measuring floating inductor current in a truesine inverter application

[Jamie Morken]

LEM DCCTs. hall-effect devices. design an AC CT that wont saturate with
the DC current.

The LEM ones look pretty neat:
http://dkc3.digikey.com/PDF/T081/P2358.pdf

Good datasheets too, so with increasing frequency, it looks like the
gain of the sensor increases, so the output current is more than actual?

I guess that is why they have such fast step response to current spikes,
0.1uS in this datasheet:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=398-1024-5-ND

I thought I would have to use a current shunt and fast opamp for cycle
by cycle current limiting, but I guess these can be used solely for
this, in a 200kHz SMPS.

Are the Tamura parts:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=MT7320-ND

Suitable for cycle by cycle current limiting at 200kHz PWM frequency as
well?

cheers,
Jamie

 

[Terry Given]

The LEM ones look pretty neat:
http://dkc3.digikey.com/PDF/T081/P2358.pdf

Good datasheets too, so with increasing frequency, it looks like the
gain of the sensor increases, so the output current is more than actual?

I guess that is why they have such fast step response to current spikes,
0.1uS in this datasheet:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=398-1024-5-ND


I thought I would have to use a current shunt and fast opamp for cycle
by cycle current limiting, but I guess these can be used solely for
this, in a 200kHz SMPS.

Are the Tamura parts:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=MT7320-ND

Suitable for cycle by cycle current limiting at 200kHz PWM frequency as
well?

cheers,
Jamie

buried in the digieky text is the frequency spec, 50kHz (35kHz for
some), so I guess not. I'm using the LAH-25s for a couple of jobs at the
moment.

Cheers
Terry