RT8509A
3
DS8509A-00 November 2013
www.richtek.com
©
Copyright 2013 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation.
Function Block Diagram
Operation
The RT8509A is a high-performance step-up DC/DC
converter that provides a regulated and high precision
supply voltage. It incorporates current mode, fixed-
frequency, pulse-width modulation (PWM) circuitry with
a built-in N-Channel power MOSFET to achieve high
efficiency and fast transient response. The device features
an adjustable soft start time using an external soft-start
capacitor to reduce in-rush current.
Soft
Start
Control
and
Driver
Logic
Current
Sense
Protection
+
-
+
-
Slope
Compensation
Oscillator
OVP
LX
OTP
Error Amplifier
V
DD
1.25V
FB
COMP
EN
VIN
VOUT
Summing
Comparator
LX
SS
GND
Clock
