06-10-2014 02:24 PM
Hi, I've posted before about excessive quiescent current consumption on the VCCAUX line, specifically, it's drawing about 1.3 amps of current when powered on. The curious part was that VCCINT line draws about 0.3/0.4 amps in the same environment. The power on sequence is VCCINT -> VCCAUX -> VCCIO
The data sheet suggests that quiescent current consumption is about 3 amps for VCCINT, and 180mA for VCCAUX.
Is it possible that some VCCINT connections are not properly connected on the board, therefore causing under current on that line, and due to VCCINT not getting enough power, VCCAUX ramps up the current consumption in response?
06-10-2014 08:28 PM
1) Make sure you are measuring the correct Power input pin.
2) Make sure you are following the power supply ramp time as below.
3) Check if the board connections are fine. Check if the decoupling capacitances have been properly included on the power lines as suggested in the PCB user guide UG203 - Table 2-4 pg 15 - http://www.xilinx.com/support/documentation/user_guides/ug203.pdf
06-11-2014 12:12 AM