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參數(shù)資料
| 型號(hào)： | ADP1110 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Micropower, Step-Up/Step-Down Switching Regulator(微功耗,可調(diào)/固定輸出,步升/步降開關(guān)穩(wěn)壓器) |
| 中文描述： | 微功耗，降壓型開關(guān)穩(wěn)壓器（微功耗，可調(diào)/固定輸出，步升/步降開關(guān)穩(wěn)壓器） |
| 文件頁數(shù)： | 9/16頁 |
| 文件大小： | 370K |
| 代理商： | ADP1110 |
ADP1110
–9–
REV. 0
about 30 mV, which indicates an ESR of 0.06
. Figure 18
shows an OS-CON 16–volt capacitor in the same circuit, and
ESR is only 0.02
.
10
0%
100
90
1μs
50mV
Figure 16. Aluminum Electrolytic
10
0%
100
90
1μs
50mV
Figure 17. Tantalum Electrolytic
10
0%
100
90
1μs
50mV
Figure 18. OS-CON Capacitor
If low output ripple is important, the user should consider the
ADP3000. Because this device switches at 400 kHz, lower peak
current can be used. Also, the higher switching frequency
simplifies the design of the output filter. Consult the ADP3000
data sheet for additional details.
DIODE SELECTION
In specifying a diode, consideration must be given to speed,
forward voltage drop and reverse leakage current. When the
ADP1110 switch turns off, the diode must turn on rapidly if
high efficiency is to be maintained. Shottky rectifiers, as well as
fast signal diodes such as the 1N4148, are appropriate. The
forward voltage of the diode represents power that is not
delivered to the load, so V
F
must also be minimized. Again,
Schottky diodes are recommended. Leakage current is especially
important in low-current applications, where the leakage can be
a significant percentage of the total quiescent current.
For most circuits, the 1N5818 is a suitable companion to the
ADP1110. This diode has a V
F
of 0.5 V at 1 A, 4
μ
A to 10
μ
A
leakage, and fast turn-on and turn-off times. A surface mount
version, the MBRS130LT3, is also available.
For switch currents of 100 mA or less, a Shottky diode such as
the BAT85 provides a V
F
of 0.8 V at 100 mA and leakage less
than 1
μ
A. A similar device, the BAT54, is available in a SOT23
package. Even lower leakage, in the 1 nA to 5 nA range, can be
obtained with a 1N4148 signal diode.
General purpose rectifiers, such as the 1N4001, are not suitable
for ADP1110 circuits. These devices, which have turn-on times
of 10
μ
s or more, are too slow for switching power supply
applications. Using such a diode “just to get started” will result
in wasted time and effort. Even if an ADP1110 circuit appears
to function with a 1N4001, the resulting performance will not
be indicative of the circuit performance when the correct diode
is used.
CIRCUIT OPERATION, STEP-UP (BOOST) MODE
In boost mode, the ADP1110 produces an output voltage that is
higher than the input voltage. For example, +5 V can be derived
from one alkaline cell (+1.5 V), or +12 V can be generated from
a +5 V logic power supply.
Figure 19 shows an ADP1110 configured for step-up operation.
The collector of the internal power switch is connected to the
output side of the inductor, while the emitter is connected to
GND. When the switch turns on, pin SW1 is pulled near
ground. This action forces a voltage across L1 equal to V
IN
–
V
CE(SAT),
and current begins to flow through L1. This current
reaches a final value (ignoring second-order effects) of:
I
PEAK
V
IN
–
V
CE
(
SAT
)
L
10
μ
s
where 10
μ
s is the ADP1110 switch’s “on” time.
I
LIM
V
IN
SW1
SW2
4
FB
GND
5
ADP1110
L1
C
1
R1
R2
D1
8
1
2
3
V
IN
V
OUT
R3*
*OPTIONAL
Figure 19. Step-Up Mode Operation
When the switch turns off, the magnetic field collapses. The
polarity across the inductor changes, current begins to flow
through D1 into the load, and the output voltage is driven above
the input voltage.
The output voltage is fed back to the ADP1110 via resistors R1
and R2. When the voltage at pin FB falls below 220 mV, SW1
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ADP1111AR-12 | Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V |
| ADP1111 | PRECISION SEMICONDUCTOR PRESSURE SENSOR |
| ADP1111AR-33 | Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V |
| ADP1111AR-5 | Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V |
| ADP1111AR | Micropower, Step-Up/Step-Down SW Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ADP1110AN | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADP1110AN-12 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADP1110AN-3.3 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
| ADP1110AN-33 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Micropower, Step-Up/Step-Down Switching Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V |
| ADP1110AN-5 | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
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