Non-inverting level shifter LTSPICE

[sabu31]

Dear All,

I am trying to implement a non-inverting level shifter using transistor in LTSPICE. I used the configuration given in
https://electronics.stackexchange.c...stor-as-a-switch-without-inverting-the-signal.

However when i implement. I get the output signal value Vout) same as that of input. What could be the issue.

 

[dick_freebird]

The "active" phase is the emitter, low. Then you get a Vce(sat)
across the NPN and should see 5V-ish across the load R2.
With B and E at 3.3V device is off and output is high (5V).

 

[KlausST]

Hi,

The schematic is hard to read, because standard has GND down, and power supply up. So I need to make a handstand to see it correctly ;-)

From my understanding the circuit should correctly translate 3.3V to 5.0V.

Didn´t check your attached file.

Klaus

 

[BradtheRad]

Your circuit operates the NPN in common-base mode. By changing voltage at the emitter, it changes base-to-emitter voltage relationship, thus changing current level through base-emitter (and the degree to which the transistor turns On or Off).

Your signal must be low impedance, in the sense that it has to provide a path to ground when it is low. By doing that it pulls the collector leg (namely V_out) to zero V.

When your signal is high, it makes emitter voltage same as base voltage, and allows supply voltage (5V) to appear at V_out.

 

[crutschow]

I get the output signal value Vout) same as that of input.

It's the same phase, but different amplitude.
Sim below:

Note that the input has to sink the current from both resistors.