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參數(shù)資料
| 型號： | HWD20011EUA |
| 廠商： | Electronic Theatre Controls, Inc. |
| 元件分類： | DC/DC變換器 |
| 英文描述： | High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| 中文描述： | 高效率，低電源電流，結(jié)構緊湊，升壓型DC - DC轉(zhuǎn)換器 |
| 文件頁數(shù)： | 8/13頁 |
| 文件大?。?/td> | 787K |
| 代理商： | HWD20011EUA |
H
As a result, the synchronous rectifier significantly
improves efficiency without the addition of an external
component. Conversion efficiency can be as high as
94%, as shown in the
Typical Operating Characteristics
.
For low-voltage inputs from single cells (Alkaline, NiCd,
or NiMH), use an external Schottky diode such as the
1N5817 to ensure start-up.
V oltage Referenc e
The voltage at REF is nominally +1.30V. REF can
source up to 100μA to external circuits. The reference
maintains excellent load regulation (see
Typical Oper-
ating Characteristics
). A bypass capacitor of 0.1μF is
required for proper operation.
S hutdown
The device enters shutdown when V
SHDN
is low
(V
SHDN
<20% of V
OUT
). For normal operation, drive
SHDN
high (V
SHDN
>80% of V
OUT
) or connect
SHDN
to OUT. During shutdown, the body diode of the P-
channel MOSFET allows current flow from the battery to
the output. V
OUT
falls to approximately V
IN
- 0.6V and
LX remains high impedance. The capacitance and load
at OUT determine the rate at which V
OUT
decays.
Shutdown can be pulled as high as 6V, regardless of
the voltage at OUT.
Current Limit S elec t Pin (HWD20012)
The
HWD20012
allows a selectable inductor current limit
of either 0.5A or 1A. This allows flexibility in designing
for higher current applications or for smaller, compact
designs. Connect CLSEL to OUT for 1A or to GND for
0.5A. CLSEL draws 1.4μA when connected to OUT.
BAT T /Damping S witc h (HWD20012)
The
HWD20012
is designed with an internal damping
switch to minimize ringing at LX. The damping switch
connects an external resistor (R1) across the inductor
when the inductor’s energy is depleted (Figure 2).
Normally, when the energy in the inductor is insufficient
to supply current to the output, the capacitance and
inductance at LX form a resonant circuit that causes
ringing. The ringing continues until the energy is dissi-
pated through the series resistance of the inductor. The
damping switch supplies a path to quickly dissipate this
energy, minimizing the ringing at LX. Damping LX ring-
ing does not reduce V
OUT
ripple, but does reduce EMI.
R1 = 200
works well for most applications while reduc-
ing efficiency by only 1%. Larger R1 values provide less
damping, but have less impact on efficiency. Generally,
lower values of R1 are needed to fully damp LX when
the V
OUT
/V
IN
ratio is high (Figures 2, 3, and 4).
High-Effic ienc y, Low-S upply-Current,
Compac t, S tep-Up DC-DC Converters
8
HWD20012
DAMPING
SWITCH
BATT
R1
200
LX
OUT
22
μ
H
V
IN
0.1
μ
F
47
μ
F
V
OUT
Figure 2. Simplified Diagram of Inductor Damping Switch
2
μ
s/div
V
LX
1V/div
Figure 3. LX Ringing Without Damping Switch
2
μ
s/div
V
LX
1V/div
Figure 4. LX Waveform with Damping Switch (with 200
external resistor)
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| HWD20012 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| HWD20012EUB | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| HWD2001EUA | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters |
| HWD210 | 制造商:NTE Electronics 功能描述: |
| HWD2108 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Dual 105 mW Headphone Amplifier |
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