USB port connection getting lost

My USB port connection is getting lost to the Arduino mega 2560 when i supply external current through an LED driver upto 1000mamp. I tried checking for 250ma and 350ma 0n the serial monitor by powering dc motors at 12v dc...it works fine but only at 1A and above the connection b/w usb port and controller is lost.

Kindly need suggestions to the earliest.?

My USB port connection is getting lost to the Arduino mega 2560 when i supply external current through an LED driver upto 1000mamp

Most USB ports limit total current to around 500 milliamps! Then, over that cutoff threshold, the port cuts off power until the offending device is removed...

Time for a nice external power supply.