MOSFETs pulsing at a frequency out-of-phase

[tim9000]

<Moderator's note: Spin-off from a related thread: https://www.physicsforums.com/threads/h-bridge-diodes-or-rather-the-lack-of.915992/>

I've always wondered: What do people usually use for gate drivers for mosfets and H-Bridges?
For example; say I wanted to have a couple MOSFETs pulsing at a frequency out-of-phase with each other, what would I use to drive the gates?
Cheers

 

[davenn]

For example; say I wanted to have a couple MOSFETs pulsing at a frequency out-of-phase with each other, what would I use to drive the gates?

A PIC microcontroller would be ideal

 

[tim9000]

A PIC microcontroller would be ideal

Ah, I was afraid of that, no easy way.
Are there chips you can get where you can set an approximate oscillation frequency with resistors, to pulse on and off, and use that chip to drive a MOSFET or H-bridge?
(That way I could just use a NOT gate to drive the opposite too?)

Thanks!

 

[Tom.G]

Are there chips you can get where you can set an approximate oscillation frequency with resistors, to pulse on and off, and use that chip to drive a MOSFET or H-bridge?

Google search for: 555 timer
over 800 000 hits for data sheets and circuits

 

[jim hardy]

Learn basics of PWM by starting with a TL494
http://www.ti.com/product/TL494
that family has devices of any complexity you want but I've only played with the 494

then tack behind it an H-bridge driver - any search turns up too many of them to comprehend.

 

[sophiecentaur]

Ah, I was afraid of that, no easy way.

Sympathy. Personally I would think of it in terms of hardware. If the phase relationship is to be fixed and a simple fraction of a cycle then I would use a clock oscillator or n times the final frequency where n is a convenient value so that you can have a divider / counter with two output clock signals which are an integral number of fastclock periods apart. The two output signals are then as firmly bolted together as gear wheels, driven by the same shaft.
The micro controller solution is a piece of cake if you already have experience of driving and programming the device. Could be time worth spending in learning but it would depend on when you may need to do something similar in the future.

 

[jim hardy]

http://www.intersil.com/content/dam/Intersil/documents/an94/an9404.pdf

http://www.nxp.com/documents/data_sheet/UBA2033.pdf

http://www.ti.com/lit/ds/symlink/drv8841.pdf

 

[Windadct]

There are more says to control the H bridge and other SMPS - than there are topologies.

As for the use of the Driver:

The Switch's( MOSFET or IGBT ) gate needs more power or current than the controller can provide.
The Switch's gate needs a different Voltage than the controller provides.
Most systems use N type devices for both top and bottom and thus needing to offset the Gate signal to the relative Voltage of the individual switch,
Provide isolation between the Controller ( sensitive) and the Power Electronics ( noisy)
The gate circuit needs to be tightly controlled for best performance ( Long leads and runs to from the controller to the Switch are problematic) - the noisy Power Electronics environment needs small local system to help prevent interference from the switching events.

there are others - TL-DR; POWER electronics and control electronics don't get along very well.