SNAD02C
8-CHANNEL 10-BIT ADC
6.9. Battery Monitoring (Channel 7 only)
VDD
ENCH[7]
DI[7]
PH&ENCH[x]
30k
20k
10k
CH[7]
to ADC
PL&ENCH[x]
Battery
ENCH[7]
VSS
VSS
VSS
Figure-12 The circuit of the Input pad of Channel 7
(1) While read ADC command is sent and channel 7 is selected, ADC can be used to monitor the
battery voltage.
(2) The circuit of battery voltage monitoring is shown in Figure-12 (Channel7 only)
(3) The battery voltage is six times ADC measuring voltage. Thus, the measured result equals to
1/6*battery voltage.
(4) While channel 7 is set to the analog input mode, an input resistor (60kΩ) exists from CH[7] to
VSS. To save unnecessary power consumption, CH[7] should be switch to digital input type
when CH[7] is not measured.
Note:
CH[7] is different from the other 7 channels. The input voltage is reduced to 1/6 before it is sent into
ADC.
Version: 1.3
July 31, 2003
13
SONIX [ SONIX TECHNOLOGY COMPANY ]
