H Bridge Help for unusal application

[Marcwolf]

Hi Folks

I am planning to play around with some Murata Microblowers. If you have not heard of them they are tiny (and I do mean tiny) piezoelectric blowers. They work on a 15V PP Squarewave which swings between positive and negative at 25Khz. The current usage is very small but I may be runing several of them at the same time.

Looking at designing a circuit to drive them. One idea came to mind was using an H-Bridge chip and rapidly changing from forward to reverse at that speed. I can use a 08M2 as the oscilator (hey they are cheap enought)

The only concern I have is driving the H-Bridge chip at that speed.

Any suggestions?
Many thanks
Dave

 

[cdngunner]

25 kHz seems to be standard for a good bridge. Just Google it.

 

[SAborn]

Use a mosfet driver chip in replacement to the motor driver, cheaper and smaller, and faster.

 

[premelec]

If the current is really small you could do a 2 transistor 2 resistor bridge... or CMOS gates

 

[JoeFromOzarks]

Wow Dave! That's really cool! (Something for one of your costumes?) Let us know how you get it all worked out!

joe

 

[erco]

Or make a 30V PP DC squarewave oscillator and connect the microblower ground to +15V. Pity a 555 timer is not quite up to the task. 200 mA, but limited to 16V max.

 

[Dippy]

What is the current consumption?
I love the pun from Joe ; "really cool"

"the H-Bridge" : which H-bridge chip?
That will define speed and current, though I doubt if there will be any problems.

 

[techElder]

If it's a tiny "chip", and you are going to blow a lot of air (is this a government application?), then how many "chips" will be tied to this one driver? Each "chip" will add capacitance and have some effect on the driver capabilities and thus it's 'speed'.

EDIT:

I would look at circuits for driving ultrasonic rangefinder type piezos; especially stuff designed to work with the Polaroid piezo transducers.

EDIT2:

BTW, 1,900 Pa (Murata's stated pressure of the device) is about 1/4 PSI. More units = more pressure. At about 10 VPP, the static pressure is about 1/2 stated value.

LINK: http://www.murata.com/products/micromechatronics/feature/microblower/index.html

EDIT3:

I haven't been able to coax a datasheet out of Murata. A search of their site doesn't even bring results on the part number of the product - MZB1001T02. Mouser Electronics seems to sell it (backordered). About $20US.

EDIT4:

Murata forwarded a datasheet: View attachment MZB1001T02_SPEC_Ver3.0.pdf

ATTACHED: MZB1001T02_SPEC_Ver3.0.pdf

 

[Marcwolf]

Hi Folks
Thanks for the input
I have been doing some prelim experiments over the weekend. I have a 08m2 that I can get to put out 2 square waves at 25Khz. Each squarewave is the inverse of the other so when one is high the other is low. By feeding these into a L293 I should be able to approximate a high powered squarewave of 16V (with a 9v supply) moving between 8V above ground and 8 below ground.
The 9V can be supplied by a little Pololu Buck booster.

Joe - you are right. I am looking at micro cooling applications where the air source is away from where the air is needed. With the multiple units I am looking at making a belt of about 6 of the blowers to feed a cooling vest.

Take Care
Dave

 

[techElder]

Dave, you might want to check the datasheet on the L293. It's a rather older product and might have a bit of a problem switching past 5KHz. Trial-by-fire might tell you different, though.

... I have a 08m2 that I can get to put out 2 square waves at 25Khz. Each squarewave is the inverse of the other so when one is high the other is low. By feeding these into a L293 I should be able to approximate a high powered squarewave of 16V ...

Be sure to experiment with physically stacking the air pumps; making the output of one, the input of the other.