Greetings all,

I am developing a project - an Audio Spectrum display using IN-13 Nixie tubes to be driven from a Teensy 3.5.

So far I have tested with an Arduino which generates PWM @ 5V.

I have just realised that whilst the Teensy 3.5 is 5V tolerant, the PWM output signal is 3.3V

Based in the assumption that I absolutely positively need to generate a 5V PWM for maximum 'deflection' of my display I would like to know the simplest method of converting the PWM from 3.3V to 5V.

I have been reading about setting the outputs to 'Open Drain' and using a pullup resistor connected to 5V.

Is this a realistic approach? I plan to use all 20 PWM outputs on the Teensy to drive 20 display channels using the FFT functions to generate an audio spectrum display.

The circuit for the display uses a 1K / 1uf RC combination to approximate to an analogue voltage before being fed to an MJE340 transistor - this in turn controls the current through the IN-13 Nixie connected to a 150V supply.

The electronics that I am using is described here: http://www.smbaker.com/experimenting...ph-nixie-tubes

Could anyone share a working code example of what is needed to achieve this as well as suggested values for the pullup resistor?

Am I even taking the correct approach?

All pointers gleefully received.