Datasheet
Not Recommended for New Designs
bq24725
www.ti.com
SLUS702A –JULY 2010–REVISED NOVEMBER 2010
Setting Charger Options
By writing ChargeOption() command (0x12H or 0b00010010), bq24725 allows users to change several charger
options after POR (Power On Reset) as shown in Table 3.
Table 3. Charge Options Register (0x12H)
BIT BIT NAME DESCRIPTION
[15] ACOK Deglitch Time Adjust ACOK deglitch time.
Adjust
To change this option, VCC pin voltage must above UVLO and ACDET pin voltage must above 0.6V to
enable IC SMBus communication. After POR the bit default value is 0 and ACOK rising edge deglitch
time is 150ms. The long deglitch timer will only be enabled after ACFET turns on and turns off one time
this makes first time adapter plug in deglitch time always 150ms
0: ACOK rising edge deglitch time 150ms <default at POR>
1: ACOK rising edge deglitch time 1.3s
[14:13] WATCHDOG Timer Set maximum delay between consecutive SMBus Write charge voltage or charge current command. The
Adjust charge will be suspended if IC does not receive write charge voltage or write charge current command
within the watchdog time period and watchdog timer is enabled.
The charge will be 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>
[12:11] BAT Depletion This is used for LEARN function. During LEARN cycle, when IC detect battery voltage is below depletion
Comparator voltage threshold IC will turn off BATFET and turn on ACFET to power the system from AC adapter
Threshold Adjust instead of battery. The rising edge hysteresis is typical 305mV to 370mV.
00: Falling Threshold = 59.19% of voltage regulation limit (~2.486V/cell)
01: Falling Threshold = 62.65% of voltage regulation limit (~2.631V/cell)
10: Falling Threshold = 66.55% of voltage regulation limit (~2.795V/cell)
11: Falling Threshold = 70.97% of voltage regulation limit (~2.981V/cell) < default at POR>
[10] EMI Switching 0: Reduce PWM switching frequency by 18% <default at POR>
Frequency Adjust
1: Increase PWM switching frequency by 18%
[9] EMI Switching 0: Disable adjust PWM switching frequency <default at POR>
Frequency Enable
1: Enable adjust PWM switching frequency
[8:7] IFAULT_HI Short circuit protection high side MOSFET voltage drop comparator threshold.
Comparator
00: 300mV
Threshold Adjust
01: 500mV
10: 700mV <default at POR>
11: 900mV
[6] LEARN Enable Set this bit 1 start battery learn cycle. IC turns off ACFET and turns on BATFET to discharge battery
capacity. When battery voltage reaches threshold defined in bit [12;11], the BATFET is turned off and
ACFET is turned on to finish battery learn cycle. After finished learn cycle, this bit is automatically reset to
0. Set this bit 0 will stop battery learn cycle. IC turns off BATFET and turns on ACFET.
0: Disable LEARN Cycle <default at POR>
1: Enable LEARN Cycle
[5] IOUT Selection 0: IOUT is the 20x adapter current amplifier output <default at POR>
1: IOUT is the 20x charge current amplifier output
[4] Not In Use 0 at POR
[3] Not In Use 0 at POR
[2:1] ACOC Threshold 00: Disable ACOC
Adjust
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
[0] Charge Inhibit 0: Enable Charge <default at POR>
1: Inhibit Charge
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