Specifications

LQ-2080 Revision A
Operating Principles Control Circuit 25
2.3.1 System Reset Circuit
Control circuits IC3 and IC4 are initialized when a /RESET signal (LOW
level) is output from port 1 (VOUT) of IC2. IC2 monitors the +5 V line on
port 3, and resets under the following conditions:
1. When the power supply is turned on, a /RESET signal is output.
/RESET is canceled when the +5 V line goes up to 4.2 V, and then
100 ms passes.
2. When the +5 V line goes below +4.2 V, a /RESET signal is output.
/RESET is canceled when the +5 V line goes back up to 4.2 V and
then 100 ms passes.
Figure 2-3. Reset Circuit
Figure 2-4. Reset Signal Output Timing
VOUT
MRES
VCC
GND
+5V
+5V
R63
1K
IC 2
PS T5920
C36
0.1U
IC 4
IC 3
E05B 24Y A
TP M 96C 041A
F
23 R ES E T
74
RESET
1
2
3
4
1
2
3
4
5
VCC (+5V line)
VOUT (RESET)
RESET
RESET
Power On
(v )
100m s
100m s