Hi,

I have 30V low power supply (10-20mA) and I need to reverse it at 10 Hz using microcontroller operating at 2.7V.

I am wondering what will be the best way to do it?

I looked option of H-bridge using mosfet but I am not sure if circuit will work with so different voltage levels, because gate G/S voltage is ~20V.

 

If instead of + 12V you put +30V in that schematic, you can burn GS of the MOSFETs

 

Yes.
I never used before mosfet, But GS voltage would be to high.
Cant find any circuit on the net maybe PNP/NPN transistors would be better.

SInce it is not a large current maybe using OP-AMP is better but they constantly take ~5mA per channel.

 

This circuit works fine.
http://tahmidmc.blogspot.ca/2013/01/using-high-low-side-driver-ir2110-with.html
Or use the circuit in the Picmicro Mechatronics prototype board and also AN893.
Max.

 

I wanted to say about the MOSFET driver but I had doubts. IR2110 is one of the most popular.
MOSFET Q1 needs 12V above OUT voltage.
For example V + = 30V , V gate q1 = 42V.

This is done with the floating source.
C1 is charged through D1 when Q1 is OFF.

The C1 charge is the only one that supplies the gate voltage for Q1.

The circuit in the figure works very well at some frequency.
But will it be able to keep Q1 open for a long time?

3h=10 000s, if R3 does not exist and the leakage current of the gate would be 1nA
C=Q/U=I*t/U Would probably work.
I would do it with discrete components. And another voltage of 12V for the gate.

 

These are useful.
http://www.silabs.com/tools/Pages/bootstrap-calculator.aspx
http://www.micro-examples.com/public/microex-navig/doc/097-pwm-calculator.html
http://www.microchip.com/DevelopmentTools/ProductDetails.aspx?PartNO=dm163029
Max.

 

This circuit works fine.
http://tahmidmc.blogspot.ca/2013/01/using-high-low-side-driver-ir2110-with.html
Or use the circuit in the Picmicro Mechatronics prototype board and also AN893.
Max.

That is only half bridge drive.
It may work but it is to complicated, looking for a simple solution.

 

That is only half bridge drive.
It may work but it is to complicated, looking for a simple solution.

The last one is a full H bridge.
Max.

 

Here is the schematics of the Mechatronics board.

 

These are useful.
http://www.silabs.com/tools/Pages/bootstrap-calculator.aspx

I tried the first link. The frequency must be between 2500Hz and 1000 000Hz.
I would have been curious at 2Hz or at 0..02Hz.
From link that capacity increases with frequency decrease. But I stop here. Do not continue a parallel discussion.

It is possible that the assembly works in the test, and more time is used without changing the state to burn Q1.(maybe I am wrong)

 

Here is the schematics of the Mechatronics board.

It uses same Vdd :-(

I believe it would be easier with PNP and NPN transistors.

 

Also that is the stepper circuit, there is one for the DC motor also.
P.54
Two controllers on the board.
Max.