MIC2950/2951
Micrel
+V
IN
8
+5V
4.7mA
20mA
4
8
470kΩ
OUTPUT*
+V
IN
1
V
5
IN
V
1
7
OUT
5
V
ERROR
OUT
1
7
V
470kΩ
OUT
FB
1N
4001
R
R
1
MIC2951
MIC2951
4
+
3
FB
1µF
0.1µF
SD
2
RESET
* HIGH FOR
< 3.5mA
2
GND
4
GND
4
I
L
360
1N457
MIN. VOLTAGE 4V
Latch Off When Error Flag Occurs
Open Circuit Detector for 4mA to 20mA Current Loop
8
2
+V
SENSE
39kΩ
IN
+V
+
= 5V
1
7
OUT
3
5
V
OUT
ERROR
MIC2951
RESET
1µF
–
3
FB
SD
C4
+
GND
4
TAP
6
39kΩ
+
100
6V
100kΩ
1%
1%
1%
–
kΩ
LEAD-
ACID
C1
+
<5.8V**
<6.0V**
<6.2V**
BATTERY
1
kΩ
100kΩ
100kΩ
–
C2
+
C1-C4
LP339
1
kΩ
–
C3
+
10kΩ
R
3
870 33
1% 20kΩ
C1 TO C4 ARE COMPARATORS (LP339 OR EQUIVALENT)
*OPTIONAL LATCH OFF WHEN DROP OUT OCCURS. ADJUST R3 FOR C2
SWITCHING WHEN V IS 6.0V
IN
**OUTPUTS GO LOW WHEN V DROPS BELOW DESIGNATED THRESHOLDS.
IN
Regulator with State-of-Charge Indicator
February 1999
3-61
MICREL [ MICREL SEMICONDUCTOR ]
