Hi guys,
I have a high voltage source (~400v, generated from a disposable camera)
and i would like to use it to generate roughly 100us pulses into a purely resistive load (say once a second). (Assume i have enough capacitance next to the camera so drops are not a problem).
The thing is that i want these pulses to be bipolar, somewhat alike a motor which i want to spin in alternate directions.So naturally i started looking at h-bridge topologies.
I have 4 high voltage n-channels in my disposal so i thought - wouldn't it be neat if i could come up with an h-bridge running on 4 n-channels ? (23nm60nd)
I found this circuit with 4 n-channels:
http://www.hvlabs.com/Images/hbridgefund2.jpg
But the problem (as the author indeed mentions) is that the source of A1 is floating, so if i simply crank the gate to 5v, it wouldn't set the source to 5v, indeed when measured it is roughly 3v or so. The author suggests using a hbridge driver circuit, or i guess i could use a p-channel, but then - how do i avoid using the 400v switching signals i need to keep this h-bridge turned off (or even on, i cannot take it all the way to ground - only 20v or so below the source voltage)
My question is :
What would be a quick and dirty way for me to implement this dual polarity switching capability. Please note that i am switching the voltage basically into a resistor, so the inductive considerations relevant to motors shouldn't pose constraint in my case.
Thanks for all advice !
Lenny
I have a high voltage source (~400v, generated from a disposable camera)
and i would like to use it to generate roughly 100us pulses into a purely resistive load (say once a second). (Assume i have enough capacitance next to the camera so drops are not a problem).
The thing is that i want these pulses to be bipolar, somewhat alike a motor which i want to spin in alternate directions.So naturally i started looking at h-bridge topologies.
I have 4 high voltage n-channels in my disposal so i thought - wouldn't it be neat if i could come up with an h-bridge running on 4 n-channels ? (23nm60nd)
I found this circuit with 4 n-channels:
http://www.hvlabs.com/Images/hbridgefund2.jpg
But the problem (as the author indeed mentions) is that the source of A1 is floating, so if i simply crank the gate to 5v, it wouldn't set the source to 5v, indeed when measured it is roughly 3v or so. The author suggests using a hbridge driver circuit, or i guess i could use a p-channel, but then - how do i avoid using the 400v switching signals i need to keep this h-bridge turned off (or even on, i cannot take it all the way to ground - only 20v or so below the source voltage)
My question is :
What would be a quick and dirty way for me to implement this dual polarity switching capability. Please note that i am switching the voltage basically into a resistor, so the inductive considerations relevant to motors shouldn't pose constraint in my case.
Thanks for all advice !
Lenny