Help me design selector circuit pls.

[kimera]

 Please help me design auto selector circuit from this condition
VccInput 9-80Vdc500mAMax
IF VccIn <=15Vdc to circuit A
IF VccIn >=20Vdc to circuit B

**lowcost

Thanks to everyone who commented

[BennoG]

what is the current draw of circuit A and B ?

[coromonadalix]

where here to help in any design, comment and improve if possible

but not do the job for you


no need for current draw sensing   just some basic voltage comparators  with set values  for higher than,    lower than ...

you have tons of working principles on the web

an example
https://forum.dronebotworkshop.com/help-wanted/easy-way-to-automatically-switch-circuits-on-and-off-when-a-certain-voltage-is-reached/



even with cheap mcu  like arduino    you can define more controls like : settings - thresholds - conditions    etc ...

https://microcontrollerslab.com/automatic-power-source-selector-circuit-arduino/   code not free tough

[Ian.M]

Other considerations are how fast the input can rise/fall, and what delay is acceptable - i.e. expecting it to switch instantaneously from A to B or visa versa is unrealistic.

Also the specification is ill-defined.  What happens in the range 15 V  < VccIn < 20 V?
Should both A and B be off, or should it retain its previous state or something else?

The near 10:1 supply voltage range (9 - 80 V dc) makes it difficult to get a regulated supply for the control circuit if more than a few mA is needed.  Are any other (possibly stabilised) supply rails available?

[kimera]

where here to help in any design, comment and improve if possible

but not do the job for you


no need for current draw sensing   just some basic voltage comparators  with set values  for higher than,    lower than ...

you have tons of working principles on the web

an example
https://forum.dronebotworkshop.com/help-wanted/easy-way-to-automatically-switch-circuits-on-and-off-when-a-certain-voltage-is-reached/



even with cheap mcu  like arduino    you can define more controls like : settings - thresholds - conditions    etc ...

https://microcontrollerslab.com/automatic-power-source-selector-circuit-arduino/   code not free tough

Thanks for the information, I will study more.

[kimera]

what is the current draw of circuit A and B ?

250mA max