MIC2141

Micropower Boost Converter

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (

December 2006

1

M9999-122006

General Description

The MIC2141 is a micropower boost switching regulator

that can operate from 3- or 4-cell nickel-metal-hydride

batteries or a single Li-ion cell. This regulator employs a

constant 330kHz, fixed 18% duty-cycle, gated-oscillator

architecture.

The MIC2141 can be used in applications where the

output voltage must be dynamically adjusted. The device

features

a

control

signal

input

which

is

used

to

proportionally adjust the output voltage. The control signal

input has a gain of 6, allowing a 0.8V to 3.6V control signal

to vary a 4.8V to 22V output.

The MIC2141 requires only three external components to

operate and is available in a tiny 5-pin SOT-23 package for

space and power-sensitive portable applications. The

MIC2141 draws only 70µA of quiescent current and can

operate with an efficiency exceeding 85%.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• Implements low-power boost, SEPIC, or flyback

• 2.2V to 14V input voltage

• 330kHz switching frequency

• <2µA shutdown current

• 70µA quiescent current

• 1.24V bandgap reference

• Typical output current 1mA to 10mA

• SOT23-5 package

Applications

• LCD bias supply

• CCD digital camera supply

___________________________________________________________________________________________________________

Typical Application

MIC2141

Variable

V

OUT

V

(from DAC)

10µF

10µH

15

2

34

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0

5

10

15

20

25

V

Control Voltage

vs. Output Voltage

DAC-Controlled LCD Bias Voltage Supply