Problem with OPA547 parallel connection

Krishna Chaitanya2

Other Parts Discussed in Thread: OPA548, OPA547

Hi,

Is it possible to generate 1.3 A of current using three parallel combinations of OPA 547. I have used 3 OPA 547's in parallel i.e. load resistance (10 ohms) connected to three OPA 547 with a intermediate resistance of 10 ohms each.The power source i used was Aplab regulated DC power supply LQ 6324.

I have verified this case using TINA software it shows me driving current of 1.3 A.

over 13 years ago

0 Bruce Trump over 13 years ago

Guru 21975 points

Krishna,

Yes, it is possible to parallel several OPA547 power amps by using series resistors to promote current sharing. It is probably much easier, however, to use one OPA548.

Regards, Bruce.

0 Krishna Chaitanya2 over 13 years ago in reply to Bruce Trump

Prodigy 30 points

Hi Bruce,

I have a problem when I tried in this way. The current started flowing with at 3.5 V input only. Why is it happening so?

MY connection described below:

I have taken three OPA547 OPAMP's and connected in voltage follower configuration. The output pins of each OPAMP are connected with a 10ohm resistances. The other ends of these resistances are connected to a 10 ohm resistor (load).

Krishna.

0 Bruce Trump over 13 years ago in reply to Krishna Chaitanya2

Guru 21975 points

Krishna,

I believe that you may not have provided a negative power supply voltage on the V- terminals. What are the voltages on your power supply terminals? For an explanation, see this discussion:

http://e2e.ti.com/blogs_/b/thesignal/archive/2012/05/08/op-amp-voltage-ranges-input-and-output-clearing-some-confusion.aspx

Regards, Bruce.

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Problem with OPA547 parallel connection