| 摘要 |
PROBLEM TO BE SOLVED: To obtain a gate voltage that depends on the load state by monitoring undervoltage of a pumping capacitor in a charge-pump step-up section. SOLUTION: A gate select voltage Vgh and a gate non-select voltage Vgl from a gate select voltage generating section 103 and a gate non-select voltage generating section 104 are outputted to a section 12 for driving the scanning line of a liquid crystal display section 13. The low voltage of the pumping capacitor in charge pump step-up sections 16 and 17 is sampled at sampling sections 18 and 19 and is then monitored at output monitoring sections 6 and 9. Depending on the monitor output, a step-up power supply generating section 8 controls a step-up power supply voltage Vin_h, and a step-up clock generating section 10 controls step-up clock ck_l, before being delivered, respectively, to charge pump step-up sections 16 and 17. COPYRIGHT: (C)2007,JPO&INPIT
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