The older ipv mods in the past (ipv3 IPv4 ipv5) ect have had references to acting/responding/firing with pulse with modulation but not having an official pmw board/chip set. Most often (if I remember correctly) regarding how it handles tc.
I believe Daniel from djlsb vapes uses this reference.
But I would not draw a comparssion line between an ipv to a pwm mod. I believe they are too different.