I am trying to connect a TPA2012 Audio Amplifier with Arduino and I don't know which ports should be connected to Arduino.
The Arduino is connected to a SD card adapter, an Ultrasonic sensor (HC-SRO4), and a 3W 4Ohm speaker. There is a .wav audio file in the SD card which is played on the speaker when an object is detected by the sensor. However, the volume at the speaker is very low and I want to connect the amplifier to increase the volume.
Please help me to increase the volume of the speaker by using either TPA2012 amplifier.
Description of Amplifier:
Stereo 2.1W Class D Audio Amplifier - TPA2012
Output Power: 2.1W at 4Ω, 10% THD, 1.4W at 8Ω, 10% THD, with 5V Supply
PSRR: 77 dB typ @ 217 Hz with 6 dB gain
Designed for use without an output filter, when wires are kept at under 2"-4" long
Four pin-selectable gains: 6dB, 12dB, 18dB and 24dB. Select with the onboard switches or by setting the G0 and G1 breakout pins
Click-and-pop suppression
Thermal shutdown protection
Independent channel shutdown
Low current draw: typ 6mA quiescent and 1.5uA in shutdown mode
If your samples are digital in the first place, why convert to analog to put through a class D amp which converts them back to digital? Furthermore there's a real risk of artifacts from the two sampling rates interfering.
Why not directly drive PWM signals to an H-bridge capable of driving the speaker?
However, the volume at the speaker is very low and I want to connect the amplifier to increase the volume.
Yeah... The "absolute maximum" current rating for the Arduino is 40mA, which from Ohm's Law means the minimum resistance is 125 Ohms. You should NOT directly-connect a 4-Ohm or 8-Ohm speaker! You can potentially fry your Arduino.
Put a series capacitor between the Arduino output and the amplifier input to remove the "bias". If the amplifier already has a series input capacitor, you don't need to add one, but if you don't know, another one won't hurt. 1uF will work (with the +side toward the Arduino).
You'll probably also want to add a volume-control pot at the input if there is not one already.
Use the minimum 6dB gain. You don't actually need any voltage gain.* You need current gain.
If your samples are digital in the first place, why convert to analog to put through a class D amp which converts them back to digital? Furthermore there's a real risk of artifacts from the two sampling rates interfering.
I agree with that! ...I wouldn't feed PWM into my regular (class A/B) hi-fi amplifier either!
When you directly-connect the speaker and overload the Arduino you are no longer getting 5V out.
Setting the PWM frequency to a high value (either by direct programming or one of the timer libraries),
such as 31.25kHz (16MHz / 512) or 62.5kHz (16MHz / 256), and then adding an RC output filter and
DC-blocking capacitor to the output pin, will provide a crude analog output.
An RC product of about 50us is a plausible compromise break point for the low pass filter, providing
attenuation of the PWM frequency without losing too much audio bandwidth.
Once you've an analog signal you can put it through any audio amp that takes analog in, but
the issue remains about possible interference between PWM frequency and the class-D oscillator,
which is a bit like pot-luck if you don't know both of these up-front.
Its probably OK, but sometimes you might experience a beat tone if the frequencies mix into the
audio band.