XS2410 current feedback issue

[sonerb]

Hello,

I use XS2410 smart HS driver for driving proportional valves. (max 2A)

I use in PI controller mode. I can set the current correctly.

However, FB_IOUTx register (that is current feedback on Ton/2) doesn't give correct values.

Output current is okay. (I can test via oscilloscope with current probe.)

FB_IOUTx register must be 10 bit (0 - 1023) but it can give bigger values than 10bit.

TEST-1

currentSetPoint[0] = 48 -> 48 * 12.5mA = 600mA

FB_IOUT1 = 650 -> (650 * 5000mA) / 1023 = 3176mA

PI_DC1 = 320 -> (320 * 100%) / 1023 = 31.28% 

TEST-2

currentSetPoint[0] = 120 -> 120* 12.5mA = 1500mA

FB_IOUT1 = 1550(?) -> (650 * 5000mA) / 1023 = 7575mA (?)

PI_DC1 = 810-> (810* 100%) / 1023 = 79.17% 

As you can see on TEST-2, FB_IOUT1 gives 1550. But this number bigger than 10bit.

I use NXP Q100 SW driver (Q100_eSwitch_SDK_SW) for test. (https://www.nxp.com/webapp/Download?colCode=Q100_eSwitch_SDK_SW&appType=license)

You can find my Q100 driver configuration at the attachment.

How can I read current feedback properly?

[RafaR]

I will start working on your case, I will contact you soon.

[sonerb]

Hello,
Is there any update on this topic?

[RafaR]

Hi sonerb

I apologize for the delay., I had some doubts so I consulted with other colleagues for a second opinion on the possibilities of the problem, allow me to share our points with you:

This problem could have 3 different reasons

1.- The input impedances are offset, the input impedances work with Quad 100 mΩ / Dual 50 mΩ depending on the configuration, these values ​​can be easily affected if there is no good precision with the impedances..

2.-  The configuration with the SPI could affect, maybe you activated the wrong configuration (Quad or Dual)

3.- The reference voltage has some variations, changing the reference voltage could affect the measurement.

Could you please send me your schematic and configuration?

[sonerb]

Hi RafaR,

I am using the driver in independent mode. I can set current point as 600mA and I can measure it correctly via oscilloscope. 

I can confirm that configuration is correct with readback registers.

I don't have any problem to drive load, I have a problem reading feedback from register.

All applied voltages are stable.

You can find the configuration at the attachment. (q100_driver_conf.txt)