參數資料
型號： MCP1253
廠商： Microchip Technology Inc.
英文描述： Low Noise, Positive-Regulated Charge Pump
中文描述： 低噪聲，正調節(jié)電荷泵
文件頁數： 10/18頁
文件大?。?/td> 440K
代理商： MCP1253
MCP1252/3
DS21752A-page 10
2002 Microchip Technology Inc.
4.2
Power Efficiency
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.
EQUATION
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
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
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,
typical with a 5V output, from either initial power-up or
release from shutdown for the output voltage to be in
regulation.
4.6
Thermal Shutdown
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.
5.0
APPLICATIONS
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
depicted in Figure 5-2.
FIGURE 5-1:
for Fixed Output Device.
Typical Circuit Configuration
FIGURE 5-2:
for Adjustable Output Device.
Typical Circuit Configuration
η
BOOST
P
P
IN
-------------
V
V
IN
OUT
I
OUT
2
---------------------I
V
V
IN
2
-----------------
=
=
=
η
BUCK
P
P
IN
-------------
V
V
IN
OUT
I
OUT
-------------------I
V
V
IN
-------------
=
=
=
MCP1252-33X50
C+
C
FLY
6
5
C-
V
IN
SHDN
3
7
OFF
Shutdown
Control
ON
+
2.7V to 5.5V
C
IN
GND
4
SELECT
PGOOD
V
OUT
8
1
2
+
C
OUT
R
PU
PGOOD Flag
To PICmicro
Microcontroller
+5.0V ±2.5%
SELECTABLE OUTPUT VOLTAGE
C
FLY
=
1 μF
C
IN
=
10 μF
C
OUT
=
10 μF
R
PU
=
100 k
MCP1252-ADJ
C+
C
FLY
6
5
C-
V
IN
SHDN
3
7
OFF
Shutdown
Control
ON
+
2.7V to 5.5V
C
IN
GND
4
FB
PGOOD
V
OUT
8
1
2
+
C
OUT
R
PU
PGOOD Flag
To PICmicro
Microcontroller
+4.0V
ADJUSTABLE OUTPUT VOLTAGE
R
2
R
1
V
OUT
= 1.21V (1 + R
1
/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
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相關代理商/技術參數
參數描述
MCP1253-33X50I/MS 功能描述:電荷泵 120mA Regulated RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
MCP1253-33X50I/MS 制造商:Microchip Technology Inc 功能描述:DC/DC Charge Pump Converter (DC-DC) IC
MCP1253-ADJI/MS 功能描述:電荷泵 120mA Regulated Adj RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
MCP1253T-33X50I/MS 功能描述:電荷泵 120mA Regulated RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
MCP1253T-ADJI/MS 功能描述:電荷泵 120mA Regulated Adj RoHS:否 制造商:Maxim Integrated 功能:Inverting, Step Up 輸出電壓:- 1.5 V to - 5.5 V, 3 V to 11 V 輸出電流:100 mA 電源電流:1 mA 最大工作溫度:+ 70 C 封裝 / 箱體:SOIC-8 Narrow 封裝:Tube
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