BQ24081 Datasheet, PDF (2/10 Pages) Texas Instruments – bq24081EVM 1-A Single-Chip Li-Ion and Li-Pol Charge Management IC Evaluation Module

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Test Summary
1.2 Background
The bq24081 is a highly integrated and flexible Li-Ion linear charge device targeted at space-limited
charger applications. It offers an integrated power FET and current sensor, high-accuracy current and
voltage regulation, charge status, and charge termination, in a single monolithic device. An external
resistor sets the magnitude of the charge current.
The bq24081 charges the battery in three phases: conditioning, constant current, and constant voltage.
Charge is terminated based on minimum current. An internal charge timer provides a backup safety for
charge termination. The bq24081 automatically restarts the charge if the battery voltage falls below an
internal threshold. The bq24081 automatically enters sleep mode when the input supply is removed.
1.3 Performance Specification Summary
V_I(DC)
I_O(CHG)
SPECIFICATION
Supply voltage range
Battery charge current⁽¹⁾
Power dissipation
TEST CONDITIONS
I_(CHG) x (V_(DC+) - V_(BAT+))
MIN
V_(REG) + 0.5
TYP
MAX UNIT
5
5.5
V
0.7
1
A
1.5
W
(1) _{This input voltage maximum is a function of the maximum allowable power dissipation on the device. The current level is}
programmed for 0.7 A. If the programmed charge is changed, then the maximum input voltage needs to be adjusted.
P_MAX(IC) = 1.5 W = I_(CHG) (V_(DC+) – V_(BAT+)). The device has a maximum recommended operation of 6.5 Vdc.
2 Test Summary
This section shows the test setups used, and the tests performed, in evaluating the EVM. See the
bq24081 datasheet (SLUS687) for complete details on operation and specifications for the charger device.
2.1 Test Setup
The bq24081 EVM board requires a regulated 5-Vdc, 1-A power source, to provide input power and a
single-cell Li-Ion or Li-Pol battery pack.
The test setup connections and jumper setting selections are configured for a stand-alone evaluation but
can be changed to interface with external hardware such as a microcontroller.
Jack
J1–DC+
J1–DC-
J2–BAT+
J2–BAT-
J2–TS
J2–BAT-
JMP1–STAT1
JMP2–STAT2
JMP3–TE
Table 1. I/O and Jumper Connections⁽¹⁾
CONNECTION
Power supply positive connection, preset to 5.0-VDC, 1.2-A current limit.
Power supply return connection, ground
Positive battery pack terminal
Negative battery pack terminal, BAT–, is common with DC–
No connection – R4 is set to 10 kΩ to bias the TS signal in a charging state (bq24081). See datasheet
(SLUS687) to activate TS for bq24081. Connector provides for optional external control.
Return for thermistor (when used)
Monitor JMP1-2 for STAT1, or apply a shunt across JMP1 for LED status.
Monitor JMP2-2 for STAT2, or apply a shunt across JMP2 for LED status.
No jumper => Termination Enabled. Place a shunt on JMP3 to disable termination.
(1) _{Factory jumper selections are shown in BOLD.}
2.2 Test Procedure
Setup the evaluation board as described above, by making the necessary I/O connections and jumper
selections. Prior to test and evaluation, it is important to verify that the maximum power dissipation on the
device is not exceeded: P_MAX = 1.5 W.
P_MAX = (V_(DC+) - V_(BAT+)) x I(CHG)
(1)
2
bq24081EVM 1-A Single-Chip Li-Ion and Li-Pol Charge
Management IC Evaluation Module
SLUU261 – September 2006
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