MPQ4460 – INDUSTRIAL GRADE 2.5A, 4MHz, 36V STEP-DOWN CONVERTER

MPQ4460 Rev1.21

www.MonolithicPower.com

7

12/5/2012

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© 2012 MPS. All Rights Reserved.

OPERATION

The

MPQ4460

is

a

variable

frequency,

non-synchronous,

step-down

switching

regulator with an integrated high-side high

voltage power MOSFET. It provides a single

highly efficient solution with current mode

control for fast loop response and easy

compensation. It features a wide input voltage

range, internal soft-start control and precision

current limiting. Its very low operational

quiescent current makes it suitable for battery

powered applications.

PWM Control

At moderate to high output current, the

MPQ4460 operates in a fixed frequency, peak

current control mode to regulate the output

voltage. A PWM cycle is initiated by the internal

clock. The power MOSFET is turned on and

remains on until its current reaches the value

set by the COMP voltage. When the power

switch is off, it remains off for at least 100ns

before the next cycle starts. If, in one PWM

period, the current in the power MOSFET does

not reach the COMP set current value, the

power MOSFET remains on, saving a turn-off

operation.

--

+

--

+

1.5ms SS

Gm Error Amp

SS

2.6V

5V

COMP

VIN

BST

SW

GND

FREQ

COMP

FB

EN

SS

0V8

REFERENCE UVLO/

THERMAL

SHUTDOWN

INTERNAL

REGULATORS

OSCILLATOR

--

+

SW

--

+

Level

Shift

CLK

Figure 1—Functional Block Diagram