UPD16681A Просмотр технического описания (PDF) - NEC => Renesas Technology

Номер в каталоге

Компоненты Описание

Список матч

UPD16681A

LCD CONTROLLER/DRIVER FOR DOT MATRIX DISPLAY OF JIS LEVEL 1 AND JIS LEVEL 2 KANJI SETS

NEC => Renesas Technology 

µPD16681A

4. POWER SUPPLY CIRCUIT

A switchable (3x or 4x) boost circuit is included to generate a current for driving the LCD. A connection to a boost-

related capacitor is used to switch the boost circuit’s setting.

The VEXT pin (H: external, L: internal) is used to switch between using an external LCD driver power supply or the

on-chip boost circuit.

4.1 Boost Circuit

When using the internal power supply, connect the boost-related capacitor between C1+ and C1−, C2+ and C2−, and

C3+ and C3−. Also, connect the capacitor for level stabilization between VLCD and VSS, and set VEXT low to boost the

potential between VDD and VSS from 3 to 4 times.

Since the boost circuit uses signals from the internal oscillation circuit, the oscillation circuit must be operating. The

relation between the boosted voltage and the potential is described below.

The C1+ to C3− and VDD pins all relate to the boost circuit, so the wire impedance should be minimized.

Figure 4−1. 3x and 4x Boost Mode

VLCD = 4VDD = 12 V

(During 4x boost mode)

VLCD = 3VDD = 9 V

(During 3x boost mode Note )

VDD = 3 V

VSS = 0 V

Note When set for 3x boost, connect boost-related capacitors between C2− and C3+ and C1+ and C1−.

8

Data Sheet S14207EJ3V0DS

Share Link: