very very urgent help needed regarding 0-5v pulse conversion to 0-12v pulse

[param_vlsi]

Hi,
I want a circuit which perfoms 0-5v pulse into 0-12v pulse.Can I do it an opamp 741.if any body know the corcuit help.I need it very urgent.



With regards,

Param

 

[dknguyen]

So you need an amplifier that has a gain of 12/5 = 2.4? Yes, you can do it with an op-amp. Just Google op-amp amplifier.

If your pulse is too high frequency then the 741 may be too slow an op-amp for you to use.

 

[param_vlsi]

actually I have PMOS with 12v supply.gate input is driven with microcontroller which will give digital high output of 5v.inorder to make PMOS off when 5v comes from microcontroller,I have to make 5v to 12v conversion at the gate of pmos.do u know any method that will do it in optimised manner.

 

[dknguyen]

THat will not work since the MCU pin voltage is referenced to ground, and the PMOS gate-source voltage is referenced to the MOSFET source (which is 12V). So the MCU pin will not properly control the PMOS if it is directly connected (it will never be able to turn the PMOS off). Also, even if you could directly connect the MCU pin to the PMOS gate, it would invert the logic output (MCU LO produces HI signal, and MCU HI signal produces LO signal). This is because a PMOS turns on when the gate voltage falls below the source pin voltage by a large enough amount (the opposite of NMOS).

You would need a pull-up resistor and a pull-down NMOS to drive the gate of the PMOS, and the MCU drives the NMOS. This will also correct the logic inversion.

 

[shingadaddy]

5 volt to 12 volt ( or a variety of output voltage levels) are commonly done with open collector buffers. Inverting and non inverting. dknguyen covers your other possible circuit oddity.

 

[Ubergeek63]

tying a base to 5V and driving the emitter resistor with a floating collector yields a current source that allows a gate resistor to ride a HV rail with the resultant gate voltage being determined by the gate resistor value.

 

[sg_karthick]

use a l293 bridge driver ic

 

[Speakerguy]

You can use a pull up resistor on the PMOS gate and toggle the MCU pin between output low and high impedance input my modifying the TRIS register (assuming you are using a PIC), essentially using it as an 'open collector' type output.

 

[Speakerguy]

Nevermind my above message, that will not work. Input voltage on the pin would go above Vdd and that isn't allowed. You need an actual open collector output if the V+ is going to be higher than Vdd.

 

[Triode]

There may be no point in saying this since its always one posters, But you can leave off the "very very urgent" and you'll get help just as fast.

 

[TiagoSilva]

I was watching this thread and i thought why havent they suggested the MAX232 yet ?

Ok i know it was designed for converting TTL Signals to/from RS232, but since RS232 works in the 12V level, this is what he is looking for... Or not...

 

[Leftyretro]

I was watching this thread and i thought why havent they suggested the MAX232 yet ?

Ok i know it was designed for converting TTL Signals to/from RS232, but since RS232 works in the 12V level, this is what he is looking for... Or not...

Depends on how precise he needs, my Max232 outputs +/- 10vdc when powered with +5vdc, and he would have to deal with how to clamp the negitive voltage to maintain a 0vdc low state.




Lefty

 

[mugdha293]

5v t0 12v conversion

Use ic l293d