A_D_converter_for_a_41_2_digit_LCD_display

Published:2009/7/24 10:19:00 Author:Jessie | From:SeekIC

This circuit shows an ICL8052/ICL71C03 chip pair with an ICM7211 driver, which can be used to operate a 41/2-digit LCD display. With the values shown, the full-scale is ±2.000 V. Data bits are latched into the driver by the STROBE signal and Overrange is indicated by blinking the 4 digits. A 120-kHz clock is provided by an ICM7555. Figure 6-22B shows a gross overvoltage protection circuit (to be added if required). If the capacitor is added to put 36 of the ICM7211, the LCD backplane oscillator frequency is reduced from about 150 Hz. To adjust, short terminals 10 and 11 of the ICL71C03 and check that the display is 0000. Then, apply 2.000 V at terminals 10 and 11, and adjust the 10-kΩ potentiometer (pin 7 of the ICL71C03) for a reading of 2000 on the display. Harris Semiconductors, Data Acquisition, 1991, p. 2-25, 2-26.



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