TPS7A85: Connection to Microcontroller

Conrad Hopp

Part Number: TPS7A85

I am an undergraduate at the university of Toronto and I am wondering if it is possible to control the pins on this component using a micro controller to adjust the output voltage.

If not, can anyone recommend a linear regulator that can be adjusted using a microcontroller?

Thanks!

Conrad

over 8 years ago

0 JCHK over 8 years ago

TI__Guru 50190 points

Hi Conrad,

Yes. As long as the MCU has open-drain outputs you can control the Vout of the LDO with the Any-Out pins.

These pins add to the reference voltage only when pulled to GND.

I hope th8s answers your question.

Regards,

0 Conrad Hopp over 8 years ago in reply to JCHK

Prodigy 70 points

Hi John,

Thanks for the response. 1 more thing - can it produce a sinusoidal varying voltage driven by the MCU?

Thanks again!

Conrad

0 JCHK over 8 years ago in reply to Conrad Hopp

TI__Guru 50190 points

Hi Conrad,

The Any-Out pints can control Vout in in 50mV steps from 0.8V to 3.95V. So you can approximate a sinusoid . One thing to keep in mind, the TPS7A85 can only source current. It can not sink. So Vout will only fall if there is a load on Vout.

Does this make sense?

Regards,

0 Conrad Hopp over 8 years ago in reply to JCHK

Prodigy 70 points

Hi John,

Okay this makes sense.

kind of off topic here but I'm going to be connecting this with a VCO. can we control the voltage and frequency output with the VCO??

Thanks again,

Conrad

0 Conrad Hopp over 8 years ago in reply to Conrad Hopp

Prodigy 70 points

And also, do you know what the efficiency of this regulator is?

0 JCHK over 8 years ago in reply to Conrad Hopp

TI__Guru 50190 points

HI Conrad,

I am not sure how you would be using the VCO. Here is a link to an application note using an I/O expander to control Any-Out(TM):

I hope this helps.

Regards,

0 JCHK over 8 years ago in reply to Conrad Hopp

TI__Guru 50190 points

Hi Conrad,

An LDO efficiency is pretty much Vout/Vin. Actually it is Vout*Iout/(Vin*(Iout+Iq)) where Iq is the quiescent current of the LDO,.

Regards,

Power management

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TPS7A85: Connection to Microcontroller