RT7255
Function Block Diagram
BOOT
V
IN
PVCC
Reg
VIBIAS
V
REF
UGATE
OC
UV & OV
GND SW
PVCC
SW
SS
FB
V
IN
SW
On-Time
Ripple
Gen.
+
+
-
Comparator
Min.
Off
PVCC
VIN
Control
Driver
LGATE
SW
GND
PGOOD
PWRGN
EN
EN
Operation
The RT7255 is a synchronous step-down converter
with advanced constant on-time control mode. Using
the ACOT control mode can reduce the output
capacitance and fast transient response. It can
minimize the component size without additional
external compensation network.
Current Protection
When the junction temperature exceeds the OTP
The inductor current is monitored via the internal
switches cycle-by-cycle. Once the output voltage drops
under UV threshold, the RT7255 will enter hiccup
mode.
threshold value, the IC will shut down the switching
operation. Once the junction temperature cools down
and is lower than the OTP lower threshold, the
converter will autocratically resume switching.
UVLO Protection
To protect the chip from operating at insufficient supply
voltage, the UVLO is needed. When the input voltage
of VIN is lower than the UVLO falling threshold voltage,
the device will be lockout.
Thermal Shutdown
Copyright © 2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS7255-01
November 2017
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
