hd66717 Renesas Electronics Corporation., hd66717 Datasheet - Page 51

• Manufacturer Part Number: hd66717
• Description: Low-power Dot-matrix Liquid Crystal Display Controller/driver -
• Manufacturer: Renesas Electronics Corporation.

HD66717
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 30. Here, contrast can be adjusted through the CT bits of
the contrast-control instruction.
The HD66717 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
and V1 and between V
and V5 must be 0.4V or
CC
EE
greater. Note that the OPOFF pin must be grounded when using the operational amplifiers.
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