GB1343660A - Timepiece - Google Patents

Abstract

1343660 Electric watches SUWA SEIKOSHA K K 7 Dec 1971 [29 Dec 1970] 56766/71 Heading G3T In a battery powered electronic watch including a crystal controlled oscillator followed by a frequency divider and counters feeding timing data to a liquid crystal time display via a drive circuit Fig 4, while the oscillator, divider &c. which are composed of M.O.S.T. circuits, are energized continuously from the battery, a higher operating voltage for the liquid crystal is available on demand by closing a switch 7<SP>1</SP> Fig. 3 in a D.C./A.C./D.C. voltage step-up converter circuit. In the drive circuit Fig.4, each time a pulse is received at the base of a transistor 19 from the counter the output voltage of the converter circuit is applied to appropriate portions of the liquid crystal display 20, to indicate time. The converter circuit Fig.3 includes a pushpull transistor oscillator circuit (having a frequency of 500HZ-100KHZ) wherein a primary winding 11 on a toroidal ferrite core is connected to the collectors of transistors 8, 9 and the bases thereof are connected respectively to the ends of a detecting coil 12. The centre taps of winding 11 and coil 12 are joined via R13, C14. The resulting output voltage of a secondary winding 15 is full wave rectified and smoothed to provide say 20 volts from a battery voltage of 1.2.