MCP16301HT-ESLASHCH datasheet(12/38 Pages) MICROCHIP

12 / 38 page

MCP16301/H

DS20005004E-page 14

 2011-2021 Microchip Technology Inc.

FIGURE 4-1:

MCP16301/H Block Diagram.

4.2

Functional Description

4.2.1

STEP-DOWN OR BUCK

CONVERTER

The

MCP16301/H

devices

are

non-synchronous

step-down or buck converters, capable of stepping

input voltages ranging from 4V to 30V (MCP16301) or

36V

(MCP16301H)

down

2.0V

15V,

for

VIN >VOUT.

The integrated high-side switch is used to chop or mod-

ulate the input voltage using a controlled duty cycle for

output voltage regulation. High efficiency is achieved

by using low-resistance integrated switch, low forward

drop diode (Schottky rectifier), low equivalent series

resistance (ESR) capacitors and low DC impedance

(DCR) inductor. When the switch is turned on, a DC

voltage is applied to the inductor (VIN –VOUT),

resulting in a positive linear ramp of inductor current.

When the switch turns off, the applied inductor voltage

is equal to -VOUT, resulting in a negative linear ramp of

inductor current (ignoring the forward drop of the

Schottky diode).

For

steady-state,

continuous

inductor

current

operation, the positive inductor current slope must be

identical to the negative current slope. While operating

in steady state, the switch duty cycle must be equal to

the relationship of VOUT/VIN for constant output voltage

regulation, under the condition that the inductor current

is continuous or never reaches zero. For discontinuous

inductor current operation, the steady-state duty cycle

will be less than VOUT/VIN to maintain voltage

regulation. The average of the chopped input voltage or

SW node voltage is equal to the output voltage, while

the average of the inductor current is equal to the

output current.

FIGURE 4-2:

Step-Down Converter.

Schottky

Diode

COUT

CBOOST

Slope

Comp

PWM

Latch

Overtemp

Precharge

Comp

Amp

CCOMP

RCOMP

Drive

VREG

REF

VREF

OTEMP

Boost

Pre-

charge

500 kHz OSC

VOUT

RSENSE

GND

Boost Diode

VIN

RTOP

RBOT

BOOST

GND

VREF

SHDN all blocks

CIN

Schottky

Diode

COUT

VOUT

VIN

off

IOUT

VOUT

VIN

off

IOUT

VIN

Continuous Inductor Current Mode

Discontinuous Inductor Current Mode

MCP16301HT-E/CH Datasheet(PDF) 12 Page - Microchip Technology

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