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参数资料
| 型号： | APW7077AZBI-TRL |
| 厂商： | Anpec Electronics Corporation |
| 元件分类： | DC/DC变换器 |
| 英文描述： | PWM Step-Up DC-DC Converter |
| 中文描述： | PWM升压型DC - DC转换器 |
| 文件页数： | 12/21页 |
| 文件大小： | 444K |
| 代理商： | APW7077AZBI-TRL |
Copyright
ANPEC Electronics Corp.
Rev. A.4 - S ep, 2005
APW 7077/ A
www.anpec.com.tw
12
1.0V
)
R1
R2
(1
V
OUT
×
+
=
To avoid the thermal noise from feedback resistor,
(R
1
+R
2
) resistance smaller than 1M
and 1% variation
is recommended.
Soft Start
There is a soft start function is integration in
APW7077/A series to avoid the over shooting when
power on. When power is applied to the device, the
soft start circuit first pumps up the output voltage to
let V
DD
(or V
OUT
) approximately 1.65V at a fixed duty
cycle 50%. This is the voltage level at which the
controller can operate normally. When supply voltage
more than 1.65V the internal reference voltage will be
inductor current is higher than the output current, then
sustains the output voltage until the next switching
cycle.
As the load current is decreased, the switch transistor
turns on for a shorter duty cycle. Under the light load
condition, the controller will skip switching cycles to
reduce power consumption, so that high efficiency is
maintained at light loads.
Fixed Output Voltage (for APW7077 only)
The APW7077 V
OUT
is set by an integrate feedback
resistor network. This is trimmed to a selected voltage
3.3 V or 5.0 V with an accuracy of +/-2.5%.
Setting Output Voltage (for APW7077A only)
For APW7077A, the output voltage is adjustable. The
output voltage is set using the FB pin and a resistor
divider connected to the output as shown in the typical
operating circuit. The internal reference voltage is 1.0V
with 2% variation, so the ratio of the feedback resistors
sets the output voltage according to the following
equation:
Function Description ( Cont.)
Operation (Cont.)
ramp up to let output voltage reach to setting voltage
without over shooting issue whenever heavy load or
light load condition. The soft start time 25ms is
setting by internal circuit.
Oscillator
The oscillator frequency is internally set to 300 kHz at
an accuracy of +/-10% and with low temperature
coefficient of 3.3%/°C.
Enable/Disable Operation
The APW7077/A series offer IC shutdown mode by chip
enable pin (CE pin) to reduce current consumption.
When voltage at pin CE is greater than 1.2 V, the
chip will be enabled, which means the controller is
in normal operation. When voltage at pin CE is less
than 0.7 V, the chip is disabled, which means IC is
shutdown and quiescent current become 1uA.
The CE pin pull high to V
DD
(or V
OUT
) by internal resistor,
and this resistance is greater than 1M
.
So this chip
will enable normally when CE pin floating.
Important: DO NOT apply a voltage between 0.7V
to 1.2 V to pin CE as this is the CE pin’s hysteresis
voltage range. Clearly defined output states can
only be obtained by applying voltage out of this
range.
Compensation
The device is designed to operate in continuous
conduction mode. An internal compensation circuit
was designed to guarantee stability over the full
input/output voltage and full output load range.
Step–up Converter Operating Mode
The step–up DC–DC controller is designed to operate
in continuous conduction mode (CCM) or discontinuous
conduction mode (DCM).
For a step up converter in a CCM, the duty cycle D is
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相关代理商/技术参数 |
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|---|---|
| APW7077AZBI-TU | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:PWM Step-Up DC-DC Converter |
| APW7077AZBI-TUL | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:PWM Step-Up DC-DC Converter |
| APW7077RBI-TR | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:PWM Step-Up DC-DC Converter |
| APW7077RBI-TRL | 制造商:ANPEC 制造商全称:Anpec Electronics Coropration 功能描述:PWM Step-Up DC-DC Converter |
| APW7077RBI-TU | 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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