UPD16635 datasheet(6/19 Pages) NEC

6 / 19 page

µPD16635

RELATIONSHIP BETWEEN INPUT DATA AND OUTPUT VOLTAGE VALUE

This product incorporates a 6-bit D/A converter whose odd output pins and even output pins output

respectively gray scale voltages of differing polarity with respect to the LCD’s counter electrode (common

electrode) voltage. The D/A converter consists of ladder resistors and switches. The ladder resistors r0 to r62

are so designed that the ratios between the LCD panel’s

γ -corrected voltages and V0’ to V63’ and V0” to V63” are

roughly equal; and their respective resistance values are as shown on page 9. Among the 5-by-2

γ -corrected

voltages, input gray scale voltages of the same polarity with respect to the common voltage, for the respective

five

γ -corrected voltages of V0 to V4 and V5 to V9. If fine gray scale voltage precision is not necessary, the voltage

follower circuit supplied to the

γ -corrected power supplies V1 to V3 and V6 to V8 can be deleted.

Figure 1 shows the relationship between the driving voltages such as liquid-crystal driving voltages VDD2 and

VSS2, common electrode potential VCOM, and

γ -corrected voltages V0 to V9 and the input data. Be sure to maintain

the voltage relationships of VDD2 > V0 > V1 > V2 > V3 > V4 > V5 > V6 > V7 > V8 > V9 > VSS2. Figures 2-1 and 2-

2 show the relationship between the input data and the output data. Table 1 shows the resistance values of

the resistor strings.

This driver IC is designed for single-sided dot inversion mounting. Therefore, it cannot be used in double-

sided mounting.

Figure 1. Relationship Between Input Data and Output Voltage

VDD2

0.2 V

VCOM

0.2 V

VSS2

Input data (HEX)

Split interval

UPD16635 Datasheet(PDF) 6 Page - NEC