CHAPTER 3 INSTALLATION
User’s Manual U16290EJ1V0UM
35
(2) External boost circuit
SW1 of the external boost circuit is set to OFF at shipment, and connection of an external boost circuit is
possible by setting this switch to ON. The external boost circuit is a circuit that re-boosts the reference value set
to VLCD00 (FFB3H). VR1 is used to adjust the V
LC3
voltage (1.6 V to 2.2 V) and boost the voltage level of the
LCD reference voltage (V
LC0
to V
LC4
). The V
LC0
voltage can be adjusted up to the standard value
−
0.35 V
±
15%.
At shipment, VR1 is set to VLC3 = 2.0 V. The V
LC3
voltage can be measured with the check pin (CP57).
Figure 3-19. Variable Resistance of External Boost Circuit
VR1
HIGH
VLC
LOW
SW1
OFF
ON
CP57
VLC3
LOW
HIGH
VR1
CP57
VLC3
1.6 V to 2.2 V
Table 3-7. Switch Settings of External Boost Circuit
ON: Connect
circuit
SW1
OFF: Disconnect circuit (initial setting)
