Electronics > Projects, Designs, and Technical Stuff
YABSa: Yet another bench Supply (version A)
Jebnor:
I've been working on my new bench supply. I've successfully created a positive supply which has <5mVpp Noise at 12V, over a current range from 0 to 1.2A.
I use no ICs. Thought anyone? Is there anything I'm missing?
BravoV:
Not an expert, just a thought, since that D6 1N4148 diode is series with the zener forming the voltage reference, that D6 tempco is about -2.1 mV per celcius, isn't that will affect the output stability ? cmiiw
Jebnor:
--- Quote from: BravoV on October 05, 2013, 06:28:44 am ---Not an expert, just a thought, since that D6 1N4148 diode is series with the zener forming the voltage reference, that D6 tempco is about -2.1 mV per celcius, isn't that will affect the output stability ? cmiiw
--- End quote ---
Oh, Probably... Everything else is temperature compensated, as far as I can tell, so why skimp on the most important part.
I have a bunch of the 1N4742a's around, I could select one and adjust the current source so that it is above 12V and then use RV1 to fine tune.
codeboy2k:
--- Quote from: Jebnor on October 05, 2013, 06:47:35 am ---
--- Quote from: BravoV on October 05, 2013, 06:28:44 am ---Not an expert, just a thought, since that D6 1N4148 diode is series with the zener forming the voltage reference, that D6 tempco is about -2.1 mV per celcius, isn't that will affect the output stability ? cmiiw
--- End quote ---
Oh, Probably... Everything else is temperature compensated, as far as I can tell, so why skimp on the most important part.
I have a bunch of the 1N4742a's around, I could select one and adjust the current source so that it is above 12V and then use RV1 to fine tune.
--- End quote ---
I thought it was obvious... the zener's reverse biased and thus it's tempco is approx +2mv/C... the diode D6 being forward biased is approx. -2mV/C... the two tempcos cancel each other out and this stabilizes the voltage ref over temperature.
BravoV:
Cool :-+ , thanks guys.
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