Switching between -4.8V and -3.2V in Micro seconds

[MalikZain]

I need a fast switching circuit to switch between two negative voltage sources (-4.8V and -3.2V). I tried some circuits but not achieving the required result. I am new to this and don't hava a good practice with transistors and mosfets so that's why facing trouble. Can any body please provide me the way of achieving the solution, any circuit or any idea?

 

[rjenkinsgb]

What is the current requirement and what will the switch be driven by - eg. the control voltage levels?

If it's purely a voltage level, a simple analog multiplexer would do it, eg. a DG408 / DG409.
They have a rated operating delay of around 160nS

https://www.vishay.com/docs/70062/dg408.pdf

 

[Pommie]

How fast is fast? 1nS, 1uS etc.

Mike.

 

[MalikZain]

What is the current requirement and what will the switch be driven by - eg. the control voltage levels?

If it's purely a voltage level, a simple analog multiplexer would do it, eg. a DG408 / DG409.
They have a rated operating delay of around 160nS

https://www.vishay.com/docs/70062/dg408.pdf

Dear i need 200 to 300 mA output current and switching in 300 to 500 ns.

 

[MalikZain]

How fast is fast? 1nS, 1uS etc.

Mike.

Dear i need switching in 300 to 500 ns and 200 to 300 mA output current.

 

[crutschow]

What are the control signal characteristics, and what power supply voltages do you have available?

 

[MalikZain]

What are the control signal characteristics, and what power supply voltages do you have available?

Control signal is 0 to 5 volts. I have two voltage sources, one at - 4.8V and second at - 3.2V. I am getting these voltages from a DC DC regulator.

 

[crutschow]

Can you switch one off and then the other on with a short gap in-between, or does it have to switch directly between the two in <500ns?
If its that latter, then you have to add a small delay to insure one switch is off before the other turns on, to minimize any short-circuit current between the two supplies.

I have two voltage sources, one at - 4.8V and second at - 3.2V. I am getting these voltages from a DC DC regulator.

So where is the 5V coming from?

 

[crutschow]

What exactly is the purpose of switching these two negative voltages?