RT7255
Function Block Diagram
BOOT
V
IN
PVCC
Reg
Min.
Off
PVCC
VIN
SW
VIBIAS
V
REF
UGATE
LGATE
Control
Driver
OC
UV & OV
PVCC
GND
GND SW
Ripple
Gen.
SW
PGOOD
+
PWRGN
SS
FB
+
-
V
IN
Comparator
On-Time
EN
EN
SW
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.
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
Current Protection
When the junction temperature exceeds the OTP
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.
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.
Copyright © 2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS7255-01 November 2017
www.richtek.com
3
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