Shift Register Drivers

I’ve been using the Texas Instruments TPIC6595 and TPIC6B595 shift register with high current low-side driver ICs for a while for various tasks, usually driving LED lights and displays.

Someone posted a picture of an old gridless Tung-Sol VFD tube on Facebook and I thought to myself, well…. these are neat, but if you wanted to connect them up to a modern microcontroller, you’d need tons of pins unless you can easily multiplex it. TPIC6B595 wouldn’t really help you here as you’d need to drive +30V or so to the anodes.

I remember trying to figure out if there was a nice convenient high-side equivalent to the TPIC6595 series when playing with flip-dot display panels, and came up with nothing. Well, now I searched it again and came up with the MIC5891 which is exactly that, and it’s good to 35 volts! It’d be perfect for driving the VFD anodes.

The Important Fun Note: Driving a display this way with latched drivers will allow you to achieve a completely flicker-free readout, which is VERY important if you want to have your display appear on screen in film/TV applications! ESE clock displays operate like this (though I seem to vaguely recall they use something like 7490’s behind a set of D latches).

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.