One half desires 3.3V logic. One other desires 5V. What do you do? Over on the [Playduino] YouTube channel, there’s a current video working us via a not-so-recent concern: varied approaches to level-shifting.
Within the video, the precise voltage domains of three.3 volts and 5 volts are given, however you possibly can apply the identical rules to different voltage domains, resembling 1.8 volts, 2.5 volts, or practically any two ranges. Numerous approaches are mentioned relying on whether or not you’re interfacing 5 V to three.3 V or 3.3 V to five V.
The primary approach to convert 5 V into 3.3 V is to make use of a voltage divider, constructed from two resistors. This can be a balancing act: if the resistors are too small, the circuit wastes energy; if they’re too giant, they inhibit quick indicators.
The second method to changing 5 V into 3.3 V is to make use of a naked resistor of no less than 10K. This can be a controversial method, however it could work in your scenario. The trick is to depend on the voltage drop throughout the collection resistor to both drop sufficient voltage or restrict the present flowing via enter safety diodes, which is able to clamp the voltage but in addition burn out with an excessive amount of present movement.
The third method to changing 5 V into 3.3 V is to make use of chips from the 74AHC collection or 74LVC collection, resembling inverting or non-inverting buffers. These chips can do the extent shifting for you.
The best method for going within the different route is to easily join them instantly and hope you get fortunate! For sure, this method is fraught with peril.
The second method for changing 3.3 V into 5 V is to make your personal inverting or non-inverting buffer utilizing, on this case, an N-channel Enhancement-mode MOSFET. Use one MOSFET for an inverting buffer and two MOSFETs for a non-inverting buffer. Simply be sure you decide N-MOSFETs with 3.3 V or 5 V gate drive voltage VGS. Alternatively, you need to use a buffer from the 74HCT collection.
The video gives a myriad of approaches to degree shifting, however you continue to must resolve. Do you’ve got a favourite method that wasn’t listed? Have you ever had good or dangerous luck with any of the approaches? Tell us within the feedback! For more information on degree shifting, together with issues to be careful for, take a look at When Your Stage Shifter Is Too Good To Perform.
