LP28400 Datasheet, PDF (3/17 Pages) Lowpower Semiconductor inc – Programmable Charge Current Up to 3000mA

Preliminary Datasheet
LP28400
Pin Description
PIN
PIN
NO.
DESCRIPTION
CMS
1
Connect to common source of Nch ACFET and reverse blocking Nch RBFET. Place 4K resistor from
CMS pin to the common source of ACFET and RBFET to control the turn-on speed.
ACDRV 2
AC adapter to system switch driver output.
AVCC 3
IC power supply of internal bias. Put 1uF MLCC from AVCC to AGND. Add 10Ω resistor to filter the noise
of power line.
VREF 4
3.3V reference output. A 1uF MLCC is placed from VREF to GND to make it stable.
TS
5
NTC resistor connection.
ISET
6
Fast charge current set pin.
CELL 7
Cell selection pin. Set CELL pin LOW or floating for 2-cell, HIGH for 1-cell.
STAT 8
Open-Drain Charge Status Output.
SRN
9
Charge current sense negative input.
SRP
Charge current sense positive input. A 0.1-uF is recommended for common mode filtering from SRP to
10
AGND. A 0.1uF is placed from SRP to SRN for differential mode filtering.
GND
11 Power ground.
REGN 12 5V power supply output, Bypass 1uF MLCC to AGND.
Switching node, charge current output inductor connection. Connect a 47-nF BS capacitor from SW
SW
13.14
to BS.
PVCC 15.16 IC power supply of power device of Charger. Put 10uF MLCC from PVCC to PGND.
BS
17 Boostrap pin. Place a 0.047u-F MLCC from SW to BS.
BATDRV 18
Battery discharge MOSFET gate driver output. Connect a 1kohm resistor to the gate of the P-channel
power MOSFET(BATFET). Connect the source of the BATFET to the system load voltage node.
Connect the drain of the BATFET to the battery pack positive node. The internal
gate drive is asymmetrical to allow a quick turn-off and slower turn-on. The internal
break-before-make logic with respect to ACDRV. There is an internal 50k pull-down resistor from
BATDRV to ground.
ACN
Adaptor current sense resistor negative input. A 0.1-uF from ACN to AGND is recommended for common
19
mode filtering. A 0.1uF is placed from ACN to ACP for differential mode filtering.
ACP
Adaptor current sense resistor positive input. A 0.1-uF from ACP to AGND is recommended for common
20
mode filtering. A 0.1uF is placed from ACN to ACP for differential mode filtering.
LP28400-00 Version 1.0 May.-2013 Email: [e-mail] www.lowpowersemi.com Page 3 of 17