Conversion from positive pulse to negative pulse

[dk-001]

Hi,

For a low current power supply project I need positive and negative square pulses around 200 kHz frequency. Another requirement for the square wave is to have a variable amplitude between 0-10V. Some 555 timers can provide amplitudes close to Vin, so I can vary the Vin for 555 chip and get a variable amplitude. Could you please recommend a method to convert positive pulse to negative pulse (i.e. -10V to 0V) from these or maybe another method?

 I'm planning to use these as input to Cockcroft-Walton multiplier. If possible I would like to avoid using a transformer, and generate voltage (0V-100V or -100V - 0V) on the board by using 5V pr 9V DC input, without a need for negative power rail.

Thank you.

[greenpossum]

Another requirement for the square wave is to have a variable amplitude between 0-10V. Some 555 timers can provide amplitudes close to Vin, so I can vary the Vin for 555 chip and get a variable amplitude.

By Vin do you mean the supply voltage to the 555? You'll find that the 555 will not function below a certain supply voltage, certainly not 0.

[dk-001]

Yes, I meant Vin to 555.  I see you point. I don't need to go down to 0V as output if I cannot accomplish the requirements (i.e. I can live with a certain startup value).

[Jay_Diddy_B]

Hi,

You don't need a -10V pulse to get negative voltages from a Cockcroft-Walton multiplier.





As the voltage goes up, the current goes down. You will only be able to get a few mA at 100V.

Regards,
Jay_Diddy_B

[David Hess]

Like Jay_Diddy_B says, a Cockcroft-Walton multiplier can be AC coupled on its input so reversing the diodes will invert the output.