Hello everyone,
I'm posting here to get some feedback about my new alarm circuit:
I need only to output a fairly strong frequency, used as an audio indicator, nothing related to music.
The frequency is from few Hz to 5KHz, and needs to be heard let say when driving a bike.
The volume has to be ajustable (from CPU)
Average current drawn from battery must be less than 1mA as the application run with a coin cell battery.
Since piezo ceramic buzzer need from 10 to 30V, extra circuitery are requiered.
From here, they are 3 solutions:
The all in one, made for it:
http://www.ti.com/product/tpa2100p1
But consumes quite a lot (5mA)
The one with a choke coil
And the one I tried on breadboard:
A capacitor booster with diode, using a PWM at 100KHz and changing the duty to change the volume.
The consumption is less 1mA at full volume, and nothing when, no output as I can switch down the PWM (signal and booster)
The problem is the board space used with this solution.
So I wonder if any one can submit me a new design (like using push pull or so) to reduce the number of capacitor/diode while still being cheap.
Thanks,
I will keep you updated on my investigation.
I'm posting here to get some feedback about my new alarm circuit:
I need only to output a fairly strong frequency, used as an audio indicator, nothing related to music.
The frequency is from few Hz to 5KHz, and needs to be heard let say when driving a bike.
The volume has to be ajustable (from CPU)
Average current drawn from battery must be less than 1mA as the application run with a coin cell battery.
Since piezo ceramic buzzer need from 10 to 30V, extra circuitery are requiered.
From here, they are 3 solutions:
The all in one, made for it:
http://www.ti.com/product/tpa2100p1
But consumes quite a lot (5mA)
The one with a choke coil
An externally hosted image should be here but it was not working when we last tested it.
And the one I tried on breadboard:
An externally hosted image should be here but it was not working when we last tested it.
A capacitor booster with diode, using a PWM at 100KHz and changing the duty to change the volume.
The consumption is less 1mA at full volume, and nothing when, no output as I can switch down the PWM (signal and booster)
The problem is the board space used with this solution.
So I wonder if any one can submit me a new design (like using push pull or so) to reduce the number of capacitor/diode while still being cheap.
Thanks,
I will keep you updated on my investigation.