LCD_WRISTWATCH

Published:2009/6/30 22:38:00 Author:May | From:SeekIC

Inverter section of Intel 5801 oscillator/divider is used with 32,768-Hz crystal to produce time base. First divider in 5801 reduces this to 1024 Hz for driving upcon-verter transistor. Feedback from transistor through 12-V zener is used to regulate and con-trol pulse width of 1024-Hz signal. Upconverter also provides 12-15 V required by LCD and 5201 decoder/driver IC. Output to each LCD segment and to common backplate is 32-Hz square wave.Separate drive flashes colon at 1-Hz rate.-M. S. Robbins, Electronic Clocks and Watches, Howard W, Sams, Indianapolis, IN, 1975, p 128-130.



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