BQ2409x charging current

None of our linear chargers enumerate. The bq24050 800mA linear charger has D+/D- pins and will do primary detection.  The bq24392 might charger detection device might be an option.

The bq2409x family are rated for up to 1A maximum.  The IC's power dissipation when intially charging a deeply discharged battery could raise the IC junction temperature above the thermal regulation threshold.  If so, then the IC will scale back the charge current until the power dissipation drops as the battery chargers.  This is typically a very short time period. 

For example, the IC's package has a 1.9W rating at 25C but a battery discharged to 2.7V would cause the IC to initially dissipate (5VIn-2.7Vbat)*1A=2.3W.

So without the computer enumerating, and the battery charger IC plugged into the USB port on the computer, i can successfully get around 1A of charge current out of the BQ2409x family of chargers?  I know that the battery charger IC has three stages, Pre charge, CC, and CV.  I understand in order to achieve the 1A i will need to set ISET to what it needs to be as well as keep the ISET2 pin floating around .9V

Yes, if the ISET pin is set to allow 1A charging current and if the USB port is capable of providing 1A, the bq2409x will be able to provide 1-A once the battery voltage is high enough that the power dissipation drops below the maximum and the thermal regulation circuit stops reducing charge current.   Keep in mind the maximum power dissipation rating for the package gets lower as the ambient temperature increases.

Also, note that if the voltage seen at the IN pin drops down due to the supply not being able to provide the request current or from a the voltage drop by the connectors and/or traces from the source to the IN pin, then the current could be reduced from 1A by:

1.  the VINDPM circuit if V(IN) drops down to 4.3V or 4.4V

2.  the dropout voltage, VDO, when the battery is close to full charge  

Ok i think i got i figured out now.  But one more question.  The USB port cannot supply 1A of current without enumeration and deciding if the device is a USB 3.0 device or not.  Out of a USB port the max current is 500mA i thought. once the device is enumerated and the USB host determined whether or not it is a low, full, or high speed device.  But without a USB microcontroller the USB will not be able to enumerate.

The max power out of most ports is 500mA but when charging a battery, unless the port is a CDP or DCP it is considered an SDP and limited to 100mA.  The USB BC 1.2 specification lists these requirements. 

So i will only be able to achieve 100 mA of current out of the USB port unless i use a USB capable microcontroller and enumerate so the computer thinks it is a dedicated charge port?  I was trying to stay away from using a USB capable microcontroller to save on cost.  I thought that this family of IC's would allow me to achieve over 100 mA of current out of the USB port without the computer thinking it is a dedicated charge port (i.e computer enumerates and does its thing) by setting the resistors on the ISET and ISET2 pins.

To be compliant with the USB Battery Charging 1.2 spec and not enumerate, your current must be limited.