MP2363 – 3A, 27V, 365KHz STEP-DOWN CONVERTER

MP2363 Rev. 1.0

www.MonolithicPower.com

5

6/15/2006

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2006 MPS. All Rights Reserved.

OPERATION

The MP2363 is a current-mode step-down

regulator. It regulates an input voltage between

4.75V to 27V down to an output voltage as low as

0.92V, and is able to supply up to 3A of load

current.

The MP2363 uses current-mode control to

regulate the output voltage. The output voltage

is measured at the FB pin through a resistive

voltage divider and amplified through the internal

error amplifier. The output current of the

transconductance error amplifier is presented at

COMP where a network compensates the

regulation control system. The voltage at COMP

is compared to the switch current measured

internally to control the output voltage.

The converter uses an internal N-Channel

MOSFET switch to step-down the input voltage

to the regulated output voltage. Since the

MOSFET requires a gate voltage greater than

the input voltage, a boost capacitor connected

between SW and BS drives the gate. The

capacitor is charged by an internal 5V supply

while SW is low.

An internal 10Ω switch from SW to GND is used

to insure that SW is pulled to GND when SW is

low

to

fully

charge

the

LOCKOUT

COMPARATOR

ERROR

AMPLIFIER

FREQUENCY

FOLDBACK

COMPARATOR

INTERNAL

REGULATORS

1.8V

SLOPE

COMP

CLK

CURRENT

COMPARATOR

CURRENT

SENSE

AMPLIFIER

SHUTDOWN

COMPARATOR

COMP

6

IN 2

EN 7

GND

4

OSCILLATOR

35KHz/

365KHz

S

R

Q

SW

3

BS

1

5V

+

Q

1.2V

+

+

2.54V/

2.33V

+

0.92V

0.35V

+

+

FB

5

--

--

--

--

--

--

SS 8

Figure 1—Functional Block Diagram