LM27761
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ZHCSEO7C –OCTOBER 2015–REVISED JANUARY 2017
8 Application and Implementation
注
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The LM27761 low-noise charge-pump voltage converter inverts a positive voltage in the range of 2.7 V to 5.5 V
to a negative output voltage configurable with external gain setting resistors. The device uses four low-cost
capacitors to provide up to 250 mA of output current. The LM27761 operates at a 2-MHz oscillator frequency to
reduce charge-pump output resistance and voltage ripple under heavy loads. With an operating current of only
370 µA and 7-µA typical shutdown current, the LM27761 provides ideal performance for battery-powered
systems.
8.2 Typical Application - Regulated Voltage Inverter
LM27761
VIN
EN
VOUT
C2
4.7 µF
R1
R2
C4
2.2 µF
VFB
C1+
C1-
CPOUT
C3
4.7 µF
C1
1 µF
GND
图 16. LM27761 Typical Application
8.2.1 Design Requirements
Example requirements for typical applications using the LM27761 device are listed in 表 1:
表 1. Design Parameters
DESIGN PARAMETER
Input voltage
EXAMPLE VALUE
2.7 V to 5.5 V
–1.5 V to –5 V
0 mA to 250 mA
2 MHz
Output voltage
Output current
Boost switching frequency
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