317B 查看數據表（PDF） - Linear Technology
零件编号
产品描述 (功能)
生产厂家
317B Datasheet PDF : 16 Pages
| |||
LT1317/LT1317B
APPLICATIONS INFORMATION
LOW-BATTERY DETECTOR
The LT1317’s low-battery detector is a simple PNP input
gain stage with an open collector NPN output. The nega-
tive input of the gain stage is tied internally to a 200mV
±5% reference. The positive input is the LBI pin. Arrange-
ment as a low-battery detector is straightforward.
Figure 11 details hookup. R1 and R2 need only be low
enough in value so that the bias current of the LBI pin
doesn’t cause large errors. For R2, 100k is adequate. The
200mV reference can also be accessed as shown in
Figure 12. The low-battery detector remains active in
shutdown.
R1
LBI
R2
100k
VIN
+
–
LT1317
LBO
3.3V
1M
TO PROCESSOR
200mV
INTERNAL
REFERENCE
GND
1317 F11
R1 = VLB – 200mV
2µA
Figure 11. Setting Low-Battery Detector Trip Point
200k
2N3906
VREF
200mV
+
10k
10µF
VIN
LBO
LT1317
LBI
GND
1317 F12
Figure 12. Accessing 200mV Reference
TYPICAL APPLICATIO S
Single Li-Ion Cell to 3.3V SEPIC Converter
C3
L1A*
1µF
MBR0520
SINGLE
Li-ION
CELL
(2.7V TO
4.2V)
+
C1
47µF
VIN
SW
FB
LT1317
SHDN
VC
GND
33k
3300pF
C1, C2: AVX TPSC476M010
C3: AVX 1206YC106KAT
* COILTRONICS CTX20-1
L1B*
1M
1%
+
604k
1%
VOUT
3.3V
250mA
C2
47µF
1317 TA03
3.3V SEPIC Efficiency
80
75
70
65
60
55
50
1
VIN = 2.7V
VIN = 3.5V
VIN = 4.2V
10
100
LOAD CURRENT (mA)
1000
1317 TA03a
11
Share Link: 