Some of this content “Universal Driver 2.1b” is originally created by Steve Ward (stevehv.4hv.org) and is re-posted with his permission.

Steve Wards work with phase lead compensated drivers is most likely based off the work that Finn Hammer did on his driver modifications called the “Prediktor” that was a DRSSTC driver with phase lead.

The content of the folder stevehv.4hv.org/stevehv/lead_comp/ did not contain much written information, except the quotes below here with some details on the circuit. The pictures are from Steve, but the descriptions of them is the interpretation of Mads Barnkob.

It is recommended to read the article on the Universal Driver 1.3b to understand how the driver works and the changes from 1.3b to 2.1b will not seem to radical afterwards.

26th October 2009

Steve Ward built and tested the universal driver 2 with phase lead on his “DRSSTC Magnifier – Mark I” Created 4/15/05: http://www.stevehv.4hv.org/DRSSTCmag1.htm

The first tests was done on an unknown IGBT, and not the magnifier system above. Green is primary circuit current and light blue is inverter output voltage. Yellow is presumably gate drive signal.

For the tests that are known to be done on a CM300 IGBT brick, on the magnifier system, the following collection of oscilloscope screenshots was available. Green is primary circuit current and yellow is inverter output voltage.

26th March 2011

R26 added in series with C33 because when it was only C33 the peak voltage of the positive feedback (hysteresis)
was outside the save range for the comparator inputs. R26 and C33 provide short positive feedback pulses which helps keep the comparator from self-oscillating.

R27 added across C5: There seemed to be some instability in start up, sometimes the TL3116 would start off with
output HI, sometimes output LOW. R27 restores proper bias to the comparator input by discharging the DC offset that may be left across C5. I picked 100k for R27, but perhaps values as low as 10K may be required, i would not suggest going lower than 10k.

Steve Ward, 26th March 2011

The files for the quoted text above is the old files called UD2_1 and is listed at the bottom of this article.

2nd September 2012

You need EAGLE by Cadsoft (google it) to look at the board and schematic. You can get a free version on the web.

This project was created before i knew the importance of linking a schematic and board file. These files are not linked, consequently errors do happen!

I changed some biasing resistors for the phase lead comparator, if you have referenced the older versions you might notice this.

Im not sure the parts list is 100% up to date, i had to make some mods to the design after i ordered everything.

C33 controls a “no switch” time after each output transition on the comparator. Originally i found C33 could be just 220pF, but recently using CM600DU-24NF modules with a loooong 1uS or so delay in switching, i found i had to boost C33 up to 2.2nF.
This provided a longer period where the comparator has high immunity to noise, and without this there was severe “glitching” where the IGBT switch noise caused the comparator to switch several times instead of once per half-cycle.

R11 R12 and C9 with IC4E form a pulse-width limiter that is frequency dependent. You can disable it by shorting out C9.

Steve Ward, 2nd September 2012

The files for the quoted text above is UD2_1revb files, which are the latest and those that you should use!

• 1 Universal Driver 2.1b Schematic (.pdf)
• 2 Universal Driver 2.1b Schematic (.sch)
• 3 Universal Driver 2.1b Board file (.brd)
• 4 Universal Driver 2.1b Parts List (.xls)

1st May 2013

This is pictures of a finished universal driver 2.1b as I made it for my own large Tesla coil called Kaizer DRSSTC 3. I use a MAX913 as the TL3116 substitute.

Freewheeling Universal Driver 2.1b

The /leadcomp/ folder also contained a folder called /UD freewheeling driver/ which contained schematic, PCB layout, Atmel microcontroller code and gerber files for a freewheeling driver add-on

• 1 Freewheel controller Schematic (.sch)
• 2 Freewheel controller Board file (.brd)
• 3 Freewheel controller Code (.c)
• 4 Freewheel controller Gerber file (.cmp)
• 5 Freewheel controller Gerber file (.dim)
• 6 Freewheel controller Gerber file (.drd)
• 7 Freewheel controller Gerber file (.ins)
• 1 Freewheel controller Gerber file (.sol)

Old files that should not be used, only listed for historical reference

• 1 Universal Driver 2.1 Schematic (.sch)
• 2 Universal Driver 2.1 Parts List (.xls)
• 3 Universal Driver 2.1 Components (.pdf)
• 4 old_DRSSTC_UD_2_1 (.pdf)
• 5 old_DRUD2parts (.xls)
• 6 old_UD2_1bottom (.pdf)
• 7 old_UD2_1compvals (.pdf)
• 8 old_UD2_1top (.pdf)
• 9 old_UD2_3schem (.pdf)