MP2117

– 1.25MHZ, 2.2A SYNCHRONROUS STEP-DOWN SWITCHER

END OF LIFE, REFER TO MP1605

MP2117 Rev. 0.92

www.MonolithicPower.com

7

6/20/2022

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OPERATION

Figure 1

—Functional Block Diagram

The MP2117 is a 1.25MHz fixed frequency

current mode synchronous step-down switcher.

The MP2117 is optimized for low voltage, Li-Ion

battery

powered

applications

where

high

efficiency and small size are critical. The MP2117

can provide up to 2.2A continuous load current

from a 2.5V to 6V input voltage.

The MP2117 uses an external resistor divider to

set the switcher output voltage from 0.6V to 6V.

2.2A Step-Down Switcher

The switcher integrates both a main switch and a

synchronous

rectifier,

which

provides

high

efficiency and eliminates an external Schottky

diode.

The duty cycle D of a step-down switcher is

defined as:

OUT

ON

OSC

IN

V

D

T

f

100%

100%

V

=









Where TON is the main switch on time and fOSC is

the oscillator frequency (1.25MHz).

Current Mode PWM Control

Slope compensated current mode PWM control

provides stable switching and cycle-by-cycle

current

limiting

for

superior

load

and

line

response in addition to protection of the internal

main switch and synchronous rectifier. The

MP2117

switches

at

a

constant

frequency

(1.25MHz) and regulates the output voltage.

During

each

cycle

the

PWM

comparator