Hello. I am trying to figure out how this Logic Level converter is working. I am trying to connect it like in the picture. Common ground, 5v to the HV pin and 3.3v to the LV pin. When measuring I have constant 3.3v out on L1 to L4. No matter what I put into H1 to H4. What am I missing? It says it…

[image] Dernebo: I'll just accept that this cheap amazon-LLC doesnt work the way I thought, or want... It does, picture for explanation. [image] Resistors in blue box go to the top row of pads. MOSFETs in blue box turn 90 degrees. Then all will resemble the amazon picture(and hopefully wo…

Right now I dont have any devices that are communicating. I just want to verify that I have understood it right, which I apparently haven't. :wink: I just want to see if I can via this cirquit convert a 3.3v signal to 5v or vice versa. I am mostly using Arduinos and Wemos D1 but at the end this mi…

The HV# pins are pulled-up to 5V and the LV# pins are pulled up to 3V. With nothing else connected to any of them (assuming proper power connection) you should see, measure, those respective voltages. When you take one side low (to GND), the corresponding "pin" on the other side should go low, too…

Yes there is clearly something wrong if thats how it is supposed to work. I verified again the status of all L-pins and H-pins. I looks like L1 to L4 is all High. (3.3v). Oh the H-side there is H1 and H2 that is constantly set to high (5V). H3 and H4 is Low (0v). I can not make any of the pins cha…

The only change of state that can be effected is by taking a "pin" to GND. (Feeding in 3V or 5V does not, cannot, change anything.)

They're each as you see here - [image]

See this application note for all the gory details. an97055.pdf 75.30 KB

As long as you have only connected 3.3V to LV-supply and 5V to HV-supply and you have nothing connected to the LV1 / HV1 Pins you will measure 3.3V / 5V because the 10K resistors R3 / R4 will pull-up to their voltage [image] If you really connect a device that is able to pull-down the voltage on…

Hi, @Dernebo Can you please post some images of your project? So we can see your component layout. Thanks.. Tom.. :smiley: :+1: :coffee: :australia:

https://cdn-shop.adafruit.com/datasheets/an97055.pdf Bottom of page 10 and top of page 11 explains how this circuit works. Inputs are needed to see how this circuit actions.

[image] Zardof: Bottom of page 10 and top of page 11 explains how this circuit works. Inputs are needed to see how this circuit actions. Very good explanation. This explanation stays on the functional level which is that level that is needed to understand the basic function of the circuit. I…

Logic Level Shifter problem

Other Hardware General Electronics

oldcurmudgeon June 16, 2023, 3:26pm 10

See this application note for all the gory details.

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Logic Level Shifter problem

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