RT4722C
Functional Block Diagram
AVIN
UVLO
PVIN
PVIN
Switching
Well
LX3
VO3
ZCD3
SCP3
ENO3
VO3
P3
Pulse
Diming
PWM
Logic
OCP3
Soft-start
VRX3
GM
FB3
RP6
FB3
RP5
N3
LX1
VO1
VR1
1.5MHz
OSC
PVIN1
Switching
Well
VO1
FBS
R1A
VRX’
P1
RP2
FB1
GM
R1B
PWM
Logic
VRX
GM
N1
SCP1
RP1
OCP1
Soft-start
Swire
FB1
Pulse Dimming
PVIN
VRX’
NN1
RDIMP
FB2
RDIMN
GM
OCP2
PWM
Logic
LX2
SCP2
Soft-
start
NN2
VO2
VO2
VO1
Fast Discharge
VO2
VO3
OTP
FD
AGND
PGND1
PGND2
Operation
The RT4722C is a triple channels DC-DC converter
which is designed to provide the power of AMOLED
that can support the input voltage range from 2.9V to
4.5V. The VO1 & VO2 output current can be up to
300mA, and the VO3 output current can be up to 55mA.
The RT4722C uses current mode architecture for the
purpose of high efficiency and high transient response.
The VO1 positive output voltage is produced from the
DC-DC Boost converter and is set at a typical value of
4.6V. When the SWIRE goes high, the positive output
voltage will be enabled with an internal soft-start
process. The VO2 negative output voltage is produced
from the DC-DC Buck-Boost converter and the
negative output voltage range is
1.4V
to
5.4V.
It can
be programmed by external MCU through single wire
(SWIRE pin). The VO3 positive output voltage is
produced from the DC-DC Boost converter and is set
from 5.8V to 7.9V by SWIRE pin. When SWIRE goes
high and VO1 soft-start had finished already, negative
output voltage VO2 will be enabled with an internal
soft-start process.
Copyright © 2017 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS4722C-00
September 2017
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
