Datasheet

V
(BATT)
R1
R
CL
0.1%
TL1431
I
O
+
V
I(ref)
R
CL
) I
KA
I
O
R1 +
V
(BATT)
ǒ
I
O
h
FE
Ǔ) I
KA
V
(BATT)
TL1431
I
O
R
S
0.1%
I
O
+
V
I(ref)
R
S
TL1431
12 V
680 Ω
2 kΩ
R
Off
On
C
Delay + R C I
I
12 V
(
12 V
)
* V
I(ref)
V
(BATT)
R3
R4
R1A
R2A
R1B
R2B
TL1431
Low Limit +
ǒ
1 )
R1B
R2B
Ǔ
V
I(ref)
High Limit +
ǒ
1 )
R1A
R2A
Ǔ
V
I(ref)
LED on When
Low Limit < V
(BATT)
< High Limit
TL1431
+
−
TL1431
12 V
6.8 kΩ
5 V +0.5%
10 kΩ
10 kΩ
0.1%
10 kΩ
0.1%
V
CC
X
Not
Used
TL598
Feedback
TL1431
SLVS062M –DECEMBER 1991–REVISED APRIL 2012 www.ti.com
Figure 24. PWM Converter With 0.5% Reference
A. Select R3 and R4 to provide the desired LED intensity and cathode current ≥1 mA to the TL1431.
Figure 25. Voltage Monitor Figure 26. Delay Timer
Figure 27. Precision Current Limiter Figure 28. Precision Constant-Current Sink
14 Submit Documentation Feedback Copyright © 1991–2012, Texas Instruments Incorporated
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