3
AN1457.0
May 5, 2009
Description of Jumper Settings
JP1 -
Connects the EN pin to a pull-up voltage or GND. The
pull-up voltage is either the BAT voltage (when a shunt is
installed on JP3) or an external 3.3V power source (when
the shunt on JP3 is removed and a +3.3V supply is
connected to pin 1(at the right) of JP3). If there is no shunt
installed on JP1, the EN pin is internally pulled down to logic
LOW, which enables the charger. If a shunt is installed
across the two jumper pins labeled as “Enable”, the EN pin
is driven to logic LOW and the charger is enabled, same as
floating. If the shunt is installed across the two jumper pins
labeled as “Disable” and the pull-up voltage is above 2V, the
EN pin is driven to logic HIGH, which disables the charger.
JP2 -
A shunt installed on JP2 connects the input source from
connector J1 to the circuit if input current measurement is not
needed. The shunt can be replaced by a current meter if input
current measurement is needed, as shown in Figure 1.
JP3 -
Selects the power source for logic pull-up and the LED
supply. If a shunt is installed, the BAT voltage is selected as
the power source. If the shunt is removed, an external power
supply of +3.3V can be connected from Pin 1 (at the right) to
GND to provide the pull-up and LED supply power. The
purpose is to exclude the extra current through the charger
when characterizing small currents, such as EOC and
quiescent currents.
JP4 -
Connect a 243k resistor from IMIN pin to GND for
50mA EOC current.
JP5 -
Connect a 20k resistor from IREF to GND for 0.6A
charge current.
JP6 -
A shunt installed on JP6 connects the BAT pin to the
output connector J2 if output current measurement is not
needed. The shunt can be replaced by a current meter if
output current measurement is needed as shown in Figure 1.
JP7 -
Parallels an additional 20k resistor to the IREF pin
(total RICDL = 10k), the charge current will be increased to
1.2A.
TABLE 1. JUMPER SETTING SUMMARY
JUMPER
POSITION
FUNCTION
JP1
Shunt on Disable
Charger disabled
Shunt on Enable
Charger enabled
Shunt not installed Charger enabled
JP2
Shunt installed
Connects input source at J1 to VIN
pin
JP3
Shunt installed
Select BAT as the pull-up source
JP4
Shunt installed
Sets EOC current to 50mA
JP5
Shunt installed
Sets charging current to 0.6A, if
shunt on JP7 is not installed
JP6
Shunt installed
Connects BAT to J2
JP7
Shunt installed
Sets charging current to 1.2A, if
shunt on JP5 is also installed
Application Note 1457
