UCC28950: Error Amp

Kuramochi Tadahiko

Part Number: UCC28950
Other Parts Discussed in Thread: UCC28951, UC2844A

Hi,

Can we consider that the behavior of the error amp of UCC28950 is same as a general amplifier except for soft start input?

Best Regards,

Kuramochi

over 5 years ago

0 Colin Gillmor over 5 years ago

TI__Mastermind 25570 points

Hello Kuramochi-san

The short answer is '"yes"

The main characteristics of the error amplifier - input offsets and GBW product etc. are given in the datasheet.

BTW: I'd suggest that you consider using the UCC28951 instead of the UCC28950.

The UCC28951 device is an enhanced version of the UCC28950. It is a fully compatible drop-in replacement for the UCC28950. Refer to application note SLUA853 at http://www.ti.com/lit/an/slua853/slua853.pdf for more details. The UCC28951 is typically the better choice, especially for applications where the system may have to operate simultaneously at a duty cycle> 90% and current limit.

Regards

Colin

0 Kuramochi Tadahiko over 5 years ago in reply to Colin Gillmor

Guru 28715 points

Collin-san,

I have an additional question.

Is the output of error amp voltage output or current output?

We would like to know if the output is similar to UC2844A's one as below.

Best Regards,

Kuramochi

0 Colin Gillmor over 5 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 25570 points

Hello Kuramochi-san

The error amplifier in the UCC28950 has a voltage output like the UC2844A has although the current limits for the amplifiers may be different. The main point is that it is NOT a transconductance amplifier.

Regards

Colin

0 Kuramochi Tadahiko over 5 years ago in reply to Colin Gillmor

Guru 28715 points

Colin-san,

Thank you for your help.

> The main point is that it is NOT a transconductance amplifier.

Does it mean that the error amp of UCC28950 is voltage output, UCC2844A is current output?

Best Regards,

Kuramochi

0 Colin Gillmor over 5 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 25570 points

Hello Kuramochi-san

I may not have been clear. Neither of them is a transconductance amplifier and both of them have a voltage output.

Regards

Colin

0 Kuramochi Tadahiko over 5 years ago in reply to Colin Gillmor

Guru 28715 points

Hi Colin-can,

Thank you for your support.

I have an additional request.

Could you provide the equivalent schematic of the error amplifier output?

Best Regards,

Kuramochi

0 Colin Gillmor over 5 years ago in reply to Kuramochi Tadahiko

TI__Mastermind 25570 points

Hi Kuramochi-san

I don't have an equivalent schematic to hand but the op amp output is normal. It's linear operating range, output current and bandwidth are given in the data sheet. If you need more detail I can get it for you but it may take several days.

Regards
Colin

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UCC28950: Error Amp