synchronous control signal; and
a second switch, for determining, according to the synchronous control signal, whether or not to couple a function terminal of the power supply module to a reference voltage level in order to disable the driving signal.
7. The backlight apparatus according to claim 6 ,
further comprising a third switch for controlling the first switch according to the synchronous control signal;
wherein the first switch is a NMOS transistor having a first source/drain for receiving the driving signal, a second source/drain coupled to the light source module, and a gate controlled by the third switch.
8. The backlight apparatus according to claim 7 , wherein the third switch is a NMOS transistor, that includes a grounded first source/drain, a gate for receiving the synchronous control signal, and a second source/drain connected to the gate of the first switch via a resistor.
9. The backlight apparatus according to claim 6 , wherein the reference voltage level is ground voltage level.
10. The backlight apparatus according to claim 6 , wherein the light sources are light emitting diodes (LEDs), and each cathode of the LEDs is coupled to the anode of a next LED.
11. A driving method of a backlight apparatus, wherein the backlight apparatus has a plurality of light sources and a power supply module, and the driving method comprises:
generating a synchronous control signal;
providing a reference voltage level:
generating a driving signal, wherein the light sources are driven according to the voltage difference between the voltage level of the driving signal and the reference voltage level;
determining whether or not to conduct the driving signal to the light sources according to the synchronous control signal; and
determining, according to the synchronous control signal, whether or not to disable the driving signal without powering off the power supply module.
12. The driving method according to claim 11 , wherein the reference voltage level is ground voltage level.
13. The driving method according to claim 11 configured for controlling the backlight of a liquid crystal display (LCD).