UCC28950: UCC28950

eli

Guru 13485 points

Part Number: UCC28950

SEE below question:

I work with project – 6kW charger.

To reduce high switching losses I build phase-shift converter with UCC28950 controller.

Input and output voltages are isolated with power transformer.

UCC28950 controller is installed in primary circuits to minimize MOSFETs switching time.

External output voltage regulator is installed in secondary circuits and is connected with

UCC28950 controller through optocoupler.

May I shunt UCC28950 error amplifier output (UCC28950 pin 4) with external switch or

signal from external regulator?

Or I have to use this error amplifier as proportional amplifier and to give to its input

signal from external regulator?

I have not used UCC28950 controller before.

Maybe you have good detailed user explanation for it?

over 8 years ago

0 Brian Johnson96 over 8 years ago

TI__Expert 3200 points

Eli,

I have routed this to an AE to help answer.

0 Colin Gillmor over 8 years ago in reply to Brian Johnson96

TI__Mastermind 25570 points

Hello Eli

This is a common enough application - putting the UCC28950 on the primary eliminates the need for an aux supply and gives you less delays in driving the MOSFETs. The reason for putting it on the secondary is to allow a faster control loop.

The best way to bring the error amplifier signal into the UCC28950 is to configure the on-chip as a unity gain buffer. Tie EA- to OUT and bring the signal from the opto-coupler into EA+ as I have sketched below. This allows the soft start routine in the UCC28950 to operate normally. this is the method I would strongly reccommend.

let me know if you have any further questions.

Regards
Colin

0 eli over 8 years ago in reply to Colin Gillmor

Guru 13485 points

Thanks,

Dont see your sketched !!

0 Colin Gillmor over 8 years ago in reply to eli

TI__Mastermind 25570 points

Hello Eli

Apologies for that and thanks for letting me know - here is the sketch again - do please let me know if it doesn't arrive -

If it doesn't arrive then send me an email at colingillmor@ti.com and I'll send it to you directly.

Regards

Colin

Power management

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UCC28950: UCC28950