BQ24707 Datasheet, PDF (15/36 Pages) Texas Instruments – 1-4 Cell Li+ Battery SMBus Charge Controller With Independent Comparator and Advanced Circuit Protection

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bq24707
bq24707A
SLUSA78B – JULY 2010 – REVISED MARCH 2011
Setting Charger Options
By writing ChargeOption() command (0x12H or 0b00010010), the IC allows users to change several charger
options after POR (Power On Reset) as shown in Table 3.
Table 3. Charge Options Register (0x12H)
BIT
[15]
[14:13]
[12:11]
[10]
[9]
[8:7]
[6]
[5]
[4]
[3]
[2:1]
[0]
BIT NAME
DESCRIPTION
ACOK Deglitch Time
Adjust
Adjust ACOK deglitch time.
0: ACOK deglitch time 1.3s for bq24707, 1.2ms for bq24707A <default at POR>
1: ACOK deglitch time set to minimum (<50µs).
To change this option, VCC pin voltage must be above UVLO and ACDET pin voltage must be above
0.6V to enable IC SMBus communication and set this bit to 1 to disable the ACOK deglitch timer. After
POR the bit default value is 0 and ACOK deglitch time is 1.3s for bq24707 and 1.2ms for bq24707A.
WATCHDOG Timer
Adjust
Set maximum delay between consecutive SMBus Write charge voltage or charge current command. The
charge is suspended if the IC does not receive write charge voltage or write charge current command
within the watchdog time period and watchdog timer is enabled.
The charge is resumed after receive write charge voltage or write charge current command when
watchdog timer expires and charge suspends.
00: Disable Watchdog Timer
01: Enabled, 44 sec
10: Enabled, 88 sec
11: Enable Watchdog Timer (175s) <default at POR>
Not In Use
11 at POR
EMI Switching
Frequency Adjust
0: Reduce PWM switching frequency by 18% <default at POR>
1: Increase PWM switching frequency by 18%
EMI Switching
Frequency Enable
0: Disable adjust PWM switching frequency <default at POR>
1: Enable adjust PWM switching frequency
IFAULT_HI
Comparator
Threshold Adjust
Short circuit protection high side MOSFET voltage drop comparator threshold.
00: 300mV
01: 500mV
10: 700mV <default at POR>
11: 900mV
Not In Use
0 at POR
IOUT Selection
0: IOUT is the 20x adapter current amplifier output <default at POR>
1: IOUT is the 20x charge current amplifier output
Comparator
Threshold Adjust
0: 0.6V <default at POR>
1: 2.4V
Not In Use
0 at POR
ACOC Threshold
Adjust
00: Disable ACOC
01: 1.33X of input current regulation limit
10: 1.66X of input current regulation limit <default at POR>
11: 2.22X of input current regulation limit
Charge Inhibit
0: Enable Charge <default at POR>
1: Inhibit Charge
Setting the Charge Current
To set the charge current, write a 16-bit ChargeCurrent() command (0x14H or 0b00010100) using the data
format listed in Table 4. With a 10mΩ sense resistor, the IC provides a charge current range of 128mA to
8.128A, with 64mA step resolution. Sending ChargeCurrent() below 128mA or above 8.128A clears the register
and terminates charging. Upon POR, charge current is 0A. A 0.1µF capacitor between SRP and SRN for
differential mode filtering, 0.1µF capacitor between SRN and ground for common mode filtering, and an optional
0.1µF capacitor between SRP and ground for common mode filtering is recommended. Meanwhile, the
capacitance on SRP should not be higher than 0.1µF in order to properly sense the voltage across SRP and
SRN for cycle-by-cycle under-current and over-current detection.
The SRP and SRN pins are used to sense R_SR with a default value of 10mΩ. However, resistors of other values
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Product Folder Link(s): bq24707 bq24707A
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