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TPA2038D1YFFEVM: Can we use Output of Class D integrated in ISD 2100 to driver our TPA2038D1?

Part Number: TPA2038D1YFFEVM
Other Parts Discussed in Thread: TPA2038D1

Hi team,

This is Alix of Beijing auto team. My customer Foton is considering use our TPA2038 to driver their speaker in their reversing alarm system.

However, though it is a AIN amplifier, the input signal of TPA2038 EVM is differential PWM signals (without filter) from output of class D integrated in ISD2100 . As

is shown bellow:

 As to figure above, SPK+ and SPK- are directly connected to input pins of  TPA2038 EVM. SPK+ and SPK- are PWM signals varying between 0-3.6V while Vsupply of TPA2038 is 5V. The aim is to amplify the signal up to 3W@3.1ohm;

On my side, this is equivalent to using a class D to drive another class D. Audio signal is modulated in PWM(SPK+ and SPK-), if we use a filter to filter the PWM out and use analog signal as input signal of TPA2038? Do it work? without considering the quality of the sound conditions, such a program feasible? How about TPA6211?

Problem:

At present, the test indicates that TPA2038 cannot amplify the signal more than 0.4W.  In addition, 6dB or 12dB gain setting does not work.

Do you have any ideas about this problem? Thanks ahead!

  • Hi Alix,

    This device is designed to work with an audio input signal (sine waveform). You could add a low-pass RC filter between ISD2100 and the TPA2038D1 to get an analog signal (sine waveform) and it would also help to avoid out-of-band noise. You can refer the following application report: SLAA313 to find further information.
    On the other hand, this device was designed to work with loads higher than 4ohms if you use 3.1ohms the device could be damaged.

    Best Regards
    José Luis Figueroa
    Audio Applications Engineer