Still triying to fix (CCS can go max. 10mA) first I checked trimmer and was OK also I checked the CCS following your instructions : I tied F+ & F0 together (the output connector's far left and right points). I looked for 1.5-2V VGS across each healthy DN2540 (outer pins) when the CCS is LV powered. VGS Q1 1.2VDC & Q2 0,0XVDC. Checked the related CCS diodes and are fine, removed the DN2540 & checked with Atlas Peak DCA75 & what surprie both DN2540 are OK?
Q2 VGS 0 in LV test is no good. Are you sure Q2 is good? Is there a dead Zener across Q2? Maybe there is oscillation in the CCS and sticks? See with the scope.
Yes Q2 VGS 0 in LV test is no good, I desoldered to change for a new one but before checked with Atlas DCA75 before to trash and measued as OK. Also I suspected like you about a dead Zener Diode: removed the two ans measured OK, I will look with the scope. Also desoldered & measured Q1 to calm my mind and measured OK.
I don't know what happened to R1: measures only 1R, now the CCS is OK, time to check the rest.
Only can reach with 123Vin = 118Vout, mine target 100V set SSHV2 CCS 50mA (30mA for the load & the rest for SSHV2)?
Have I to change something due to the fact the reg. is working in the low minimum output voltage?
Thanks. What's the hFE value of KSA1381, I ask because there are several grades: C,D,E & F? Or no matter?
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D class is about there, not too high HFE. Can be down to 75 sometimes even. I have some that low. HV transistors are not high HFE in general.
Congrats for fixing it and also getting it to work at 100V range.
Congrats for fixing it and also getting it to work at 100V range.
Sorry if this was asked previously in this thread; Wondering if it is possible to use the SSHV2 to produce 600V regulated power. Start with approx 700V raw. Potentially with the use of IXTP08N100D2 within the cascode and a different MOSFET than the IRF840?