LPS3015 View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

LPS3015

High Voltage Input Integrated Switch Step-Down Regulator

Microchip Technology 

4.0 DETAILED DESCRIPTION

4.1 Device Overview

The MCP16301 is a high input voltage step-down

regulator, capable of supplying 600 mA to a regulated

output voltage from 2.0V to 15V. Internally, the trimmed

500 kHz oscillator provides a fixed frequency, while the

Peak Current Mode Control architecture varies the duty

cycle for output voltage regulation. An internal floating

driver is used to turn the high side integrated

N-Channel MOSFET on and off. The power for this

driver is derived from an external boost capacitor

whose energy is supplied from a fixed voltage ranging

between 3.0V and 5.5V, typically the input or output

voltage of the converter. For applications with an output

voltage outside of this range, 12V for example, the

boost capacitor bias can be derived from the output

using a simple Zener diode regulator.

4.1.1 INTERNAL REFERENCE VOLTAGE

VREF

An integrated precise 0.8V reference combined with an

external resistor divider sets the desired converter out-

put voltage. The resistor divider range can vary without

affecting the control system gain. High-value resistors

consume less current, but are more susceptible to

noise.

4.1.2 INTERNAL COMPENSATION

All control system components necessary for stable

operation over the entire device operating range are

integrated, including the error amplifier and inductor

current slope compensation. To add the proper amount

of slope compensation, the inductor value changes

along with the output voltage (see Table 5-1).

4.1.3 EXTERNAL COMPONENTS

External components consist of:

• input capacitor

• output filter (Inductor and Capacitor)

• freewheeling diode

• boost capacitor

• boost blocking diode

• resistor divider.

The selection of the external inductor, output capacitor,

input capacitor and freewheeling diode is dependent

upon the output voltage and the maximum output

current.

MCP16301

4.1.4 ENABLE INPUT

Enable input, (EN), is used to enable and disable the

device. If disabled, the MCP16301 device consumes a

minimal current from the input. Once enabled, the

internal soft start controls the output voltage rate of rise,

preventing high-inrush current and output voltage

overshoot.

4.1.5 SOFT START

The internal reference voltage rate of rise is controlled

during startup, minimizing the output voltage overshoot

and the inrush current.

4.1.6 UNDER VOLTAGE LOCKOUT

An integrated Under Voltage Lockout (UVLO) prevents

the converter from starting until the input voltage is high

enough for normal operation. The converter will typi-

cally start at 3.5V and operate down to 3.0V. Hysteresis

is added to prevent starting and stopping during

startup, as a result of loading the input voltage source.

4.1.7

OVERTEMPERATURE

PROTECTION

Overtemperature protection limits the silicon die

temperature to 150°C by turning the converter off. The

normal switching resumes at 120°C.

© 2011 Microchip Technology Inc.

DS25004A-page 11

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