Hello, I need to limit the input signal voltage in my TPA313 amplifier within the range of 0V to 5V, and since the input has an offset of 2.5V, a 4.7V zener is perfect for cutting off signal peaks almost symmetrically beyond ~5V and ~-0.7V. In practice, it works, but the TPA seems to enter some kind of loop every 2 seconds: with no signal applied, it works correctly for 1s, the next second there is a snap, where the speaker membrane remains tense and still at its maximum height without any sound, including noise.
Where am I going wrong? Or alternatively to a zener, what could I use for the same purpose?
The zener is placed with the cathode to RIN+ and anode to GND. There is a 100R resistor between the input cap and the preamplifier.
Grazie.
Where am I going wrong? Or alternatively to a zener, what could I use for the same purpose?
The zener is placed with the cathode to RIN+ and anode to GND. There is a 100R resistor between the input cap and the preamplifier.
Grazie.
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What about the power supply for the op amp?
Is it 9V single supply
Are you also driving the negative amplifier input?
Is it 9V single supply
Are you also driving the negative amplifier input?
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The power supply is 12V and the signal voltage offset is 6V in the preamplifier, then 2.5V after the capacitor. But the problem also occurs without any signal applied.
Ok, then also post the amplifier schematic.
Maybe you are upsetting the DC conditions at the amplifier inputs.
Remove the Zener, and if the problem stops, don't put it back.
You can instead use a rail-to-rail op amp working on a single 5V supply.
That way it can't output too much.
Maybe you are upsetting the DC conditions at the amplifier inputs.
Remove the Zener, and if the problem stops, don't put it back.
You can instead use a rail-to-rail op amp working on a single 5V supply.
That way it can't output too much.