| 摘要 |
PROBLEM TO BE SOLVED: To reduce power consumption of an OP amplifier part and a liquid crystal display device. SOLUTION: A driving voltage circuit K1 is composed of a power source circuit 1a and a divided voltage generating circuit 2a and the power source circuit 1a is a multistage cascaded rectifier type boosting circuit, that is, the so-called cockroft circuit in which plural rectifiers are cascaded in multiple stages in parallel arms of a ladder-type circuit by alternately changing forward directions of the rectifiers and also capacitive elements are inserted in series arms of the ladder-type circuit. This power source circuit 1a is the boosting circuit boosting peak values VB of input pulses to (n) times (n is an integer of two or more). Moreover, the circuit 1a inputs a potential which is close to the divided voltage output V2 of an OP1 having the lowest voltage output and is lower than the voltage V2 to a negative power source terminal of two OP1, OP2 of a high voltage side and also it inputs a potential which is close to the divided voltage output V3 of an OP3 having the highest voltage output and is higher than the divided voltage output V3 to a positive power source terminal of two OP3, OP4 of a low voltage side.
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