#garfield Logs

Jul 28 2024

08:23 AM rue_mohr: yes? no?
06:38 PM aandrew: it looks like it was a schematic error; Q6 is NPN but Q7 is PNP (BC857). it looks like Q6/Q7 emitters are tied together to the large mosfet gate with Q6 (NPN) collector to 15V and Q7 (PNP) collector to ground
06:38 PM aandrew: but yes, fast turn on, slower turn off
08:47 PM rue_mohr: your sure the NPN collector was grounded?
10:22 PM aandrew: it's not
10:22 PM rue_mohr: interesting
10:22 PM aandrew: Q6/Q7 emitters are connected together and push-pull the gates of 3x IRFP054N; the NPN collector to 15V, the PNP collector to ground
10:23 PM aandrew: which makes a lot more sense but I wonder how well those two play nice together with such a slow pullup
10:23 PM rue_mohr: but are the collectors also connected togethor?
10:23 PM aandrew: no
10:23 PM aandrew: NPN collector to 15V, PNP collector to ground
10:23 PM rue_mohr: well thats a totem pole driver
10:23 PM aandrew: yes
10:23 PM rue_mohr: so its just a normal gate driver
10:23 PM aandrew: which makes a lot more sense
10:24 PM rue_mohr: :]