HD66727 Datasheet, PDF (59/97 Pages) Hitachi Semiconductor – Low-Power Dot-Matrix Liquid Crystal Display Controller/Driver with Key Scan Function

HD66727
Power Supply for Liquid Crystal Display Drive
When External Power Supply and Internal Operational Amplifiers are Used
To supply LCD drive voltage directly from the external power supply without using the internal booster,
circuits should be connected as shown in Figure 33. Here, contrast can be adjusted through the CT bits of
the contrast control instruction.
The HD66727 incorporates a voltage-follower operational amplifier for each of V1 to V5 to reduce current
flowing through the internal bleeder-resistors, which generate different levels of liquid-crystal drive
voltages. Thus, potential differences between V_CC and V1 and between V_EE and V5 must be 0.4V or greater.
Note that the OPOFF pin must be grounded when using the operational amplifiers.
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