Electronics > Projects, Designs, and Technical Stuff
Level shifting
<< < (10/11) > >>
Benta:
I will not go into a nitty-gritty discussion on this. Your complementary circuits are excellent for audio, but CVBS is extremely sensitive to phase distortion.
The simple emitter followers work well in CVBS applications, there is probably a reason that professional video equipment use them.

My 10k resistor was ill chosen, but for a first design suggestion on a paper napkin not too bad. :)

Note my comment in brackets: "parasitics". The more transistors you throw at an application, the more problems you can expect.

Zero999:

--- Quote from: Benta on January 08, 2019, 09:06:30 pm ---I will not go into a nitty-gritty discussion on this. Your complementary circuits are excellent for audio, but CVBS is extremely sensitive to phase distortion.
The simple emitter followers work well in CVBS applications, there is probably a reason that professional video equipment use them.

My 10k resistor was ill chosen, but for a first design suggestion on a paper napkin not too bad. :)

Note my comment in brackets: "parasitics". The more transistors you throw at an application, the more problems you can expect.

--- End quote ---
I'm sure you know it's not as simple as more components, more parasitics, more phase shift and less bandwidth. Using that logic know might thing the push-pull circuit I posted will use more power, but it doesn't. Indeed it will use less power, than the single ended class A two transistor amplifier.

I suspect the main reason for choosing the two transistor circuit is simplicity and I wasn't seriously suggesting the complementary circuit for this application. In fact I wouldn't recommend the discrete complimentary circuit for any video application. I'd opt for a video amplifier IC or high speed op-amp instead.
syntax333:
I connected my load to circuit which worked fine there is no change in signal shape however as I showed my circuit schematics I connected 300ohm resistor as a PNP follower resistor.

Problem is that the load only draws approximately 10mA but I want it to be able to draw more current (100mA). If I lower the resistor value I get higher current but there is heating problem.

Is there a way to solve that problem with additional circuitry or do I need to use higher W resistors and heat-sink on transistor?
Benta:
Do you really need to deliver 100 mW video power, or do you need to deliver 100 mA DC current? I'm confused...
syntax333:
I need to deliver 100 mA DC current to my load.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod