Datasheet

bq24725A
SLUSAL0 –SEPTEMBER 2011 www.ti.com
Setting Charger Options
By writing ChargeOption() command (0x12H or 0b00010010), bq24725A 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
After POR, the first time the adapter plug in occurs, deglitch time is always 150ms no matter if this bit is
0 or 1. This bit only sets the next ACOK deglitch time after ACFET turns off at least one time. 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.
0: ACOK rising edge deglitch time 150ms
1: ACOK rising edge deglitch time 1.3s <default at POR>
[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 battery over discharge protection. During LEARN cycle, when the IC
Comparator detects battery voltage is below depletion voltage threshold, the IC turns off BATFET and turned on
Threshold Adjust ACFET to power the system from AC adapter instead of the battery. The rising edge hysteresis is
340mV. Set ChargeVoltage() register value to 0V will disable this function.
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] IFAULT_HI Short circuit protection high side MOSFET voltage drop comparator threshold.
Comparator
0: function is disabled
Threshold Adjust
1: 750mV <default at POR>
[7] IFAULT_LOW Short circuit protection low side MOSFET voltage drop comparator threshold.
Comparator
0: 135mV <default at POR>
Threshold Adjust
1: 230mV
[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] AC Adapter Indication 0: AC adapter is not present (ACDET < 2.4V) <default at POR>
(Read Only)
1: AC adapter is present (ACDET > 2.4V)
[3] Not in use 0 at POR
[2] Not in use 0 at POR
[1] ACOC Threshold 0: function is disabled
Adjust
1: 3.33x of input current regulation limit <default at POR>
[0] Charge Inhibit 0: Enable Charge <default at POR>
1: Inhibit Charge
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