SIGNAL LEVEL CONVERSION CIRCUIT AND ACTIVE MATRIX LIQUID CRYSTAL DISPLAY DEVICE PROVIDED WITH THE SIGNAL LEVEL CONVERSION CIRCUIT

摘要

PROBLEM TO BE SOLVED: To obtain a signal level conversion circuit that normally converts the level of an input signal into a high level and provides the output a TFT integrated circuit whose power supply voltage is higher than a 1st circuit even when a threshold of an input transistor(TR) is changed due to change over aging or the like and the low level signal input from a MOSFET integrated circuit becomes smaller than the threshold. SOLUTION: The signal level conversion circuit 13 that receives a low level signal, converts it into a high level signal and provides the output of it, is provided with a level conversion section that includes input TRs Q1, Q2 and converts the low level signal into the high level signal and with threshold detection circuits 20, 21 that detect a threshold of the input TRs Q1, Q2 every prescribed period. The threshold detected by the threshold detection circuit 20 is added to the low level signal and gives the resulting signal to the gate of the input TR Q1 and the threshold detected by the threshold value detection circuit 21 is added to the bias voltage VB and gives the resulting signal to the gate of the input TR Q2.