Patent ID: 7978171

Claim:
A control circuit of a driving circuit for controlling a light emitting diode (LED) light source having a plurality of areas, comprising: a plurality of error amplifiers, each of which receives a feedback current signal outputted from a specific area of the light source and an external reference voltage for generating an error signal; a buffer register receiving a serial digital signal, and generating a plurality of parallel digital signals; a work register receiving the plurality of parallel digital signals and a trigger signal, and outputting the plurality of parallel digital signals when the trigger signal is at a relatively high level; and a switch module having a plurality of power switches and coupled to the work register, each of the power switches receives a specific one of the error signals and a specific one of the parallel digital signals for generating a driving signal to control a driving current of a specific area of the light source, in order to control the brightness in each area of the LED light source, wherein the light source is a backlight module, and the driving circuit further comprises a control center generating the serial digital signal a driver generating the driving current, and an LED array module having a plurality of LED arrays, each of which comprises: an LED series having a plurality of LEDs, a first end coupled to the driver and a second end; an active power switch controlling a current of the LED series and comprising: a first end coupled to the second end of the LED series; a second end; and a control end receiving a specific one of the driving signals; a current detecting resistor detecting a standard value of a specific one of the driving currents passing through the LED series, comprising a first end coupled to the second end of the active power switch, and a second end coupled to a ground; an active switch protecting circuit comprising: a first voltage-divided resistor having a first end coupled to the first end of the current detecting resistor and a second end outputting a specific one of the feedback current signals; a silicon controlled rectifier (SCR) having an anode receiving a power voltage, a cathode coupled to the second end of the first voltage-divided resistor and a gate electrode; a zener diode having an anode coupled to the gate electrode of the silicon controlled rectifier and a cathode; a negative temperature coefficient (NTC) resistor having a first end coupled to the anode of the silicon controlled rectifier and a second end coupled to the cathode of the zener diode; and a second voltage-divided resistor having a first end coupled to the cathode of the zener diode and a second end coupled to the ground, wherein when a temperature of the active power switch is higher than a predetermined temperature, the active power switch will be turned off, and each of the driving currents drives a specific one of the areas of the light source for emitting a light.