OPA328: Full wave rectifier, single supply, with adjustable level alarm.

Gerhard Kreuzer

Part Number: OPA328
Other Parts Discussed in Thread: OPA350,

Tool/software:

Hi,

just tried to design a current sensor monitor. I need to get an alarm, if the bidirectional current exeeds the allowed margin. Pulses were ok, rest could done in the FPGA.

To reduce the need of monitoring two levels I use a full wave rectifier. The level is trimmed manually. (Scientific instrument, no mass production).

Any suggestens to make this circuit better?

Is a TINA model for the OP328 available, because this could be the better choice than the OPA350?

Thanks for revieewing the circuit.

With beest regards

Gerhard

Sync Rectifier V3.TSC

over 1 year ago

0 Marek Lis over 1 year ago

TI__Guru 67601 points

H Gerhard,

Your circuit looks good. OPA328 model is available - I included it in the simulation below. I also added a compensation cap across the feedback resistor.

Sync Rectifier V3 (OPA328) - autosave 24-07-31 10_11.TSC

0 Gerhard Kreuzer over 1 year ago in reply to Marek Lis

Expert 2600 points

Hi Marek,

thanks a lot.

But you leave one OPA350 (the amp with the diode in the feedback). I want to reduce the amount of different parts and so I set this amp also to OPA328, but ... simulation hangs.

Where can I find the OPA 328 TINA model, or more general, where can I find other missing models? Looked at the product page, nothing to find.

With best regards

Gerhard

0 Marek Lis over 1 year ago in reply to Gerhard Kreuzer

TI__Guru 67601 points

Hi Gerhard,

The macro-models may be found under each product folder:

https://www.ti.com/product/OPA328?utm_source=google&utm_medium=cpc&utm_campaign=asc-null-null-GPN_EN-cpc-PP-google-wwe_cons&utm_content=OPA328&ds_k=OPA328&DCM=yes&gad_source=1&gclid=EAIaIQobChMI-cS6g_LRhwMV0RWtBh2wDAAhEAAYAiAAEgJZc_D_BwE&gclsrc=aw.ds#design-development

Yes, there is a convergence issue with one of the OPA328 - I reported the problem to our modeling team. Thus, in the meantime, please use the circuit as I sent it to you. After the issue is resolved, in the final schematic you will on use only OPA328.

0 Gerhard Kreuzer over 1 year ago in reply to Marek Lis

Expert 2600 points

.. oh my god. I looked there but lokked for TINA or SPICE, not for 'Reference design' ... sorry.

With beest regards

Gerhard

Thanks for helping.

0 Gerhard Kreuzer over 1 year ago in reply to Marek Lis

Expert 2600 points

Hi Marek,

I also need a symmetrical (DC free) output, they decide to use a pro audio recorder to record this signal. As I have the THS210 at hand, I used it.

To get things simpler I removed the negative bias circuitry, cause the OPA328 should be RR.

Now I get convergence problems again (told me D1). Any idea?

Is there something to simplify?

With best regards

Gerhard

Sync Rectifier V5.TSC

0 Marek Lis over 1 year ago in reply to Gerhard Kreuzer

TI__Guru 67601 points

Hi Gerhard,

Sometimes the default parameters need to be change to help simulator to converge. Please change the Shunt conductance from zero to 1p - see below.

By doing so the simulator found the convergence point and the transient simulation successfully completed - see below.

Amplifiers

Amplifiers forum

OPA328: Full wave rectifier, single supply, with adjustable level alarm.