I quick-glanced the HV5812 datasheet, and it's a push-pull driver, meaning that it drives-out approx 0 volts to turn the tube on, and 80V to turn the tube off. Even though the anode supply is significantly higher than the 80V rating of the HV5812 device, it's OK to do this because any leakage thru the nixie tube is clamped to around 80V by the ESD circuitry in the HV5812. As long as the tube's extinguishing voltage is greater than (Anode_supply_voltage - Driver_high_voltage), this clever driver trick will work nicely.
This is not the same situation with open-drain (aka open-collector) outputs, which have no clamps for positive voltage. Theoretically a tube could 'leak' a small current and drive the pin above it's rated limit. Not usually a problem for bipolar devices, but it will destroy a MOS device, which is why I dont recommend exceeding the datasheet parameters. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/defaf02e-4527-47b3-b371-012fe5a30649%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
