Utracer6 waveforms

[Never Mind]

The utracer6 is a bit of a interesting beast.

Although based on the utarcer3+ design it has been extended so far that it has become quite a different unit in operation and software requirements.

Present GUI do not fully address these differences and limit it usefulness.

In my efforts  to understand uTracer6 errors I have collected a number of waveform photos that I thought to share with anyone interested.

One important difference between a uTracer6 and the uTracer3+ are the losses in the uTracer6 energy storage capacitors, the switch and other circuits in a uTracer6 can exceed 40 volts. 

Only a fraction of this loss is captured by the measurement system. 

The rest has to be very carefully estimated in the GUI software. 

Current GUI only partially address these losses.

The scope photos show.

Channel 1   Tube anode connection point

Channel 2   Energy storage capacitor voltage

Channel 3   Cathode connection point

[Never Mind]

Today parts came in and I started modding my Utracer6 for lower losses, lower droop and increased reliability.

I will detail all the changes needed to get there in the near future. 

Today is too nice outside to spend any more time indoors.

The short version for today.

Changed was ...

MOSFET is now a 0.46 ohm type from the stock 6.5 ohm MOSFET.

This reduces switch, fuse and wiring losses from 10.4V to 1.6V

MOSFET driver transistors were replaced with faster parts that have 6 times the collector current rating.

Several resistors have been added to control Dv/Dt and peak currents to limit ground bounce in the MOSFET control switch circuits.

C44 went from 1000uF to 4300uF to reduce cathode voltage bounce from 1.3V to 0.36V

C60,61 went from 50uF to 180uF to reduce energy storage droop from 29.6V to 7.6V.

All losses including energy storage capacitor droop is now reduced from about 45V to about 15V at a 1A measure current.

Seems a worthwhile reduction. 

The stock MOSFET was safe area rated for about 300V @ 1 amp for 1mS.

Reliability should be improved with a new MOSFET switch that is safe area rated for 1000V @ 2A for 1mS.

Review the new scope pictures to a stock unit above.