TPS61178: Compensation design per datasheet procedure

Steve Widener

Genius 11010 points

Part Number: TPS61178

Please provide clearer guidance on how to calculate Rc in the compensation section of the datasheet, Section 9.2.4.4.2

There is no clear equation to establish the value of Rc

over 8 years ago

0 EricLee over 8 years ago

TI__Guru 58351 points

TI engineer is working on this request. He will reply as soon as possible.

0 Jasper Li over 8 years ago

TI__Mastermind 46905 points

1. Let 's say setting the cross frequency fc = 10K
2. The gain of the power stage Kps can be calculated by equation 15.
3. the Rc = (Rdown+Rup)/(Kps*Gea*Rdown)

you can send me an email, i can provide you a calculation tool.

0 Roger Venable over 8 years ago in reply to Jasper Li

Prodigy 20 points

On the TPS61178 datasheet, Figure 23 shows a resistor for R(out) which doesn't exist as a physical component, but there isn't any discussion of it. "R OUT is the output load resistor", expected value in ohms, and low values seem appropriate. Where does this number come from? Equation 28 requires it, that's where I'm getting stuck.

0 Jasper Li over 8 years ago in reply to Roger Venable

TI__Mastermind 46905 points

Rout = VOUT/IOUT. VOUT (output voltage ), IOUT (maximum output current in the application)

0 Roger Venable over 8 years ago in reply to Jasper Li

Prodigy 20 points

Thanks, yeah... that was definitely giving me the best answers. I have a design with varying input voltage and system loads, the compensation calculations are a little trickier than I would prefer..

0 Jasper Li over 8 years ago in reply to Roger Venable

TI__Mastermind 46905 points

normally, you can design the compensation value at minimum input and maximum load.

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TPS61178: Compensation design per datasheet procedure