
II-44
EPSON
S1C6S3N7 TECHNICAL SOFTWARE
CHAPTER 3: PERIPHERAL CIRCUITS (SVD Circuit and Heavy Load Protection Function)
Heavy load protec-
tion function
Note that the heavy load protection function on the
S1C6S3L7/S1C6S3B7 are different from the S1C6S3N7.
(1) In case of S1C6S3L7/S1C6S3B7
The S1C6S3L7/S1C6S3B7 have the heavy load protec-
tion function for when the battery load becomes heavy
and the source voltage drops, such as when an external
buzzer sounds or an external lamp lights. The state
where the heavy load protection function is in effect is
called the heavy load protection mode. In this mode,
operation with a lower voltage than normal is possible.
The normal mode changes to the heavy load protection
mode in the following two cases:
When the software changes the mode to the heavy load
protection mode (HLMOD = "1")
When supply voltage drop (SVDDT = "1") in the SVD
circuit is detected, the mode will automatically shift to
the heavy load protection mode until the supply volt-
age is recovered (SVTDT = "0")
In the heavy load protection mode, the internally regu-
lated voltage is generated by the liquid crystal driver
source output VL2 so as to operate the internal circuit.
Consequently, more current is consumed in the heavy
load protection mode than in the normal mode. Unless it
is necessary, be careful not to set the heavy load protec-
tion mode with the software. Also, to reduce current
consumption, do not set the SVDON to ON in the heavy
load protection mode.
(2) In case of S1C6S3N7
The S1C6S3N7 has the heavy load protection function for
when the battery load becomes heavy and the source
voltage changes, such as when an external buzzer sounds
or an external lamp lights. The state where the heavy load
protection function is in effect is called the heavy load
protection mode. Compared with the normal operation
mode, this mode can reduce the output voltage variation
of the constant voltage or voltage booster/reducer of the
LCD system.