I'm using a current transformer (CS4200V-01L) to measure the current in a half-bridge. I'm facing an issue where the signal out of the current transformer is asymmetric, almost as if the current transformer is DC biased. This is the rectified signal, measured across R42:
Below is the relevant circuit extract. The signal is rectified, fed to the burden resistor (R42), low pass filtered and fed into a microcontroller in the range 0 to 3.3V.
How come the signal is asymmetric? I figured that the current transformer operated as a floating current source - my simulation seems to think it is too.
Obviously there's something else going on here. I thought the transformer may be saturated but the current doesn't look to be higher than 20A and the transformer has a maximum sensed current of 35A. Also it does the same thing at 10A, and I don't think that would explain this problem anyway.
Any input would be appreciated.