Vboost using PWM (manual) NOT hysteretic

[Fast]

Has anyone firmware code for SD6 MC33816 PT2000 or PT2001, using manual or PWM control of Vboost DCDC generator as promised in; fact-sheet/PT2000A4FS.pdf ? Only guidance is it should be like injector code, but is only low side, and needs voltage as well as current control.

[Fast]

Hi Atika

I was running from 48V, not 12V.  Also using GaN FETs and 15uH 25mOhm inductor, Ton  7us, Toff = 4us. These are very much installation and load dependant, remember the recovery from injector switching.

[Atika]

Thank you for your responce!
Currently i am testing the code on PS simultor. the inductor is 10uH 120mOhm, I used Ton as 5us, and it was not working at all. Then increasing it to 10us (i guess 7us will work as well), DCDC is switching as expected.
Thanks!

[Fast]

I am good for now. Yes the attachment shows the "manual" method for Vboost generation where microcode turns LS7 on and off.

Shall we close? Any other questions?

[guoweisun]

HI Fast

 All of these parts software are list here:

guoweisun_0-1736732852841.png

PT2000 3/4/6 Cylinders Engine Evaluation Board | NXP Semiconductors

Hope this could help you!

BR

[Fast]

For PT2001 see my solution attached, please critique .

@guoweisun @RafaR 

[Atika]

Hi Fast, Thank you for your example. what is the pwm_ton and pwm_toff in your DRAM? I tried you code, I am wondering why Vboost never reach VBOOT_H (which is defined as 65V)in my case

[guoweisun]

Could you please introduce or explain your code detail here?

[Fast]

Sure the reason see "PT2001 why inhibit Vboost?"

So there is an inner loop doing the PWM, if Vboost is low, with a limit for the On time. Direct control of LS7, no async hardware used, that may be susceptible to noise. Usual switch off is when current is reached. Then a coast down Off time. When Vboost target reached  the outer loop rests, till Vboost is too low.

Note the is no Vboost inhibit, as not needed see referenced post.

Code use at own risk!

[guoweisun]

guoweisun_0-1737510763987.png

But we implement Vboost using both sync and async modes

I didn't understand what you said, and I didn't know if it was a function inside our chip or some other way

[Fast]

Hi guoweisun

Yes there is some built in hardware, for PT2001/MC33816 only LS7 has this feature that is called VFM variable frequency mode, or hysteretic current control , or async phase. For a reason I do not entirely understand, this mode has issues, either this mode is sensitive to disturbances in Vboost from current drained by a load, or the current control of load supplied from Vboost. Apparently not sensitive if reservoir capacitor is taken directly to ground, avoiding Vboosts current sense.  It maybe booth. The manual PWM mode coded has avoided that condition. Multiple names for same feature often makes these powerful solenoid controllers seem unnecessarily complex, but persist you will be rewarded. Sync phase is essentially Off that sounds much simpler to me.

Fast_0-1737539689581.png

[guoweisun]

Please directly send mail to [email protected] ,I always discussed with him for this topic.

[guoweisun]

Does your above description have any relationship with your said manual PWM?