PL9405
High Efficiency 4-Switch Bidirectional Buck-Boost Converter
DS-PL9405-Rev. 1.0
www.powlicon.com
1 of 17
2018-11-26
© Powlicon Inc.
1 Features
Bidirectional single Inductor Buck-Boost Controller
for Step-Up/Step-Down DC/DC Conversion and
battery charge management
Bidirectional buck-boost operation to support
battery charging and discharging using OTG signal
Dynamical programming of input current, Output
current and Output voltage using PWM signal or
analog signal
1 Cell to 6 Cells battery charge management
2V to 32 V wide output range
Comprehensive protection features including
Output Short Protection (OSP), Cycle-by-Cycle
input and output Peak Current Limit, thermal
regulation, thermal shutdown, input UVLO, input
OVP, output OVP etc.
Adjustable Switching Frequency using resistor
Frequency dithering for good EMI performance
Integrated 2-A MOSFET Gate Drivers
Integrated two 9
mΩ
power MOSFETs
Input or Output Average Current Limiting with
stable CC loop
5V/55mA low I
q
LDO to power system MCU
Available in QFN6x6-48 Package
2 Applications
Automotive Start-Stop Systems
Backup Battery and Super capacitor Charging
Industrial PC Power Supplies
USB Power Delivery
Power bank ,HUB
3 Description
PL9405 is a synchronous 4-switch bidirectional
Buck-Boost converter capable of regulating the
output voltage at above or below the input voltage.
PL9405 operates over a wide input voltage range of
3.6 V to 32 V (36 V maximum) to support a variety of
applications. Integrated two 9
mΩ
power MOSFETs.
PL9405 can operate at charger mode for 1, 2, 3, 4, 5
and 6 cells battery charge.
PL9405 employs Constant ON time control in buck,
boost and buck-boost operation modes for superior
load and line regulation. The switching frequency
could be set to 150kHz, 300kHz, 600kHz or 1200kHz
based on different resistor value between FREQ pin
and GND pin. The device also features a
programmable soft-start function and offers all kinds
of protection features including cycle-by-cycle current
limiting, input under voltage lockout (UVLO), output
over voltage protection (OVP), input Over Voltage
Protection, thermal shutdown and output short
protection etc.
VADJ, IADJ pins are used to program output VBUS
voltage and output current limit at battery discharging
mode when OTG is high, which makes PL9405 an
excellent option for USB Power Delivery (PD)
application. PL9405 provides voltage control loop,
constant current loop, thermal regulation loop, battery
temperature sensing, which makes it a perfect
solution for batter charge management.
4 Typical Application Schematic
Fig. 1 Application Schematic
VBAT
SW1
SW2
SW1
D1
AGND
CSN1
CSP1
BST1
BST2
SW2
COMP
VDD
VSET
BRCOM
LDO
IREF
LG2
HG2
CSN2
CSP2
FB2
VBAT
EN
OTG
STAT
VREG
VCC
EN
OTG
STAT
VREF
IADJ
I-PWM
VADJ
V-PWM
RCS1
RCS2
CELLS
FREQ
VBUS
TS
TS
VBUS
PGND
PL9405
DS-PL9405-Rev. 1.0
www.powlicon.com
2 of 17
2018-11-26
© Powlicon Inc.
5 Pin Configuration and Functions
48
47
VSET
CSN1
D1
43 42 41
D1
D1
PGND
SW1
13
14
15 16 17 18 19
VREF
7
6
5
4
CSP1
VBAT
3
2
1
D1
D1
BST1
D1
25
29
30
31
32
BST2
SW2
PGND
CSP2
STAT
4446 45
BRCOM
LDO
PGND
IADJ
CELLS
8
26
CSN2
D1
AGND
20
LG2
HG2
27
28
VBUS
IREF
EN
9
10
11
12
21 22 23 24
33
34
35
36
39 38 3740
PGND
PGND
PGND
PGND
VCC
SW1
SW1
SW1
VREG
FREQ
COMP
FB2
OTG
TS
VDD
VADJ
D1 SW1
PGND
Fig. 2 Pin-Function (QFN6X6-48)
Pin
Description
Number
Name
1
BST1
Boost pin for high side MOSFET driver1.
2,43,44,
45,46,4
7,48
D1
Power node of VBAT. Connect to BAT input port. Work as the power output of
the converter when in charging mode, and power input in discharging mode.
3
VBAT
Connect to the VBUS rail.
4
CSP1
The positive input of input current sense.
5
CSN1
The minus input of input current sense.
6
EN
Logic High will enable the converter. Logic Low will disable the whole PL9405
except LDO. Only LDO is working to power system MCU when EN is low.
7,30,
37,38,3
9,40,41
PGND
Power ground.
8
CELLS
Connect a resistor divider between VDD and GND to program battery cells.
9
OTG
Connect OTG to 0 to set PL9405 in battery charging mode. Connect OTG to
LDO to set PL9405 in battery discharging mode.
10
TS
Batter temperature sense
11
VDD
5.4V power supply for PL9405 control core.
12
VADJ
Connect a 0-2V analog voltage or a PWM signal to program voltage reference
on VREF pin. Connect this pin to VDD will force VREF to constant 2V.