
S1C6S3N7 TECHNICAL HARDWARE
EPSON
I-61
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (SVD Circuit and Heavy Load Protection Function)
The S1C6S3N7 Series have a heavy load protection function
for when the battery load becomes heavy and the supply
voltage drops, such as when a melody is played or an exter-
nal lamp lights. This functions works in the heavy load
protection mode.
(1) In cace of S1C6S3L7/S1C6S3B7
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
When the SVD circuit detects a supply voltage less
than l.2 V, in which case the mode is automatically
changed to the heavy load protection mode
(2) In case of S1C6S3N7
The normal mode changes to the heavy load protection
mode in the following case:
When the software changes the mode to the heavy load
protection mode (HLMOD = 1)
Based on the operation of the SVD circuit and the heavy
load protection function, the S1C6S3L7/S1C6S3B7 obtains
an operation supply voltage as low as 0.9 V. See the
electrical characteristics for the precision of voltage detec-
tion by the SVD circuit.
In the heavy load protection mode, the internally regulated
voltage is generated by the liquid crystal driver supply
output, VL2, in order to operate the internal circuit
(S1C6S3L7/S1C6S3B7). Consequently, more current is
consumed in the heavy load protection mode than in the
normal mode. Unless necessary, do not select the heavy
load protection mode with the software.
Operation of heavy
load protection
function
Activation of the SVD circuit by software in the heavy load protec-
tion mode causes a malfunction. Avoid such activation if possible.
Note