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參數(shù)資料
| 型號： | SP6643 |
| 元件分類： | DC/DC變換器 |
| 英文描述： | Single Alkaline Cell, High Efficiency Step-Up DC-DC Converter(單堿性電池，3.3V或可調(diào)電壓,高效步升DC-DC變換器) |
| 中文描述： | 單節(jié)堿性，高效率步細胞型DC - DC轉(zhuǎn)換器（單堿性電池，3.3伏或可調(diào)電壓，高效步升的DC - DC變換器） |
| 文件頁數(shù)： | 12/16頁 |
| 文件大小： | 248K |
| 代理商： | SP6643 |
Rev. 10-6-00
SP6642/6643 High Efficiency Step-Up DC-DC Converter Copyright 2000 Sipex Corporation
12
GND
OUT
0.1
μ
F
FB
LX
V
BATT
22
μ
F
0.1
μ
F
22
μ
F
+3.3V
OUT
μ
H
100
10.85V to
SP6643
PFO
PFI
BATTLO
Figure 23. SP6643 +3.3V Typical Application Circuit
TIMING
LOGIC
T-OFF
T-ON
DRV-P
DRV-N
EN
V
REF
FB
V
BATT
P
V
OUT
LX
V
REF
0.5V
REF
1.0V
V
REF
START
UP
OSC
N
N
0.5V
REF
PFI
PFO
1.0V
BATTLO
SP6643
Figure 22. Internal block diagram of the SP6643
R4
R3
GND
PFI
V
TH
SP6642
Figure 24. Power-Fail Detection Circuitry
Power-Fail Detection Circuitry
The SP6642/6643 devices have an internal
comparator for power-fail detection. This
comparator can detect a loss of power at the
input or output. If the voltage at PFI falls below
614mV, the PFO output sinks current to ground.
Hysteresis at the power-fail input is 1%. The
power-fail monitor's threshold voltage is
determined by two resistors, R3 and R4. Refer
to
Figure 24
. The power-fail monitor threshold
voltage can be set using the following equation:
where R3 and R4 are the resistors in
Figure 24
,
V
is the desired threshold voltage of the power-
fail detector, and V
is the 614mV reference of
the power-fail comparator. Since PFI leakage is
10nA max, select feedback resistor R4 in the
100k
to 1M
.
BATTLO for the SP6643
The SP6643
device has an internal comparator
for low-battery detection. If V
drops below
1V, BATTLO will sink current. BATTLO is an
open-drain output. BATTLO used in conjunction
with the power-fail detection circuitry (PFI/
PFO) will monitor both the input and output
voltages.
Shutdown for the SP6642
A logic LOW at SHDN will drive the SP6642
into a shutdown mode where PFO goes into a
high-impedance state, the internal switching
MOSFET turns off, and the synchronous rectifier
turns off to prevent reverse current from flowing
from the output back to the input. Designers
should note that in shutdown, the output can
drift to one diode drop below V
because
there is still a forward current path through the
R3 = R4 x V
TH
V
PFI
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP6644 | Evaluation Board Manual |
| SP6645UEB | Evaluation Board Manual |
| SP6644EB | Evaluation Board Manual |
| SP6644EU | Single/Dual Alkaline Cell, High Efficiency Step-Up DC-DC Converter |
| SP6645 | Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP6643EU | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Application Note:High Current Output |
| SP6644 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Step-Up DC-DC Converter |
| SP6644_05 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
| SP6644EB | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP6644EU | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Single/Dual Alkaline Cell, High Efficiency Boost DC-DC Regulator |
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