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17
SVD (Supply Voltage Detection) Circuit
[S1C63004/008/016]
Note: The S1C63003 has no SVD circuit included.
17.1
Configuration of SVD Circuit
The S1C63004/008/016 has a built-in SVD (supply voltage detection) circuit, so that the software can find when the
source voltage lowers. Turning the SVD circuit on/off and the SVD criteria voltage setting can be done with software.
Figure 17.1.1 shows the configuration of the SVD circuit.
17.2
SVD Operation
The SVD circuit compares the criteria voltage set by software and the supply voltage (V
and sets its results into the SVDDT latch. By reading the data of this SVDDT latch, it can be determined by means
of software whether the supply voltage is normal or has dropped.
The criteria voltage can be selected from 29 types shown in Table 17.2.1 using the SVDS[4:0] register.
SVDS[4:0]
1FH
1EH
1DH
1CH
1BH
1AH
19H
18H
17H
16H
15H
14H
13H
12H
11H
10H
When the SVDON register is set to "1," supply voltage detection by the SVD circuit is executed. As soon as the SV-
DON register is reset to "0," the result is loaded to the SVDDT latch and the SVD circuit goes off.
To obtain a stable detection result, the SVD circuit must be on for at least 500 µsec. So, to obtain the SVD detection
result, follow the programming sequence below.
1. Set SVDON to "1"
2. Maintain for 500 µsec minimum
3. Set SVDON to "0"
4. Read SVDDT
When the SVD circuit is on, the IC draws a large current, so keep the SVD circuit off unless it is necessary.
S1C63003/004/008/016 TeChniCal Manual
(Rev. 1.1)
V
DD
Detection output
SVD circuit
V
SS
Criteria voltage
setting circuit
Figure 17.
1.1 Configuration of SVD circuit
Table 17.
2.1 Criteria voltage
Criteria voltage (V)
3.20
3.10
3.00
2.90
2.80
2.70
2.60
2.50
2.40
2.30
2.20
2.10
2.00
1.90
1.80
1.70
Seiko epson Corporation
17 SVD (SuPPlY VOlTaGe DeTeCTiOn) CiRCuiT
SVDDT
SVDON
SVDS4
|
SVDS0
DD
SVDS[4:0]
Criteria voltage (V)
0FH
0EH
0DH
0CH
0BH
0AH
09H
08H
07H
06H
05H
04H
03H
02H
01H
00H
terminal–V
terminal)
SS
1.65
1.60
1.55
1.50
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
17-1
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