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| 型号： | MCP1624T-I/MC |
| 厂商： | Microchip Technology |
| 文件页数： | 12/28页 |
| 文件大小： | 0K |
| 描述： | IC BOOST SYNC REG PWM/PFM 8DFN |
| 标准包装： | 3,300 |
| 应用： | 转换器，PIC? 微控制器 |
| 输入电压： | 0.8 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 2 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-VFDFN 裸露焊盘 |
| 供应商设备封装： | 8-DFN（2x3） |
| 包装： | 带卷 (TR) |
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MCP1623/24
4.2.2
PWM MODE OPERATION
The MCP1623/24 devices incorporate a true output
In normal PWM operation, the MCP1623/24 operates
as a fixed frequency, synchronous boost converter. The
switching frequency is internally maintained with a
oscillator typically set to 500 kHz. The MCP1623
device will operate in PWM-only mode even during
periods of light load operation. By operating in PWM-
only mode, the output ripple remains low and the
frequency is constant. Operating in fixed PWM mode
results in lower efficiency during light load operation
(when compared to PFM mode (MCP1624).
disconnect feature. With the EN pin pulled low, the
output of the MCP1623/24 is isolated or disconnected
from the input by turning off the integrated P-Channel
switch and removing the switch bulk diode connection.
This removes the DC path typical in boost converters,
which allows the output to be disconnected from the
input. During this mode, less than 1 μA of current is
consumed from the input (battery). True output discon-
nect does not discharge the output; the output voltage
is held up by the external C OUT capacitance.
Lossless current sensing converts the peak current
4.2.6
INTERNAL BIAS
signal to a voltage to sum with the internal slope
compensation. This summed signal is compared to the
voltage error amplifier output to provide a peak current
control command for the PWM signal. The slope
compensation is adaptive to the input and output
voltage. Therefore, the converter provides the proper
amount of slope compensation to ensure stability, but is
not excessive, which causes a loss of phase margin.
The peak current limit is set to 425 mA typical.
The MCP1623/24 gets its start-up bias from V IN . Once
the output exceeds the input, bias comes from the
output. Therefore, once started, operation is
completely independent of V IN . Operation is only
limited by the output power level and the input source
series resistance. Once started, the output will remain
in regulation down to 0.35V typical with 1 mA output
current for low source impedance inputs.
4.2.3
PFM MODE OPERATION
4.2.7
INTERNAL COMPENSATION
The MCP1624 device is capable of operating in normal
PWM mode and PFM mode to maintain high efficiency
at all loads. In PFM mode, the output ripple has a
variable frequency component that changes with the
input voltage and output current. With no load, the
quiescent current draw from the output is typically
19 μA. The PFM mode can be disabled in selected
device options.
PFM operation is initiated if the output load current falls
below an internally programmed threshold. The output
The error amplifier, with its associated compensation
network, completes the closed loop system by
comparing the output voltage to a reference at the
input of the error amplifier, and feeding the amplified
and inverted signal to the control input of the inner
current loop. The compensation network provides
phase leads and lags at appropriate frequencies to
cancel excessive phase lags and leads of the power
circuit. All necessary compensation components and
slope compensation are integrated.
voltage is continuously monitored. When the output
4.2.8
SHORT CIRCUIT PROTECTION
voltage drops below its nominal value, PFM operation
pulses one or several times to bring the output back
into regulation. If the output load current rises above
the upper threshold, the MCP1624 transitions smoothly
into PWM mode.
Unlike most boost converters, the MCP1623/24 allows
its output to be shorted during normal operation. The
internal current limit and overtemperature protection limit
excessive stress and protect the device during periods
of short circuit, overcurrent and overtemperature.
4.2.4
ADJUSTABLE OUTPUT VOLTAGE
4.2.9
LOW NOISE OPERATION
The MCP1623/24 output voltage is adjustable with a
resistor divider over a 2.0V minimum to 5.5V maximum
range. High value resistors are recommended to
minimize quiescent current to keep efficiency high at
light loads.
The MCP1623/24 integrates a low noise anti-ring
switch that damps the oscillations typically observed at
the switch node of a boost converter when operating in
the Discontinuous Inductor Current mode. This
removes the high frequency radiated noise.
4.2.5
ENABLE/OUTPUT DISCONNECT
4.2.10
OVERTEMPERATURE
The enable pin is used to turn the boost converter on
and off. The enable threshold voltage varies with input
voltage. To enable the boost converter, the EN voltage
level must be greater than 90% of the V IN voltage. To
disable the boost converter, the EN voltage must be
less than 20% of the V IN voltage.
DS41420C-page 12
PROTECTION
Overtemperature protection circuitry is integrated in the
MCP1623/24. This circuitry monitors the device junction
temperature and shuts the device off if the junction
temperature exceeds the typical +150 o C threshold. If
this threshold is exceeded, the device will automatically
restart once the junction temperature drops by 10 o C.
The soft start is reset during an overtemperature
condition.
? 2011 Microchip Technology Inc.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MCP16251 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Low Quiescent Current, PFM/PWM Synchronous Boost Regulator |
| MCP16251T-I/CH | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MCP16251T-I/MNY | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MCP16252 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Low Quiescent Current, PFM/PWM Synchronous Boost Regulator |
| MCP16252T-I/CH | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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