S6A0093 Datasheet, PDF (38/54 Pages) Samsung semiconductor – 80 SEG / 26 COM DRIVER & CONTROLLER FOR STN LCD

80 SEG / 26 COM DRIVER & CONTROLLER FOR STN LCD
S6A0093
VOLTAGE REGULATOR
The Voltage Regulator circuit is used to obtain an appropriate LCD panel driving voltage. This voltage is obtained by
adjusting resistors Ra and Rb as shown in equation (1) or (2), and by setting electronic contrast control data bits, see
equation (3) or (4).
The potential of V0 Pin can be adjusted within VOUT - VREF. VREF is the internal constant voltage source of the chip
and this value is 2.0V in the condition VDD ≥ 2.4V
The REF selects which voltage is used for voltage regulator between the external VEXT and the internal VREF.
n Voltage regulation by adjusting resistors Ra, Rb
When REF is "Low"
When REF is "High"
V0 = ( 1 +
Rb
) x VREF --- (1)
Ra
Rb
V0 = ( 1 +
) x VEXT --- (2)
Ra
The internal VREF of voltage regulator has the temperature compensation function, and the temperature coefficient
is about 0.0%/°C.
Rb
VOUT
VR
_
+
Ra
VEXT
VREF
Inside Chip
VSS
GND
Figure 19. Voltage Regulator Circuit
V0
REF
35