RT6219
Functional Block Diagram
VCC
VBYP
V
CC
POR &
Reference
Soft-Start
V
CC
Switch-Over
On-Time
One shot
Min off Time
V
IN
BOOT
FB
V
REF
V
FB
+
+
-
Gate
Control
Logic
SW
V
CC
EN
PGND
SW
V
OC
+
-
OCP
PGOOD
125% x V
REF
-
+
OVP
-
+
Fault
Logic
POK
58% x V
REF
+
-
PGND
91.5% x V
REF
UVP
V
CC
V
CC
Regulator
VIN
Operation
Overall
The RT6219 is a synchronous step-down converter with
advanced constant on-time control mode. Using the
ACOT
TM
control mode can reduce the output capacitance
and provide fast transient response. It can minimize the
component size without additional external compensation
network.
Internal VCC Regulator
The regulator provides 5V power to supply the internal
control circuit. Connecting a 2.2μF ceramic capacitor for
decoupling and stability is required.
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 internal setting
and the duration is around 1.5ms.
VCC Switch-Over
The internal regulator output will switch over to VBYP if
VBYP level is higher than 4.6V.
Power Off
There is an internal discharging circuit to discharge the
residual charge of output capacitor when converter is power
off.
OCP
The inductor valley current is monitored cycle-by-cycle
via the internal swiches, preventing an on-time until the
current drops below the current limit.
Power Good
After soft-start is finished, the power good output goes
high. The PGOOD pin is an open-drain output.
Copyright
©
2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS6219-06 January 2018
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
