Texas Instruments Dual Source USB AC Li Chemistry Charger IC for Portable Applications LM3658SD-AEV/NOPB LM3658SD-AEV/NOPB 데이터 시트
제품 코드
LM3658SD-AEV/NOPB
I
CHG
=
K
ISET
R
ISET
Jumper Functions
4
Jumper Functions
describes the functionality associated with each jumper found on the LM3658 evaluation board.
Table 1. Jumper Functions
Jumper Name
Default Position
Jumper Functionality
R8
Jumper in place
Connects 10 k
Ω
from T
S
to GND pins
R7
Jumper in place
Connects 5 k
Ω
from I
SET
to GND pins
R6
Open
Connects 10 k
Ω
from I
SET
to GND pins
R5
Open
Connects 25 k
Ω
from I
SET
to GND pins
BATT
Jumper in place
Provides LED bias from BATT pin
CHG-IN
Open
Provides LED bias from CHG-IN pin
EN
Jumper in place
Shorts EN_b pin to GND, enabling charging
DISBL
Jumper to CHG-IN
Connects EN_b pullup resistor to CHG-IN or USB
PWR
I
USB
Jumper in place
Shorts USB_sel to GND, setting USB current to 90 mA
5
Detailed Operation of the Evaluation Board
The LM3658 is capable of accepting charge from either an AC adaptor or a USB port. When both are
connected at the same time, the LM3658 will choose the AC adaptor as the power source.
connected at the same time, the LM3658 will choose the AC adaptor as the power source.
5.1
Charging from AC Adaptor
When the LM3658 is accepting charge from the AC adaptor, the “I
SET
” pin is used to program the full-rate
charge current. On the evaluation board, there is space for three separate external resistors, providing up
to seven different selections for charge current. Charge current can be calculated using this equation:
to seven different selections for charge current. Charge current can be calculated using this equation:
Where K
ISET
= 2500. The evaluation board is assembled with the following resistors.
I
SET
Resistor
Value (k
Ω
)
Charge Current (mA)
R5
25
100
R6
10
250
R7
5
500
5.2
Charging from USB Port
When the LM3658 is accepting charge from the USB port, the “USB_sel” pin sets the full-rate charge
current, not the “I
current, not the “I
SET
” pin. Pulling the “USB_sel” pin low will set the charge current to 100 mA; pulling this
pin high will set it to 500 mA. On the LM3658 evaluation board, a 10 k
Ω
resistor pulls this pin high to the
“USB
PWR
” voltage. By placing a jumper on I
USB
, the pin is pulled low to ground.
5.3
Enabling/Disabling the LM3658
The “EN_b” pin is used to enable and disable the LM3658. Pulling this pin low by placing a jumper on EN
enables the LM3658. Pulling this pin high through the 10 k
enables the LM3658. Pulling this pin high through the 10 k
Ω
resistor to the “CHG-IN” voltage disables the
LM3658 on the evaluation board.
2
AN-1517 LM3658 Evaluation Kit
SNVA181E – September 2006 – Revised April 2013
Copyright © 2006–2013, Texas Instruments Incorporated