bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion
and Li-Polymer Charge Management IC EVM
This user’s guide describes the bq24072/3/4/5/9(T) and bq24230/2 (bqTINY-III™) evaluation module
(EVM). The EVM provides a convenient method for evaluating the performance of a charge management
and system power solution for portable applications using the bq24072/3/4/5/9(T) and bq24230/2 product
families. A completely designed and tested module is presented. The charger is designed to deliver up to
1.5 A of continuous current to the system or charger for one-cell Li-ion or Li-polymer applications (see the
data sheet for correct device) using a dc power supply. The charger is programmed from the factory to
deliver 0.9 A of charging current. This EVM was designed as a stand-alone evaluation module, but it also
can be interfaced with the system and host via the connectors and headers.
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM
1
Introduction
1Introduction
The bq2407x and bq2432x powers the system while independently charging the battery. This feature
reduces the charge and discharge cycles on the battery, allows for proper charge termination, and allows
the system to run with an absent or defective battery pack. This feature also allows for the system to
instantaneously turn on from an external power source even when using a deeply discharged battery
pack.
This charger has one input and can be programmed to be used with an adapter or USB port as the power
source for the system. In the USB configuration, the host can select from the two preset input maximum
rates of 100 mA and 500 mA. The charger dynamically adjusts the charge rate based on the system load
to stay within the 100-mA or 500-mA maximum limits. An external resistor, RSET1, sets the magnitude of
the charge current. If the charge current exceeds the available input current, the voltage on the OUT pin
drops to the DPPM threshold or the battery voltage, whichever is higher. The charging current is reduced
to what current is available (I
BAT
= IIN–I
OUT
).
The integrated circuit (IC) charges the battery in three phases: conditioning, constant current, and
constant voltage. Charge is terminated based on minimum current. A resistor-programmable charge timer
provides a backup safety for charge termination. The charge automatically re-starts if the battery voltage
falls below an internal threshold. Sleep mode is entered when the supply is removed (Vin drops to the
battery voltage).
2Considerations When Testing and Using bq24072/3/4/5/9(T) and bq24230/2 ICs
Consider the following noteworthy items while testing and using the bq2403x ICs.
The bq24072/3/4/5/9(T) series targets current above a nominal 500 mA (>350 mA) and the difference are
The bq24079(T) ICs are regulated to 4.1 V. The "T" version uses a voltage-based TS bias, which allows
more flexibility in setting the temperature range, whereas the bq24072/3/4/5 ICs use current-biased TS.
The bq24230/2 family is identical to the bq24073/4 ICs except that they are trimmed and their target
current values nominally are at 300 mA (<450 mA). This family is suited for headset designs. The pinout of
each IC is the same across both families except pin 15 (JMP2 on the EVM); the pin 15 function is listed in
Table 1 under the Optional Function column.
2
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM
The two potential sources to power the system (V
USB port). The IC is designed to power the system continuously. The battery, in most cases, is the last
line of backup. If the adapter/USB input is not available (or disabled), the battery connects to the system.
In thermal regulation condition (TJ= 125°C not a first-choice design mode of operation), the charge current
is reduced to the battery, and the system still gets its power from the input. The battery supplement is
available in thermal regulation if the V
OUT
falls to V
disconnected, but the internal battery FET connects the battery to V
3Performance Specification Summary
Table 2 summarizes the performance specifications of the EVM.
Table 2. Performance Specification Summary for bq24072/3/4/5/9(T) and bq24230/2 EVMs
SPECIFICATIONTEST CONDITIONSMIN TYPMAXUNITS
Input dc Voltage, V
Battery Charge Current, I
Power Dissipation, bq24072/3/4/5/9(T) and bq24230/2
IC, 1 Cell
(1)
The HPA073 (bq24072/3/4/5/9(T) and bq24230/2) thermal design is optimized (8+vias, 0.031-inch PCB, 2-oz. copper) to give
θ
~ 27°C/W.
JA
I(AC)
O(CHG)
3.1Performance Recommendations
This IC is a linear battery charger and also powers the system from the input via the linear regulator
output. The key here is that this is a linear device that is most efficient when the input voltage is not too far
above the battery voltage (Vin = 4.75 V to 5.5 V). Too low of input voltage (less than the OUT voltage plus
the dropout voltage) results in degraded performance. Excessive input voltage (>5.5 V) results in excess
power dissipation and reduced performance via thermal regulation. The IC is rated to 28 V, and will not be
damaged with Vin voltages less than this, but any Vin voltage over the overvoltage protection (OVP)
threshold disables the IC. Thus, the recommended operating range for maximum performance is between
4.75 V and 5.5 V, with a preference toward the lower values.
) are the input source and the battery (adapter or
OUT
. In thermal cutoff (~155°C), the input sources are
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM
3
Test Summary
4Test Summary
This section covers the setup and tests performed in evaluating the EVM.
4.1Equipment
•Power supply (+5.25 ±0.25 Vdc), current limit set to 2 A ±0.2 A
•Three Fluke 75 DMMs (equivalent or better)
•Oscilloscope, Model TDS220 (equivalent or better)
4.2Equipment and EVM Setup
•Preset P/S#1 to 5.25 V ±0.25 V, 2 A ±0.25-A current limit, turn off and connect to J1-IN/GND ( + to IN
and – to GND)
•Connect a 10-Ω, 10-W resistor to J2-OUT/VSS
•Connect a fully discharged (Vbat <2.8 V) Battery to J3-BAT+/VSS (+ to BAT+ and – to VSS).
•Apply the jumpers as per Table 3.
•For the bq2407xEVM, adjust the potentiometers as follows (measure resistance from TP# to VSS):
– R8 (ILIM-TP12) = 750 Ω (743 to 757); R11 (ISET-TP16) = 1 kΩ (0.98 kΩ to 1.02 kΩ) and R16 (TS-
TP1) = 7.5 kΩ (7.3 kΩ to 7.7 kΩ); and for ’74 (-003): R10 (ITERM-TP15) = 3 kΩ (2.98 kΩ to
3.02 kΩ).
•For the bq2423xEVM, adjust the potentiometers as follows (measure resistance from TP# to VSS):
– R8 (ILIM-TP12) = 750 Ω (743 to 757); R11 (ISET-TP16) = 2.96 kΩ (2.93 kΩ to 2.99 kΩ) and R16
(TS-TP1) = 7.5 kΩ (7.3 kΩ to 7.7 kΩ); and for ’74 (-006): R10 (ITERM-TP15) = 3 kΩ (2.98 kΩ to
1. Verify that the equipment and EVM is set up according to the preceding section.
2. Verify that V
3. Turn on P/S#1, +5.25-Vdc supply to the UUT.
4. Verify V
PGOOD (D2) are on. If V
charge mode. If the IC is in fast charge, skip step 7.
5. Verify DMM#3, I
6. Verify that V
bq24073/4 verify that V
to VINfor Vin < 5.6 V.
7. Allow the battery to charge until V
programmed constant current to the battery unless the input cannot source the required current.
8. Verify I
9. Verify V
10. Set JMP5 (EN1) to HI, and verify that the chip has been disabled, D1 (CHG) has turned off, and the
11. SET JMP4 (EN2) to VSS. Verify that the input current is less than 500 mA (USB 500-mA mode). If the
12. Set JMP5 (EN1) to VSS and verify USB 100-mA mode. The system load is more than the allowed 100
P/S#1 current has dropped to zero. The internal battery FET must be on, connecting the BAT pin to
the OUT pin. Verify that the voltage on the OUT pin is close to the battery voltage. See Figure 2 for
EN1/2 modes of operation.
input current is restricted due to USB mode, or if the adapter is current limiting, the OUT pin drops in
voltage and enters the DPM mode, if the system current is less than the restricted input current. This
IC must be in DPM mode with the system voltage at the DPM
mA on the input, so the OUT voltage drops to the battery voltage, and the battery FET is switched on
OUT
is between 2.4 Vdc and 3 Vdc, and the charger is in precharge state: LEDs CHG (D1) and
BAT
OUT
is ~88 mV or ~0.9 A (for a 1-kΩ resistor on ISET).
BAT
: bq24072 – ~200 mV above the battery voltage.
OUT
Figure 1. Test Diagram
is approximately equal to V
is above the low-voltage threshold (V
BAT
is ~9 mV or ~0.09 A
BAT
for bq24072 is ~200 mV above the battery voltage or a minimum of 3.4 Vdc. For
OUT
is ~4.4 Vdc. Verify that bq24075/9(T) is ~5.5 Vdc for VIN> 5.6 V and equal
BAT
BAT
~3 V), then the IC is in fast-
(LOWV)
is between 3.3 Vdc and 4 Vdc. The charger delivers the
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM
5
Vin
Vout
Vbat
Suspend
DPPMMode
BatterySupplementMode
NormalMode
ChipDisable
BAT Current-Vbat0.1 W
EN->VSSUSB100
EN2->HIUSB500
t-Time-1ms/div
Test Summary
and supplements the input current. Verify that Vout has dropped just below the battery voltage and the
battery is supplying Ibat, ~(Vout/10 Ω – 100 mA).
13. Set JMP4 (EN2) to HI to return to the ISET mode where the programmed current is ~0.9 A.
14. Set JMP3 to HI, and verify that the charging is disabled and that the CHG LED (D1) turns off. Verify
that the system is still powered by the input. See Figure 3.
15. Set JMP3 to VSS, and verify that charging continues and that D1 turn on.
16. Record the OUT voltage and battery charge current. Adjust R8 CCW until the input current starts to be
reduced (~2 turns). Note how the OUT voltage drops and the charge current is reduced as the input
current limit loops kicks in and limits the input current. Adjust R8 to its original position
17. On the bq24075 IC, set JMP2 HI, and verify that the BAT FET turns off and allows no charging or
discharging of the battery.
18. Adjust the R16 (TS-Pot) up or down until the TS threshold is reached. Verify that the charging current
is disabled. Return the TS resistance within the normal range and verify the continued charging
operation.
19. Allow the battery to continue to charge until the battery reaches voltage regulation, ~4.2 V ±40 mV for
bq24072/3/4/5/9(T) and 4.1 V ±4 mV for bq24079(T). Verify that the voltage is regulated as the current
tapers over the next one-to-two hours depending on the battery capacity. See Figure 4 for a charge
profile (time in plot is not proportional to actual charge time).
20. Verify that the current tapers to around 90 mA (9 mV on DMM#3) when termination occurs. Note on
the ’72 and ’73 ICs that termination can be disabled by setting the TD pin HI (JMP2). Also note that on
’74, the ITERM resistor (R10) can adjust the termination threshold.
21. Verify that the LED, D1, turns off and the current drops to zero.
22. Turn off P/S#1, and allow the system load to discharge the battery until a refresh charge is initiated.
Verify that the battery voltage dropped to ~4.1 V for bq24072/3/4/5 and to 4.0 V for bq24079(T) prior to
refresh.
23. Verify that the LED, D1, did not turn on for the refresh cycle.
This concludes the procedure for demonstrating the features of this power path charger. See the data
sheet for more detailed explanations and instructive waveforms.
www.ti.com
6
Figure 2. Modes of Operation Tested in Steps 11 Through 13
bq24072/3/4/5/9(T) and bq24230/2 1.5-A Single-Chip Li-Ion and Li-Polymer
Charge Management IC EVM