Table of Contents
Advertisement
4.4 Heavy Load Protection Function
In order to ensure a stable circuit behavior and LCD display quality even if the power supply voltage fluctuates due
to driving an external load, the internal logic voltage regulator and the LCD system voltage regulator have a heavy
load protection function.
The internal logic voltage regulator enters heavy load protection mode by writing 1 to the HVLD bit (D4/VD1_CTL
register) and it ensures stable V
or buzzer is driven with a port output.
∗ HVLD: V
Heavy Load Protection Mode Bit in the V
D1
The LCD system voltage regulator enters heavy load protection mode by writing 1 to the LHVLD bit (D4/
LCD_VREG register) and it ensures stable V
display has inconsistencies in density.
∗ LHVLD: LCD Heavy Load Protection Mode Bit in the LCD Voltage Regulator Control (LCD_VREG) Register
(D4/0x50a3)
Note: Current consumption increases in heavy load protection mode, therefore do not set heavy load
protection mode with software if unnecessary.
S1C17704 TECHNICAL MANUAL
output. Use the heavy load protection function when a heavy load such as a lamp
D1
D1
–V
outputs. Use the heavy load protection function when the LCD
C1
C5
EPSON
Control (VD1_CTL) Register (D4/0x5120)
4 POWER SUPPLY
4-5
Advertisement
Table of Contents
