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Hi i have written the following code to send CMD0 to an sd card using pic16F877A. currently there is no response from the card. I am just looking for help to be able to send at least one command to the card i'll manage the rest on my own. Can anyone please help thank you.
Hi FVM well i went back to my initial secondary driver scheme. Its a long story but i had dropped it after a fuse and mosfet blow up, after some exchanges here thinking the scheme was bad and went for the simple mosfet + turn off transistor. Anyway thats a thing of the past, here is the gate...
Actually i plainly connected it to the oscilloscope probe and its bad.I have gone through how it should be loaded before and after recitifer for desired I and so on but Lets get back to my waveform steps please, it smy major worry right now. Thanks
Hi Orson, the current signal is a simple 1 turn primary and approx 100 turns secondary that i harvested out of a pc SMPS. There is no rectification on the secondary and I am using it as a simple means of current monitoring in first place. I will load and rectify the current sense later on for...
We'll get to that point later on at least for now the waveforms feeding the mosfet need to be cleaned i don't see the point of doing this now when i have issues with my gate drive waveforms which need to be addressed in first place. Inductance in the gate ok it can add to the process of...
Hi i've tried to apply deadtime first before doing some tweaking.
1) Does the current waveform start to shape better?
2) for my own learning purposes is this peak in current related to the steps in my waveforms?
Thanks
Hi e-design thanks for the circuit i will consider it but do you think it will really solve my issue? I've tried dead time but its of no use, varying the dead time does reduce the signal duty but even at lowest duty that i could set, the step remained in the signal and occupied the signal space...
Hi FVM thats my exact target right now. I am trying to find a waveform restoration circuit to be added after the GDT secondary to solve the problem. I am also thinking of adding some more deadtime through the TL494 which could help as well. If anybody has a circuit for the gate drive after the...
Hi Fvm thanks for the reply. Ok If i consider your first option i.e. Orson's option i would be driving the primary with a push pull CMOS I will search on that. I have some CD4011 handy could that do the job????
Am also thinking is there is any tuning that could be done to the BD139/140 that...
Hi i've measure the waveforms. This is the GDT secondary unloaded:
And this is ic signal versus signal at GDT secondary:
There is no issue with the BD139/140 combination the signal is unaltered after passing through these transistors.
The issue i.e steps in the waveforms is with the GDT...
I will try to disconnect the gate measure the waveform and diconnect the speed turn off and measure the gate transformer secondary to try to sort out the problem and post the waveforms here
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