Datasheet

I
CHG
=
K
ISET
R
ISET
Jumper Functions www.ti.com
4 Jumper Functions
Table 1 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 kΩ from T
S
to GND pins
R7 Jumper in place Connects 5 kΩ from I
SET
to GND pins
R6 Open Connects 10 kΩ from I
SET
to GND pins
R5 Open Connects 25 kΩ 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.
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:
Where K
ISET
= 2500. The evaluation board is assembled with the following resistors.
I
SET
Resistor Value (kΩ) 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
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 kΩ 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 kΩ 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
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