UPD16488AP datasheet(34/91 Pages) NEC

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Data Sheet S15745EJ2V0DS

µµµµPD16488A

(2) When using an external resistor (instead of using the on-chip resistor for VLCD voltage regulation)

Instead of using only the on-chip resistor setting for VLCD voltage regulation (IRS = L), resistors (Ra', Rb' and Rc') can be

added between VSS and VR, between AMPOUTP and AMPOUT, and between VR and AMPOUT to set the LCD drive voltage

VLCD. In such cases, the electronic volume function can be used to control the LCD drive voltage VLCD and to regulate the

contrast of the LCD contents via commands.

In addition, the

µPD16488A enable selection between two display values (for normal display and partial display). The

value is set using an external division resistor and is automatically selected by the DTY flag in the control register 2 (R1).

The VLCD value can be determined using Example 1 (DTY = 0) and Example 2 (DTY = 1) if it is within the range of VLCD

VOUT.

Example 1. DTY = 0, normal display mode

VLCD = (1 +

′

′ ) VEV

VLCD = (1 +

′

′ ) (1 −

384

α ) VREG

Remark VEV (1

−

384

α ) VREG

Example 2. DTY = 1, partial display mode

VLCD = (1+

Rc)

′

) VEV

VLCD = (1+

()

′

) (1

−

384

α ) VREG

Remark VEV = (1

−

384

α ) VREG

Figure 5-13. When Using External Resistor

Rb'

Ra'

VLCD

AMPOUT

AMPOUTP

Normal/partial VLC1 regulation

select circuit

Normal display mode

Partial display mode

(DTY = 0)

(DTY = 1)

UPD16488AP Datasheet(PDF) 34 Page - NEC

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