TIDM-1001: Source code for SR turn off optimizing

Roger Périat

Expert 2040 points

Part Number: TIDM-1001
Other Parts Discussed in Thread: UCD7138, CONTROLSUITE, UCD3138A

Hi all

We are using the TIDM-1001 eval board for evaluating our custom hardware setup. For this we started with the 283779D source code contained in controlSUITE. This works well and therefore we are going further. On the eval board the UCD7138 are mounted and the 4 DCT signals are routed to the 28379D (GPIO 11,13,14,20). Unfortunately those 4 pins are not used by the source code I have.

Is there source code around which does the functionality stated in the doc (bold highlighted part)?

The documentation TIDUCT9 states in section1.6.5 SR PWM Drivers:

"... Four of these drivers are used to drive the four SR switches. This approach brings a huge performance or cost benefit to the system as no other type of additional, and usually dissipative, current or voltage sensing is required to determine this accurate turnon instant for the SR switches. The SR turnoff instant is controlled by the C2000 MCU."

Thank you very much and best regards

Roger

over 5 years ago

0 Hrishi Nene over 5 years ago

TI__Genius 10820 points

Hi Roger,

The bold highlighted part actually describes the default behavior in the TIDM-1001 implementation. The 28379 controller sends PWM signals to the UCD7138 SR FET driver. The 7138 may delay the turn-on of the SR FETs by delaying the rising edge of these PWM signals at its input to make sure SR turns ON only when there is current flowing through it. The turn-OFF part of the SR FET is governed by the falling edge of the PWM signals at the 7138 input.

You are correct, the DCT signal part is not implemented in this implementation. Unfortunately, we do not have available software that implements this.

Hrishi

0 Roger Périat over 5 years ago in reply to Hrishi Nene

Expert 2040 points

Thank you Hrishi for your answer!

I saw the description of UCD3138A (slua737b ). In there it is described that UCD7138 and UCD3138A can work together to optimize turn on and turn off, that's why I thought that the mentioned 'turn off' done by C2000 should be the 'optimized turn off' done by UCD3138A...

It seems that what I need is an implementation for C2000 doing the functions of UCD3138A adjusting the turn off edge by reading the DCT signals. Can you confirm that slua737b is a good starting point or is there a even better application note / description ?
Thank you very much for sharing your knowledge!
Best regards,
Roger

0 Shamim Choudhury over 5 years ago in reply to Roger Périat

TI__Genius 10995 points

Yes, slua737b will be a good starting point for you. We are not aware of any other app note.

Shamim

0 Roger Périat over 5 years ago in reply to Shamim Choudhury

Expert 2040 points

Thank you very much for sharing your knowledge!
Best regards,
Roger

0 Roger Périat over 5 years ago in reply to Shamim Choudhury

Expert 2040 points

Thank you!

0 Shamim Choudhury over 5 years ago in reply to Roger Périat

TI__Genius 10995 points

Thanks you

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TIDM-1001: Source code for SR turn off optimizing