MP2467 – 2.5A, 36V, 500KHz STEP-DOWN CONVERTER

MP2467 Rev. 1.1

www.MonolithicPower.com

7

1/25/2010

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BLOCK DIAGRAM

--

+

--

+

1.5ms SS

Error Amp

SS

2.6V

COMP

ISW

VIN

BST

SW

R1

R2

GND

COMP

FB

EN

SS

0V8

REFERENCE UVLO/

THERMAL

SHUTDOWN

INTERNAL

REGULATORS

BOOTSTRAP

REGULATOR

RSET

500KHz

OSCILLATOR

2

6

4

3

5

7

8

1

Figure 1—Functional Block Diagram

OPERATION

The

MP2467

is

a

fixed

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.

The MP2467 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 200ns 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.