RT2810A/B
Function Block Diagram
PVCC
BOOT
POR &
Reg
EN
Min.
Off-Time
PVCC
VIN
VBIAS
V
REF
UGATE
LGATE
OC
Control
Driver
ZC
SW
UV & OV
PVCC
GND
Ripple
Gen.
6µA
+
+
-
Comparator
SS
PGOOD
FB
0.9 V
REF
+
-
V
IN
Comparator
FB
On-Time
Operation
Current Protection
The RT2810A/B is a synchronous step-down converter
with advanced Constant On-Time control mode. Using the
ACOTTM control mode can reduce the output capacitance
and fast transient response. It can minimize the component
size without additional external compensation network.
The inductor current is monitored via the internal switches
cycle-by-cycle. Once the output voltage drops under UV
threshold, the RT2810A/B will enter hiccup mode or latch
off mode.
Power Good
UVLO Protection
After soft-start has finished, the power good function will
be activated. The PGOOD pin is an open-drain output. If
the FB voltage is lower than 80% VREF or higher than
120% VREF, the PGOOD pin will be pulled low.
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.
PVCC
Thermal Shutdown
The regulator provides 5V power to supply the internal
control circuit. 1μF ceramic capacitor for decoupling and
stability is required.
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.
Soft-Start
In order to prevent the converter output voltage from
overshooting during the startup period, the soft-start
function is necessary. The soft-start time is adjustable
by an external capacitor.
Copyright 2016 Richtek Technology Corporation. All rights reserved.
©
is a registered trademark of Richtek Technology Corporation.
DS2810A/B-06 November 2016
www.richtek.com
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