| 摘要 |
PURPOSE:To eliminate an influence of the drop of an electric power voltage by making a double flip-flop connection between two stages of inverters and by comparing a battery voltage with a boosted voltage for driving liquid crystals. CONSTITUTION:When input voltage Vin is less than VDD and greater than VSS, the 2nd transistor 11 and 4th transistor 15 are on and off respectively and Va and Vb are -VSS and VDD respectively. When VSS=Vin, transistors 11 and 15 are both off and Va and Vb are held at the potentials by the electrostatic capacity. When VDD>VSS>Vin, transistor 11 and 15 are off and on respectively and Va and Vb are VDD and -Vss respectively. Therefore, there is the operating point nearly at electric power voltage VSS and input voltage Vin can be detected accurately. |
