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参数资料
| 型号： | APW7075KAC-TUL |
| 厂商： | Anpec Electronics Corporation |
| 英文描述： | Step-Up Converter and LDO Combo |
| 中文描述： | 升压转换器和稳压器组合 |
| 文件页数： | 16/23页 |
| 文件大小： | 413K |
| 代理商： | APW7075KAC-TUL |
Copyright
ANPEC Electronics Corp.
Rev. A.5 - Aug., 2005
APW 7075
www.anpec.com.tw
16
The APW7075 has an active high enable function. Force
SHDN high (>1.4V) to enable the step-up converter,
SHDN low (<0.3V) to disable the step-up converter
and the device enters shutdown mode. In shutdown
mode, the converter stops switching and all internal
control circuits are turned off, but the output is still
applied by input voltage through the body diode of P-
channel MOSFET, it is about Vin-0.6V. Note that when
the output is applied from the VIN (LDO mode), the
shutdown function is disabled.
Function Description
PFM Control Scheme
The APW7075 features the PFM control scheme to
improve the efficiency during light load. In PFM mode,
the inductor stores the energy during internal N-chan-
nel MOSFET turns on, and the energy is transferred
to output capacitors and load during internal P-chan-
nel MOSFET turns on. If the energy which is charged
to output capacitors exceeds the requirement of load,
the current will reverse from output capacitors to in-
ductor and input capacitors. The PFM comparator com-
pares the source (OUT) and drain (LX) of the internal
P-channel MOSFET. When the current that flows
through the internal P-channel MOSFET is backward
(from OUT to LX), the internal P-channel MOSFET will
be turned off, and the output capacitor supplies the
load and maintains the output voltage. During PFM
mode, the IC switches only as need to serve the load,
reducing the switching frequency and associated
losses in the internal switches and the external
inductor. Some jitter is normal during transition from
PFM to PWM mode; the transition of the PFM to PWM
is dependent on the inductance values, VIN, and VOUT.
The output ripple is higher during PFM operation, a
larger output capacitor can be used to minimize the
output ripple.
Synchronous Rectification
The APW7075 has an internal N-channel and a P-chan-
nel MOSFET, it is no need for external components,
the internal low R
DS(ON)
P-channel MOSFET replaces
the discrete Schottky diode, and it is reducing cost
and board space. During the cycle off time, the P-chan-
nel MOSFET turns on, and the power
dissipation on the P-channel MOSFET is lower than
discrete Schottky diode, thus the conversion efficiency
can be improved.
Shutdown
Soft Start
The APW7075 provides the soft-start function to get
the controlled output voltage rise. When battery volt-
age (<1.8V) is supplied to the device and exceeds the
start-up voltage, the internal N-channel and P-channel
MOSFETs start to switch and pump up the output volt-
age to 1.8V( if the battery voltage is over 1.8V, the
output voltage will equal battery voltage during this
time ), which control circuitry can operate normally .
The soft start controls the rise of internal reference
voltage, when the internal reference voltage exceeds
the feedback voltage which is divided by the resistor
from output voltage, the soft-start circuit will control
the output voltage until the output voltage is in
regulation. The soft-start interval is approximately
30ms.
相关PDF资料 |
PDF描述 |
|---|---|
| APW7075OC-TR | Step-Up Converter and LDO Combo |
| APW7075OC-TRL | Step-Up Converter and LDO Combo |
| APW7075OC-TU | Step-Up Converter and LDO Combo |
| APW7075OC-TUL | Step-Up Converter and LDO Combo |
| APW7077AZBI-TUL | PWM Step-Up DC-DC Converter |
相关代理商/技术参数 |
参数描述 |
|---|---|
| APW7075OC-TR | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:Step-Up Converter and LDO Combo |
| APW7075OC-TRL | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:Step-Up Converter and LDO Combo |
| APW7075OC-TU | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:Step-Up Converter and LDO Combo |
| APW7075OC-TUL | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:Step-Up Converter and LDO Combo |
| APW7077 | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:PWM Step-Up DC-DC Converter |
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