The max power of Configuration Descriptor is not work | Cypress Semiconductor
The max power of Configuration Descriptor is not work
we desinged a board( the cy3014 is be described composite device(UVC + CDC) )，the max power it need is more or less 600mA when it works,but the question is when i set the max power of Configuration Descriptor to 0x64(usb3.0 will be 800mA > 600mA). at the same time it just use the USB3.0 power to supply, in this case the composite can be enumerated in PC. but when i let it work,this composite device will be disappear;so i must use external power to supply this board,it can able to work normally.which means the max power i set in Configuration Descriptor is not work.
And when i configure the max power to 0x0c(usb3.0 will be 96mA).in this case,I let my board work using USB3.0 power supply and external supply, i find the electricity(external supply) is 0.36A and electricity(usb3.0 power supply) is 0.21A .this mean the total electricity is 0.57A,but the question is the value of electricity(usb3.0 power supply)--0.21A is much bigger than the max power(96mA) i configure, which all mean the max power i configuration in Configuration Descriptor is not work.
hope someone can help me to solve my doubt(usbDescriptor is attached).