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參數(shù)資料
| 型號： | SP828EK |
| 英文描述： | High Efficiency Voltage Inverters |
| 中文描述： | 高效高壓變頻器 |
| 文件頁數(shù)： | 11/16頁 |
| 文件大?。?/td> | 259K |
| 代理商： | SP828EK |
11
SP828DS/03 SP828/829 High Efficiency Voltage Inverters Copyright 1999 Sipex Corporation
Negative Voltage Converter
The typical operating circuit for the
SP828/829
devices is a negative voltage converter. Refer to
Figure 19
. This circuit is used to obtain the
Typical Performance Characteristics found in
Figures 1
to
18
(unless otherwise noted).
Voltage Inverter with the Load from
V
to V
A designer can find the most common application
for the
SP828/829
devices in
Figure 20
as a
voltage inverter. The only external components
needed are 3 capacitors: the flying capacitor, C1,
the output capacitor, C2, and the bypass capacitor,
C3 (if necessary).
Driving Excessive Loads
The output should never be pulled above ground.
A designer should implement a Schottky diode
(1N5817) from OUT to GND when driving
heavy loads where a higher supply is sourcing
current into OUT. Refer to
Figure 23
for this
circuit connection.
APPLICATION INFORMATION
For the following applications, C1 = C2 = 10
μ
F
for the
SP828
and C1 = C2 = 3.3
μ
F for the
SP829
.
Capacitor Selection
Low ESR capacitors are needed to obtain low
output resistance. Refer to
Table 1
for some
suggested low ESR capacitors. The output
resistance of the
SP828/829
devices is a function
of the ESR of C1 and C2. This output resistance
can be determined by the equation previously
provided in the
Efficiency
section:
R
OUT
≈
4 x (2 x R
SWITCHES
+ ESR
C1
) +
ESR
C2
+
1
f
OSC
x C1
,
where R
is the circuit output resistance,
R
is the internal resistance of the MOSFET
switches, ESR
and ESR
are the ESR of their
respective capacitors, and f
OSC
is the oscillator
frequency. This term with f
is derived from an
ideal switched-capacitor circuit as seen in
Figure 21
.
Minimizing the ESR of C1 and C2 will minimize
the total output resistance and will improve the
efficiency.
Flying Capacitor
Decreasing flying capacitor, C1, values will
increase the output resistance of the
SP828/829
devices while increasing C1 will reduce the
output resistance. There is a point where
increasing C1 will have a negligible effect on the
output resistance due to the the domination of the
output resistance by the internal MOSFET switch
resistance and the total capacitor ESR.
Output Capacitor
Increasing output capacitor, C2, values will
decrease the output ripple voltage. Reducing the
ESR of C2 will reduce both output ripple voltage
and output resistance. If higher output ripple can
be tolerated in designs, smaller capacitance values
for C2 should be used with light loads. The
following equation can be used to calculate the
peak-to-peak ripple voltage:
V
RIPPLE
= 2 x I
OUT
x ESR
C2
+
I
OUT
f
OSC
x C2
.
Input Bypass Capacitor
The bypass capacitor at the input pin will reduce
AC impedance and the impact of any of the
SP828/829
devices' switching noise. It is
recommended that for heavy loads a bypass
capacitor approximately equal to the flying
capacitor, C1, be used. For light loads, the value
of the bypass capacitor can be reduced.
When loading the
SP828/829
devices from IN to
OUT, the input current remains constant
(disregarding any spikes due to internal
switching). Implementing a 0.1
μ
F bypass
capacitor should be sufficient.
When loading the
SP828/829
devices from OUT
to GND, the current from the supply will flow
into the input for half of the cycle and will be zero
for the other half of the cycle. Designers should
implement a large bypass capacitor (C3 = C1)
if the supply has a high AC impedance.
相關PDF資料 |
PDF描述 |
|---|---|
| SP829 | High Efficiency Voltage Inverters |
| SP829EK | High Efficiency Voltage Inverters |
| SP8480 | Monolithic, 12-Bit Data Acquisition System |
| SP8480AP | Monolithic, 12-Bit Data Acquisition System |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| SP829 | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:High Efficiency Voltage Inverters |
| SP829EK | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:High Efficiency Voltage Inverters |
| SP82AL | 制造商:Hubbell Wiring Device-Kellems 功能描述:ALMOND PAINTED STEEL 2 GANG DUPLEX |
| SP82G | 制造商:Hubbell Wiring Device-Kellems 功能描述:GRAY PAINTED STEEL 2 GANG DUPLEX |
| SP83 | 制造商:Hubbell Wiring Device-Kellems 功能描述:3/3/2 SPLITTER, 1 IN 3 OUT |
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