Abstract: A variable gain device having higher linearity and wider gain range is provided. The variable gain device includes a transduction unit for generating an output current, a control unit for adjusting the current gain of the gain amplifying unit according to a gain control signal, a gain amplifying unit receiving the current signal and generating a gain adjustable current according to the current gain of the control unit, an output DC level control unit controlling the DC level of the output signal of the variable gain device, and an output unit generating an output signal according to the signals output by the output DC level control unit and the gain amplifying unit.

Abstract: A digital to analog converter for an analog Liquid Crystal Display (LCD) includes a digital inlet, a latching circuitry, a voltage level shifter circuitry, a switching circuitry, and a resistance network with a resistance compensatory circuitry. The resistance network with the resistance compensatory circuitry is electrically connecting with the switching circuitry and adapted to regulate a pattern of the analog output signal so as to optimize the analog output signal. Specifically, the resistance network with a resistance compensatory circuitry is to produce the best linear conversion from the digital signal to the analog signal for use by the LCD.