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| 型号： | MCP1252DM-BKLT |
| 厂商： | Microchip Technology |
| 文件页数： | 10/18页 |
| 文件大小： | 0K |
| 描述： | BOARD DEMO FOR MCP1252 |
| 标准包装： | 1 |
| 电流 - 输出 / 通道： | 120mA |
| 输出及类型： | 1，非隔离 |
| 特点： | 短路和热保护，关闭 |
| 输入电压： | 2 ~ 5.5 V |
| 已供物品： | 板 |
| 已用 IC / 零件： | MCP1252 |
MCP1252/3
4.2
Power Efficiency
4.6
Thermal Shutdown
The power efficiency, η , is determined by the mode of
operation. In boost mode, the efficiency is approxi-
mately half of a linear regulator. In buck mode, the effi-
ciency is approximately equal to that of a linear
regulator. The following formulas can be used to
approximate the power efficiency with any significant
amount of output current. At light loads, the quiescent
current of the device must be taken into consideration.
The MCP1252 and MCP1253 feature thermal shut-
down with temperature hysteresis. When the die tem-
perature exceeds 160°C, typically, the device shuts
down. When the die cools by 15°C, typically, the device
automatically turns back on. If high die temperature is
caused by output overload and the load is not removed,
the device will turn on and off, resulting in a pulse out-
put.
EQUATION
5.0
APPLICATIONS
P OUT V O UT × I OU T V OUT
V IN × 2 × I O UT
V IN × 2
η BOOST
= ------------- = ------------------------------------ = ------------------
P IN
The MCP1252 and MCP1253 are inductorless, positive
regulated, charge pump DC/DC converters. A typical
circuit configuration for the fixed output version is
depicted in Figure 5-1. The adjustable version is
P OUT V OU T × I OUT V OU T
η BUCK = = = -------------
------------- --------------------------------
P IN V IN × I OU T V IN
SELECTABLE OUTPUT VOLTAGE
C+
C-
3 V IN
PGOOD
SELECT
7
4.3 Shutdown Mode
Driving SHDN low places the MCP1252 or MCP1253 in
a low power shutdown mode. This disables the charge
pump switches, oscillator and control logic, reducing
the quiescent current to 0.1 μA (typical). The PGOOD
output is in a high-impedance state during shutdown.
4.4 PGOOD Output
The PGOOD output is an open-drain output that sinks
current when the regulator output voltage falls below
C FLY
2.7V to 5.5V
+
C IN
ON
OFF
Shutdown
Control
6
5
MCP1252-33X50
V OUT 2
1
8
SHDN
GND
4
+5.0V ±2.5%
+
R PU C OUT
PGOOD Flag
To PICmicro ?
Microcontroller
C FLY = 1 μF
C IN = 10 μF
C OUT = 10 μF
R PU = 100 k ?
0.93V OUT (typical). The output voltage can either be
fixed when the selectable output device is chosen
(MCP1252-33X50, MCP1253-33X50) or adjustable
from an external resistive divider when the adjustable
device is chosen (MCP1252-ADJ, MCP1253-ADJ). If
FIGURE 5-1: Typical Circuit Configuration
for Fixed Output Device.
ADJUSTABLE OUTPUT VOLTAGE
C+
C-
PGOOD 1
+ C OUT
the regulator output voltage falls below 0.93V OUT (typ-
ical) for less than 200 μsec and then recovers, glitch-
immunity circuits prevent the PGOOD signal from tran-
sitioning low. A 10 k ? to 1 M ? pull-up resistor from
PGOOD to V OUT may be used to provide a logic output.
Connect PGOOD to GND or leave unconnected if not
used.
4.5 Soft-Start and Short-Circuit
Protection
The MCP1252 and MCP1253 features foldback short-
circuit protection. This circuitry provides an internal
soft-start function by limiting in-rush current during
startup and also limits the output current to 200 mA
(typical) if the output is shorted to GND. The internal
soft-start circuitry requires approximately 300 μsec,
C FLY
2.7V to 5.5V
+
C IN
ON
OFF
Shutdown
Control
MCP1252-ADJ
6
V OUT 2
5
3 V IN
7 FB 8
SHDN
GND
4
V OUT = 1.21V (1 + R 1 /R 2 )
+4.0V
R PU
R 1
PGOOD Flag
To PICmicro ?
Microcontroller
R 2
C FLY = 1 μF
C IN = 10 μF
C OUT = 10 μF
R PU = 100 k ?
R 1 = 23.2 k ?
R 2 = 10 k ?
typical with a 5V output, from either initial power-up or
release from shutdown for the output voltage to be in
regulation.
DS21752A-page 10
FIGURE 5-2: Typical Circuit Configuration
for Adjustable Output Device.
? 2002 Microchip Technology Inc.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MCP1252T-33X50I/MS | 功能描述:电荷泵 120mA Regulated RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MCP1252T-ADJI/MS | 功能描述:电荷泵 120mA Regulated Adj RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MCP1253 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Low Noise, Positive-Regulated Charge Pump |
| MCP1253-33X50I/MS | 功能描述:电荷泵 120mA Regulated RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 输出电压:- 1.5 V to - 5.5 V, 3 V to 11 V 输出电流:100 mA 电源电流:1 mA 最大工作温度:+ 70 C 封装 / 箱体:SOIC-8 Narrow 封装:Tube |
| MCP1253-33X50I/MS | 制造商:Microchip Technology Inc 功能描述:DC/DC Charge Pump Converter (DC-DC) IC |
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