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i.MX6 USB charger detector with a dead battery

Question asked by paulmerana on Jul 17, 2017
Latest reply on Jul 20, 2017 by paulmerana

Hello

 

We are looking to design an i.mx6 Solo or Dual Lite battery powered i.mx6 device which charges from USB which will meet the USB Battery Charging Specification. We currently have a charger which will interface with the i.mx6 charger detector USB_CHG_DET# line such that when this line is low there is a USB charger attached to the system rather than a SDP USB port. We were made aware of errata ERR006281 concerning the charger detector in the i.mx6 where as it requires VDDHIGH_IN to be powered up for the charger detector to operate. For our system to draw less than 100mA I can not turn on the PMIC / i.mx6. If we are plugged into a DCP we can boot right up however we must be able to detect that we are indeed plugged into a charger. If we are plugged into a SDP and if the battery has sufficient charge we can limit the input current to 100mA and power on the i.mx6 to allow it to enumerate and attempt to negotiate for a higher current limit. The problem is if the battery is dead or very low it can not do this.

 

1) VDDHIGH_IN is the input which feeds VDDHIGH_CAP. This power rail also powers NVCC_LVDS2P5, NVCC_RGMII, NVCC_MIPI. Are these rails safe to be powered up along with VBUS while no other i.mx6 rails are powered up?

2) What is NXPs solution for a USB/Battery powered device to pass dead battery provisioning? Is there a reference design?

3) What is NXPs recommended hook up scheme for VDDHIGH_IN to allow the system to detect the charger on power up without the rest of the i.mx6 from being powered on?

4) Currently in our system if the battery is not dead so vsys is already on and the USB is plugged in the system does not boot up without the ON/OFF button being pressed. Is there a way to make this automatic? (Power on USB VBUS detection)

 

Thank you

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