BQ24765_15 Datasheet, PDF (23/37 Pages) Texas Instruments – SMBus-Controlled Multi-Chemistry Battery Charger With Integrated Power MOSFETs

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BIT
10
11
12
13
14
15
bq24765
SLUS999 – NOVEMBER 2009
Table 5. Input Current Register (0x3F), Using 10mΩ Sense Resistor (continued)
BIT NAME
Charge Current, DACS 3
Charge Current, DACS 4
Charge Current, DACS 5
–
–
–
DESCRIPTION
0 = Adds 0mA of charger current
1 = Adds 2048mA of charger current.
0 = Adds 0mA of charger current
1 = Adds 4096mA of charger current, (Maximum charge current
8064mA.)
0 = Adds 0mA of charger current
1 = Adds 8192mA of charger current, 11004mA max)
Not used
Not used
Not used
ADAPTER DETECT AND POWER UP
An external resistor voltage divider attenuates the adapter voltage before it goes to ACIN. The adapter detect
threshold should typically be programmed to a value greater than the maximum battery voltage and lower than
the minimum allowed adapter voltage. The ACIN divider should be placed before the input power path selector in
order to sense the true adapter input voltage.
If DCINA is below 4V, the device is disabled.
If ACIN is below 0.6V but DCINA is above 4.5V, ACOK and VICM are disabled and pulled down to GND. The
total quiescent current is less than 10µA.
Once ACIN rises above 0.6V and DCINA is above 4.5V, VREF goes to 3.3V and all the bias circuits are enabled,
ACOK low indicated ACIN is still below 2.4V and the valid adaptor is not available. VICM becomes valid to
proportionally reflect the adapter current.
When ACIN keeps rising and passes 2.4V, a valid AC adapter is present. 100µs later, the following occurs:
• ACOK becomes high through external pull-up resistor to the VREF rail
• Charger turns on if all the conditions are satisfied (refer to ENABLE AND DISABLE CHARGING )
ENABLE AND DISABLE CHARGING
The following conditions must be valid before charging is enabled:
• Not in UVLO (DCINA > 4.5V, and VDDSMB >2.5V)
• Adapter is detected (ACIN > 2.4 V);
• Adapter – Battery voltage is higher than V(DCINA-VFB) Comparator threshold;
• SMBus ChargeVoltage(),ChargeCurrent(), and InputCurrent() DAC registers are inside the valid range.
• CE is HIGH;
• 2ms delay is complete after adapter detected and CE goes high;
• VDDP and VREF are valid;
• Not in Thermal Shutdown (TSHUT);
One of the following conditions will stop the on-going charging:
• SMBus ChargeVoltage(),ChargeCurrent(), or InputCurrent() DAC registers are outside the valid range.
• CE is LOW;
• Adapter is removed; (DCINA < 4V)
• VDDSMB supply is removed. (VDDSMB <2.35V)
• Adapter – Battery voltage is less than V(DCINA-VFB) Comparator threshold;
• Battery is over voltage;
• In Thermal Shutdown: TSHUT IC temperature threshold is above 155°C.
Copyright © 2009, Texas Instruments Incorporated
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