| 摘要 |
PURPOSE:To eliminate malfunction of a logical circuit and liquid crystal display circuit by providing a constant voltage circuit and supplying selectively a constant voltage when the output voltage of a battery power sources drops considerably on account of heavy load driving of a lamp or the like. CONSTITUTION:When an outside switch SW of an electronic wristwatch or the like is turned on, a ligical circuit 12 outputs a lighting command signal l. Then a lamp 14 is lighted and a VHD circuit 16 acts as a voltage increasing to turn off the 1st voltage selecting circuit 15 and to turn on the 2nd voltage selecting circuit 18. The constant voltage (1.5V) outputted by a constant voltage circuit 17 is impressed as a voltage Vss1 to the circuit 12 and the 1st terminal of a liquid crystal display part 13 and the constant voltage (1.5V) is increased to 3V by the circuit 16 and is impressed as Vss2 to the 2nd terminal of the part 13. The output voltage Vc of a lithium battery 1 drops from ordinary 3V to about 2.5V, but the circuit 12 and the part 13 operate normally. |
