Datasheet
SLUU158 – April 2003
7
bq24020/bq24023 Charger (bqTINY-II) Evaluation Module
2.3 Alternative Test Procedure
The procedure in 2.3.1 describes a quick test to verify charging states without the need for a battery or
expensive test equipment.
2.3.1 Equipment
1. Power source: current limited 5-V lab supply with its current limit set to 1.0 A ±0.1 A
2. Two fluke 75, equivalent or better
3. Load test board as shown in Figure 1.
UDG–03044
R1
2 kΩ
0.25 W
DC+
USB
INPUT
BAT+
BAT–
+
–
USB
PLUG
DC–
BAT+
BAT–
DMM1
+
DMM2
S3 S1
S2
C1
1000 µF
R8
0.1 W
R9
680 Ω
0.25 W
R2
120 Ω
0.25 W
R3
120 Ω
0.25 W
R4
120 Ω
0.25 W
R5
10 Ω
2 W
R6
10 Ω
2 W
R7
2.4 Ω
2 W
Power Supply
5.1 ±0.1 V
I
LIM
1.0 ±0.1 A
From
0.5 A
Port
bq24020EVM
bq24023EVM
1
2
3
A
Settings for Switch S2
1. ON (Fast Charger for USB 0.5 A)
2. OFF
3. ON (Fast Charger for Adaptive Source)
A
NOTE: R5, R6 and R7 5% or better. All other resistors 1% or better.
Figure 1. bq24020EVM/ bq24023EVM Testing Setup
2.3.2 Equipment Setup
1. Connect the load board to the BAT+ and BAT–. Set switches SW1 and SW3 to closed and switch
SW2 to off (center).
2. Connect a voltage meter, DMM1, to the BAT+/BAT– output to monitor the output voltage (range is
0 V to 5 V).
3. Set the lab supply for 5.1 V ±0.1 VDC, 1.0 A ±0.1 A current limit and then turn off supply. Connect
DMM2 across R8 to monitor the current (R8 should be a 1% or better resistor if it is used for current
measurements).
4. Shunt jumpers should be installed on J6–DC+, J7–LED, J9–LED, J3–0.5, and J4–LED.
CAUTION:
If USB port is a low power port (0.1 A) and the charger is set up to draw 0.5 A, then problems or
damage to the USB circuitry may occur. Therefore, when powering from a 0.1-A port, one should
set J3 to 0.1 A and replace steps 7.8 through 7.11 with the following: Turn off J1 power source,
set jumper to J6–USB, SW2–off, and close switches SW1 and SW3. Plug in USB power source,
verify output voltage, BAT+, regulates between 2.5 and 2.9 V
DC
and both LEDs are lit. Open switch
SW1 and verify output voltage, VBAT+, regulates between 4.160 V
DC
and 4.240 V
DC
.