about UCD9222+UCD7242 configuration with usb adapter

Without load on the UCD7242 you would not see zero current because the current sensing canout resolve the negative portion of the current ripple through the inductor.

But it should only be reporting a small amount, much less than 10A+.

Can you attach the project file (.xml), with the Design section completed, and can you provide the value of the resistor you have attached to the UCD7242's IMON pin to ground?

6131.4_ctrl pin.xml

hello Brad,

now, after we adjust the configuration, now the current is reduced to about 6A. but the rail#1 is always changing, sometimes there is no output voltage on rail 1.

please help me check whether somewhere of the configuration file is wrong.

the resistor of the IMON to GND is 8.8M;

the connection of the rail 2 is same as the rail 1, but the results are diffirent.

and after configurate the chip, how to use the hardware to trigger the start instead of using the "always converting"

Is “control pin only” mean only the pin of the chip ENA1&ENA2 is used to control the initial? Does other else pin control it? 

thank you ,Brad

best regards

1.  The Project file schematic, used to generate configuration parameters, indicates that the resistor to ground between IMON output and CS input is 10K ohms and the IOUT_CAL_GAIN reflects this in the project file, 200mohms.  If the resistor is actually 8.8M then this is what is causing the CLF error reported in the GUI, CLF = Current Limit Flag relates to the FAST_OC_FAULT_LIMIT.

ok， thank you Brad.

as your guidance, we work out the problem after adjusting the Cs and Rcs. Now we got the correct  Vout and Iout.

thank you very much for your kindness and help.

Have a good day.^_^

best regards

hello, Brad

today, we changed a bead followed the UCD7242, and something wrong happened  to the voltage. The rail1 can't output the voltage. But the rail2 is OK.

the fault is "FLT". we confirm that the bead is good.The other circuit elements and the configuration file  are not changed never. what's the reason to cause this?

and how can I resolve it? By the way ,the rail#1 and the rail# 2 are connected as the same method. and their external circuit elements are also the same.

Thank you very much.

An FLT reported from the Fusion GUI is an indication that the driver experienced a issue which requires that the rail be shutdown.

For the UCD7242, an FLT can be triggered for one of following conditions:

1.  High side mosfet over current fault.

2.  The UCD7242 die temperature exceeds 170C, this should create an FLT response on both halves of the UCD7242.

I would check Rail#1 SW node to see if it might be shorted to ground.

I assume that the bead you are refering to is actually the power inductor/choke connected to the SW node.

hello,

thanks Brad.

The bead is actually the power inductor/choke connected to the SW node.

I checked the Rail#1 SW node and confirm it is not short to ground.

In this case, any other reasons will cause this fault?

You know,   the rail#1 is the same as the rail#2 in every aspect except the output.

now, I plan to change the chip to try it again.

Its possible that the inductor value you chose allows the peak current at start-up to exceed the high side current threshold of the UCD7242.

It may be that this value is marginal and works for one rail but not the other and/or the actual value of the inductor on the bad rail is to the low end of its tolerance or the wrong value.

HI, Brad,

     After we changed the chips (ucd9222&ucd7242) for the now ones,  the power of the dsp core is right now.

Thank you very much.