MPQ8632GVE-20 design with MPS DC/DC designer

Simulation Tools and GUIs
1

Hi MPS team,
I am designing 12V to 5V/10A + DC/DC circuit with MPQ8632GVE-20 by MPS DC/DC designer tool.
Some issues here:

  1. What is the difference between RAMP1 and RAMP2 in compensation type selection box?
  2. I am not sure my procedure of generating the R,C values. I just do as following: Input “input voltage”,“output voltage” , “output current” and "switching freq"to MPS DC/DC designer tool. manually select Lout in the database, for example 1uH/20A. Simply change CIN and Ccera to the value such as 2x10uF and 2x100uF. Then I click “Create Design” bottom, the tool generate Rslope and Cslope and R9, Rfb1 and Rfb2 as well. Is it the correct way of developing MPQ8632GVE?

I just change the Rslope to 100k which is more common and do “Create Design” again, Cslope, Rfb1 and Rfb2 are changed, can use them also?

2

Hi rg_gb,

Thank you for contacting MPS. To answer your questions:

  1. RAMP1 refers to a compensation network using a resistor. RAMP2 refers to a compensation network using a capacitor after the Rslope and Cslope instead. The choice is yours for which you’d prefer to choose. In reality, you would be able to put either a cap or resistor using the same package.

  2. Yes your procedure for creating the design is correct, the component values are chosen off of the values for Vin, Vout, Iout, Fsw, etc. Your values from DCDC designer will likely work, but my suggestion is to actually use the datasheet for values. There are equations in the datasheet that will absolutely work and I suggest using those instead. If you do not want to spend the time number crunching, please reach out to me at mpsnow@monolithicpower.com and I can send you a spreadsheet instead based on the datasheet equations. That said, you can use the DCDC designer values but it is easier to guarantee the values based on the datasheet equations.

Thanks,
Brendan Schoemehl
Field Applications Engineer
Monolithic Power Systems | MPS Now