Electronics > Projects, Designs, and Technical Stuff
Control JFET using MCU
Kleinstein:
The BSS139 or NSVJ3910SB3 look both OK. There is no explicit spec for R_on, but a curve for I vs V_DS that suggests some 10-20 Ohms as a typical value.
It would still need a negative control or supply, e.g. through the charge pump circuit shown by Zero999.
gaminn:
OK, I think I will implement BSS139 and the charge pump circuit mentioned above.
Zero999:
The NSVJ3910SB3 has an on resistance of 30R or better, when ID <10mA, but the BSS139 is cheaper and has a lower on resistance, so go with that.
--- Quote from: janoc on August 20, 2019, 10:17:25 am ---
--- Quote from: gaminn on August 20, 2019, 08:53:05 am ---When there is no power I want the switch to be ON. That is why I want to use JFET.
--- End quote ---
That sounds like you want a depletion-mode MOSFET and not JFET
--- End quote ---
It just needs to be a depletion mode device, be it a MOSFET or JFET.
janoc:
--- Quote from: Zero999 on August 20, 2019, 12:56:26 pm ---It just needs to be a depletion mode device, be it a MOSFET or JFET.
--- End quote ---
Given that it is for a switching application, the MOSFET is likely a more logical choice.
Zero999:
--- Quote from: janoc on August 20, 2019, 06:44:09 pm ---
--- Quote from: Zero999 on August 20, 2019, 12:56:26 pm ---It just needs to be a depletion mode device, be it a MOSFET or JFET.
--- End quote ---
Given that it is for a switching application, the MOSFET is likely a more logical choice.
--- End quote ---
Why?
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