TL494: P vs PI controller in voltage feedback loop

Shyama Agrawal

Part Number: TL494

Hello,

The voltage feedback loop suggested in the datasheet doesn't include an integrator. Is there a specific reason why we should use only gain controller for TL494 or is it okay to use a PI compensator for the voltage loop. Is Rt mentioned in the text is referring to R7 in the image? Also, wouldn't the gain be reduced lower than 101 as the thevenin resistance of R3 and R4 will come in series with R5?

over 6 years ago

0 Teng Feng over 6 years ago

TI__Genius 13660 points

Hi Shyama,

Sorry for delay response, I will answer this question shortly.

Regards,
Teng

0 Teng Feng over 6 years ago in reply to Teng Feng

TI__Genius 13660 points

Hi Shyama,

From the TL494 Block Diagram, the error amplifier directly compares a sample of the output voltage to the reference, then used to adjusts the PWM to maintain a constant output current. So there is only a gain control without integrator control since the error amplifier is inside TL494.
Yes Rt is refer to R7 in figure11, the gain of error amplifier in the a constant 101, which can be calculated by:
Vin - (VREF/2 - Vin)/R5*R7 = Vout
here Vin=Vo/2
so Gain= Vout/Vin=101

Regards,
Teng

0 Teng Feng over 6 years ago in reply to Teng Feng

TI__Genius 13660 points

For the voltage feedback loop design, you can refer attached file, thanks. -----Teng

0333.slva666.pdf

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TL494: P vs PI controller in voltage feedback loop