Astable oscillator + H bridge in one IC?

[tinkrmind]

Hello everyone! I'm designing a piezo buzzer driver circuit. I want a GPIO pin to drive the piezo, to switch it on and off. The constraints of the design are to have minimal size and quiescent current. I'm think a good solution would be to use a 555 timer to generate a square wave, use a not gate to get the logically opposite signal, and feed these to an H bridge that drives the piezo. But this would require two large ICs(555 and H Bridge). Is there a chip that combines this functionality so it has two logically opposite signals?

I searched digikey for H -bridge oscillator, and similar terms but didn't find anything.



I know that this would be easily done with a small microcontroller, but I'd rather not have to code 500 microcontrollers!

Thanks in advance!

[magic]

I was recently thinking about similar problem and an idea I came up with but not tested yet is to use an integrated half bridge driver.
Those things have one input and two outputs. If the input is low, the "low" output is driven high and the "high" input is driven low. If the input is high, vice versa. This is intended to drive a pair of FETs implementing a half bridge, but connecting load directly between the two driver outputs makes it a full bridge. There will be "dead time" during transitions when both outputs are held low for a microsecond or so.

An RC network between the low output and input will ensure oscillation if the driver has input hysteresis. They usually do.

Then there is IR2151, a self-oscillating half bridge driver, designed for self-clocking. Not sure if there are alternatives for 5V, though. You can certainly get normal drivers rated for 5V operation and do the input hysteresis trick.

The "high" output has separate supply, called Vs and Vb in IR datasheets. This would go to GND and VCC.

[SiliconWizard]

You can drive many small piezo buzzers with digital outputs directly.

[jkran]

Old thread but I tested this (using IRS21531D) and wanted to share results.
I attached the schematic I used tieing ground to VS and Vcc to Vb. This worked to get the desired waveform with Vcc from 11V to 15V. It triggered the PDLC but not fully clear as the film needs closer to 18V+. Does anyone have advice on an IC that I can run at 24V DC?
@magic Thank you for the tip!

[Zero999]

Piezo buzzers don't require much driver. A Schmitt trigger logic IC will do. Here's an example with the 74HC14. If you want to use a higher voltage, change it for the HEF40106B. The spare gates, in the hex package, can be connected in parallel with those driving the piezo, to provide a little extra drive.