RT5047

Copyright © 2017 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

DS5047-02

July

2017

www.richtek.com

3

Operation

The RT5047 integrates a current mode boost converter

and linear regulator. Use the SEL pin to control the

LNB voltage and the boost converter track is at least

greater 850mV than LNB voltage. The boost converter

is the high efficiency PWM architecture with 700kHz

operation frequency. The linear regulator has the

capability to source current up to 550mA during

continuous operation. All the loop compensation,

current sensing, and slope compensation functions are

provided internally.

OCP

Both the boost converter and the linear regulator have

independent current limit. In the boost converter

(OCP1),

this

is

achieved

through

cycle-by-cycle

internal current limit (typ. 3A). In the linear regulator

(OCP2), when the linear regulator exceeds OCP more

than 48ms, the LNB output will be disabled and re-start

after 1.8s.

Tone Circuit

This circuit is used for tone generation. Use the TONE

pin to control output amplitude of LNB.

OTP

When the junction temperature reaches the critical

temperature (typically 150

C), the boost converter and

the linear regulator are immediately disabled.

UVLO

The UVLO circuit compares the VIN with the UVLO

threshold (7.7V rising typically) to ensure that the input

voltage is high enough for reliable operation. The

350mV (typ.) hysteresis prevents supply transients

from causing a shutdown.

PWM Controller

The loop compensation, current sensing, and slope

compensation functions are provided internally.