®
RT5021
6 + 3 Channels DC/DC PMU with Li-ion Battery Charger
for CMOS DSC/DV
General Description
The RT5021 is a complete power supply solution for digital
still cameras and other hand held devices. The RT5021 is
composed of a multi-channel DC/DC power converter unit,
a single-cell linear Li-ion battery charger, a charger type
detector, and an I
2
C control interface.
The power converter unit includes one synchronous step-
up converter (CH1), one synchronous step-up/down
converter (CH2), three synchronous step-down converters
(CH3/4/5), two LDOs with input power as low as 1.5V
(CH6/8), one WLED driver in synchronous high-voltage
step-up mode or low-voltage current regulator mode (CH7),
and a keep-alive LDO (CH9) for RTC application. All
converters are internally frequency compensated and
integrate power MOSFETs. The power converter unit
provides complete protection functions : over current,
thermal shutdown, over voltage, and under voltage
protection. RT5021 has a WAKEUP impulse generation
circuitry to monitor VIN or BAT installation event. To fulfill
most of applications, RT5021 has six preset power on/off
sequences.
The battery charger includes Auto Power Path
Management (APPM). No external MOSFETs are required.
The charger can enter sleep mode when power is removed.
Charging tasks are optimized by using a control algorithm
to vary the charge rate, including pre-charge mode, fast
charge mode and constant voltage mode. The charge
current can also be programmed via the I
2
C control
interface. The battery regulation voltage and current can
be adjusted by JEITA standard temperature control or other
schemes set via the I
2
C interface. The internal thermal
feedback circuitry regulates the die temperature to optimize
the charge rate for all ambient temperatures. The charging
task will always be terminated in constant voltage mode
when the charging current reduces to the termination
current of 10% x I
CHG_FAST
. The charger includes under
voltage and over voltage protection for the supply input
voltage, VIN. The charger includes USB charger detection
circuitry via D+ and D- pins of USB interface to detect
USB standard downstream ports (SDP), USB charging
downstream port (CDP), dedicated charger port (DCP),
or Apple/Sony charger ports. RT5021 uses some
indicators to show charger states : two open drain ports
CHG and CHG2, and an interrupt (INT) to immediately notify
the state change.
RT5021 has I
2
C interface to control rich functions of Power
Converter Unit and Charger Unit. The RT5021 is available
in the WQFN-40L 5x5 package.
Simplified Application Circuit
BAT
Adapter/USB
System Power
I C Control
SDA
GND
2
Charger for Battery
Step-Up for Motor
Step-Up/Down for I/O
Step-Down for Core
Step-Down for Memory
Step-Down
LDO
Step-Up for LED Backlight
LDO
LDO for RTC
VIN
SYS
SCL
RT5021
PVD1
VO2
LX3
LX4
LX5
VO6
PVD7
VO8
VRTC
Copyright
©
2013 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS5021-01 April 2013
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
