I had been hoping to use the TPA3116D2 to drive an unusual load of about 180 uH but only about 0.4 ohms of resistance (8 times less than the 3.2 ohms recommended in the data sheet), restricting input voltage amplitude such that the output current amplitude would not exceed what would be encountered with a normal 4 ohm load at full-scale voltage output swing. [In theory, most of the power dissipated by the output MOSFETs = 2 * IOUT2 * RDS(ON), regardless of load impedance.] I know that the TPA3116D2 has certain thermal protection features, but I still managed to permanently damage one when using one channel of a TPA3116D2EVM (including its output filtering) to drive such a load.
Is there any guidance available for driving unusual loads?
What would be the limiting/disqualifying factors? Could fly-back voltage kicks from a high-inductance load during PWM switching (after passing backwards through the TPA3116D2EVM's output filters) damage the body diodes or gate oxides of the output MOSFETs? Could instantaneous output currents occurring during PWM switching produce damaging thermal transients even when the average power dissipated was quite low?
Any insights would be appreciated.
Regards,
Dan
