poniedziałek, 20 maja 2013

Short pulse generator, part 3.

Last week I have finally put together the pulse generator described earlier. IXDD604 driver seems to work in a satisfactory manner producing ~ 30 ns pulses. Unfortunately I didn't had time to make any photos of the working setup, so for now I can show you only a single pulse measured using 150 ohm load (a regular power resistor for now).

Sweet, isn't it? There are several issues still to be resolved like oscillations after the pulse (so called ringing) and difficulties obtaining such pulses for different amplitudes and loads. The problem, most probably, is in the pulse shaper not in the power driver so I should be able to pursue this in order to get this device working better than it is now.

czwartek, 9 maja 2013

Short pulse generator, part 2.

At last I have some time to write about recent progress in the matter of the short pulse generator. I have almost finished making the first prototype of this device. I had decided to use an integrated output stage. After some research I found IXDD604, and IC from IXYS that is dedicated as an MOSFET gate driver. Maximum voltage is 35 V and current a A, so it exceeds my needs in terms of power. 35 V peak amplitude must satisfy our needs at this moment, as this solution is very neat and I do not want to go into more complicated solutions as this should allow us to generate <30 ns pulses without any fuss.

The PCB is a single sided, as most of the elements are SMD. Only the driver is in THT as I was unable to obtain an SMD IXDD604 here. Such a design allowed us to make this PCB with thermotransfer and soon the prototype should be ready and soldered. I will post it as soon as I solder the prototype and run some tests.