TAS2781EVM: .PPC3 setting for max current output

HI Jose, 

Please see the attached ppc3. i used 2 own purely resistive load and some banana cables which contribute ~200mOhms. with 12V I was able to see ~4.5A on the output, measured from the I-sense data and did not trip the over current protection. if I increase the supply voltage then i will start to have an OC error.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/6/TAS2781_5F00_2Ohm_5F00_12VPVDDH.ppc3

what exactly are you trying to accomplish? is this an audio application, or do you need constant output at full scale into 2 Ohm loads. because while the device can drive ~5A peak into 2 ohms it cannot do it continuously as the die will heat and the device will pullback to prevent burning itself. if you need sustained output at 3Arms an external heat sink, or a higher power device will be needed.

Regards,
Arthur

Hi Arthur,

thanks for looking into this. I will try the file attached.

We are currently developing this fuse/recloser circuit breaker that will be release soon. this product harvest the primary current to charge the internal capacitor storage  using a current transformer. as part of its accessories to aid service technicians, we are developing this charger (tas2781) that will inject different magnitude of current and range of frequency. A stable <1A is needed not to trip the protection and would allow technicians to connect to the device using BLE and make adjustments, hence we required the IV sense to regulate the current. the higher current is for prolong charging of the unit before installations.

I will be definitely consider heatsinking the device on the final PCB. 

Jose

Hi Jose,

thank you for the explanation i more or less understand what you are doing here. but basically, it is not a amplifier driving a speaker, but rather you need the device as a high current driver with current sense. 

the first thing i would recommend is you do not need TAS2781. you are paying extra money for an internal DSP and speaker algorithms that will go unused. what you want is TAS2780. same analog performance, package/pinout , and voltage/current sense, but you are not paying for the DSP. 

furthermore, I discussed with a college and the heat sink won't be very effective on this device as there is no exposed thermal pad on the top of the package. there will likely be enough thermal resistance that a heat sink won't be able to effectively conduct heat out. 

it may be worth your time to make another post to the motor drivers E2E forum. i am not very familiar with the portfolio, but they will certainly have devices which have current sense and top thermal pads, and many amperes of capability. (not sure if they can do a sinewave drive if that is a requirement)

you may also like TAS6584-Q1 which will have the same basic functionality as TAS2781, but it can handle more current.

Regards,
Arthur

Hi Art,

the 2781 was initially selected because of its integrated VI sense capability built in into the IC. If there is an equivalent with high power ratings, that would be more like what we want to do.

Im currently looking at this TAS6422-Q1 as a solution but wondering if the two outputs can be tied for more current?. I wondering how match the current is. It has load protection capability but doesnt mention anything about externalizing that measurement thru I2S.

Can paralleling of output between 2 devices or more possible?. has it been done before on audio drivers?.

Jose