Powertrain and Electrification Analog Drivers中的主题 Vboost using PWM (manual) NOT hysteretic

Vboost using PWM (manual) NOT hysteretic

Fast — Fri, 10 Jan 2025 15:07:40 GMT

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.

Re: Vboost using PWM (manual) NOT hysteretic

guoweisun — Mon, 13 Jan 2025 01:47:58 GMT

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!

Re: Vboost using PWM (manual) NOT hysteretic

Fast — Tue, 14 Jan 2025 13:46:08 GMT

For PT2001 see my solution attached, please critique .

@guoweisun @RafaR

Re: Vboost using PWM (manual) NOT hysteretic

guoweisun — Wed, 15 Jan 2025 01:06:53 GMT

Could you please introduce or explain your code detail here?

Re: Vboost using PWM (manual) NOT hysteretic

Fast — Wed, 15 Jan 2025 09:58:22 GMT

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!

Re: Vboost using PWM (manual) NOT hysteretic

guoweisun — Wed, 22 Jan 2025 01:53:42 GMT

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

Re: Vboost using PWM (manual) NOT hysteretic

Fast — Wed, 22 Jan 2025 09:56:28 GMT

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

Re: Vboost using PWM (manual) NOT hysteretic

guoweisun — Thu, 23 Jan 2025 02:09:40 GMT

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

Re: Vboost using PWM (manual) NOT hysteretic

guoweisun — Thu, 23 Jan 2025 02:19:28 GMT

Please directly send mail to lex.liu@nxp.com ,I always discussed with him for this topic.

Re: Vboost using PWM (manual) NOT hysteretic

Fast — Thu, 23 Jan 2025 09:55:48 GMT

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?

Re: Vboost using PWM (manual) NOT hysteretic

Atika — Fri, 21 Aug 2026 09:53:50 GMT

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

Re: Vboost using PWM (manual) NOT hysteretic

Fast — Mon, 24 Aug 2026 12:47:44 GMT

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.

Re: Vboost using PWM (manual) NOT hysteretic

Atika — Mon, 24 Aug 2026 14:07:46 GMT

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!