LED scanning array driver chip and regulation method capable of self-regulating brightness linear change

1. An LED (light emitting diode) scanning array driver chip capable of self-regulating brightness linear change, comprising:

a I2C (inter-integrated circuit) series communication interface, consisting of a SCL (serial clock line) and a SDL (serial data line), the I2C serial communication interface being connected with a control register and able to read/write the control register;

the control register, comprising (1) on/off control registers, each LED being provided with an on/off control register for controlling a corresponding one of LEDs to light or extinguish; (2) PWM (pulse width modulation) registers, each LED being provided with a PWM register for controlling a duty cycle of LED current; (3) current non-linear automatic regulation selection registers, each LED being provided with a current non-linear automatic regulation selection register for controlling the corresponding LED to select one of current non-linear automatic regulations; (4) software interrupt registers, the I2C serial communication interface being able to read the software interrupt registers to check which one of current non-linear automatic controls is over; (5) a synchronous clock control register, controlling three state of a pin, the three states being (a) a high-impedance state; (b) an output state, outputting a square wave signal at a certain frequency, other chips inputting the square wave signal, enabling the LED current non-linear automatic controls of other chips to be synchronized with the chip; (c) an input state, inputting a square wave signal as a clock signal for the chip to drive the LED current non-linear automatic controls;

a synchronous clock control circuit, connected with the control register, for controlling the input state, the output state, and the high-impedance state of the pin of the synchronous clock control register;

LED current non-linear automatic control circuits, connected with the synchronous clock control circuit and the control register, with a current ratio of the current nonlinear automatic regulations of multiple step LEDs, when the PWM register regulates the duty cycle of the LED current, the LED current non-linear automatic control circuits regulate the DC current of the LEDs to achieve a self-regulation of average current of the LEDs, without affecting the function of the PWM to regulate the average current;

an LED scanning timing control circuit, a current source circuit, and an open-drain output circuit, the current source circuit and the LED scanning timing control circuit being connected with the LED current non-linear automatic control circuits, the open-drain output circuit being connected with the LED scanning timing control circuit.

2. The LED scanning array driver chip capable of self-regulating brightness linear change as claimed in claim 1 , wherein the open-drain output circuit has an output pin which is an open-drain output, the chip is externally connected with a pull-up resistor, when the control of any one of the LED current non-linear automatic control circuits is over, the input pin is pulled down to the bottommost to output low-level current.

3. The LED scanning array driver chip capable of self-regulating brightness linear change as claimed in claim 1 , wherein the control register further comprises a state checking register, and a MCU (microprogrammed control unit) reads the state checking register to check the current state of any one of the LED current non-linear automatic controls.

4. A brightness linear change self-regulation method of an LED (light emitting diode) scanning array driver chip, comprising the steps of: a MCU (microprogrammed control unit) reading/writing a control register through a I2C serial communication interface, the control register comprising an on/off control register, a PWM register, a current non-linear automatic regulation selection register, a software interrupt register, and a synchronous clock control register for each LED, the on/off control register controlling a corresponding one of LEDs to light or extinguish, the PWM register controlling a duty cycle of the corresponding LED, the current non-linear automatic regulation selection register being controlled by LED current non-linear automatic control circuits for controlling the corresponding LED to select which one of the current non-linear automatic for controls, while the PWM register regulates the duty cycle of the LED current, the LED current non-linear automatic control circuits cooperating with the current non-linear automatic regulation selection register to regulate the DC current of the LEDs to achieve a self-regulation of average current of the LEDs, without affecting the function of the PWM to regulate the average current; the I2C serial communication interface reading the software interrupt register to check which one of the current non-linear automatic controls is over, the synchronous clock control register being controlled by a synchronous clock control circuit, the chip having an input state, an output state and a high-impedance state, wherein when in the output state, a pin of the synchronous clock control register outputs a square wave signal and other chips input the square wave signal, enabling the LED current non-linear automatic controls of the other chips to be synchronized with the chip; when in the output state, the pin of the synchronous clock control register inputs a square wave signal as a clock signal for the chip to drive the LED current non-linear automatic controls.