TINA/Spice/BQ25504: TINA/Spice/BQ25504

Aparrnaa Krishnamurthi

Part Number: BQ25504
Other Parts Discussed in Thread: TINA-TI, BQ25505,

Tool/software: TINA-TI or Spice Models

Hi all,

I am doing RF energy harvesting research in Chemnitz University of Technology, Chemnitz, which can supply a sensor node through a boost converter. DC-DC boost converter is BQ25504. I have BQ25504 PCB which gives 3.6V, but for the sensor the voltage is high

My sensor node consumes 1.5V at 60µA of current, So i had to design BQ25504 PCB with 1.5V±0.2V with a current of 60µA. and another requirement is 2.6V from BQ25504 for supplying batteries.

Could you please help me in designing the PCB for BQ25504 with the above said requirements, (simulation is not important), it will be very helpful for my research.

Thank you

Regards

Aparrnaa

over 7 years ago

0 Robin Tang over 7 years ago

TI__Prodigy 670 points

You may want to set an appropriate VBAT_OV threshold to make teh voltage is what you want in your application.

0 Aparrnaa Krishnamurthi over 7 years ago in reply to Robin Tang

Prodigy 70 points

Hi Robin,

I want to set VBAT_Ok value to 1.5V, but in the document it is given given Minimum recommended voltage is 2.5V , is it possible to reduce it to 1.5V? If it is possible please suggest the values for Rok1, Rok2,Rok3, Ruv1,Ruv2, Rob1, Rov2 and Cstor values.

Thanks and Regards

Aparrnaa

0 Robin Tang over 7 years ago in reply to Aparrnaa Krishnamurthi

TI__Prodigy 670 points

Hi Aparrnaa,
The 1.5V VBAT_OK is out of the bq25505 normal operation range, we don't recommend customer to set such low threshold.
Thanks,

0 Aparrnaa Krishnamurthi over 7 years ago in reply to Robin Tang

Prodigy 70 points

Hi Robin,

Thank you for your reply, if 1.5V is not recommend then is it possible to get 1.8V at VSTOR as given in graphs in page number 7,8 in BQ25504 document.

Thanks and regards
Aparrnaa

0 Robin Tang over 7 years ago in reply to Aparrnaa Krishnamurthi

TI__Prodigy 670 points

Hi Aparrnaa,
What's mean the page number 7,8 ? It just some waveforms in page 7/8 in bq25504 datasheet. Can you clarify it?
Thanks,

0 Aparrnaa Krishnamurthi over 7 years ago in reply to Robin Tang

Prodigy 70 points

Hi Robin,

In page number 7 the graphs were drawn between input voltage and efficiency for various VSTOR voltages like 5.5V, 3.3V, 1.8V. I have the circuit which can give 3.1V at VSTOR,1_BQ25504_TINA_TI_up.TSC (i am attaching the circuit, please find the attachments.), can you suggest modifications for the circuit to get VSTOR=1.8V voltage

Thanks and regards

Aparrnaa

0 Robin Tang over 7 years ago in reply to Aparrnaa Krishnamurthi

TI__Prodigy 670 points

Hi Aparrnaa,
Thanks for your clarification, for these curves we used the Keithley Sourcemeter as the VSTOR, that use Keithley Sourcementer to hold teh VSTOR voltage as 1.8V, 3.0V or 5.5V

0 Aparrnaa Krishnamurthi over 7 years ago in reply to Robin Tang

Prodigy 70 points

Hi Robin,

I am confused now, VSTOR is the output of Bq25504, why applying from source meter at VSTOR.

My only requirement is to get 1.8V as output either from VSTOR or VBAT. Please help me in this regard.

Thanks

0 Robin Tang over 7 years ago in reply to Aparrnaa Krishnamurthi

TI__Prodigy 670 points

Hi Aparrnaa,

The 1.8V/3V plots demonstrate the efficiency of the boost converter, Yes VSTOR is the output, if VSTOR voltage is greater than 1.8V, then the charger is active and the VBAT=VSTOR. We just set the VBAT voltage, that is VBAT_UV, VBAT_OV, we don't to set the VSTOR voltage, you cannot think it as a normal boost regulator.

Thanks,

0 Aparrnaa Krishnamurthi over 7 years ago in reply to Robin Tang

Prodigy 70 points

Hi Robin,

Thanks for clarifying. my last question is, is there anyway to get 1.8V at VBAT.

Thanks

Aparrnaa

0 Robin Tang over 7 years ago in reply to Aparrnaa Krishnamurthi

TI__Prodigy 670 points

Hi,

If 1.8V at VBAT, then in normal mode the VSTOR voltage should be also near 1.8V, but this voltgae is undert the VBAT_UV, the internal PMOS between VSTOR adn VBAT will not turn on, so you can get a stable 1.8V, as I said before it out of the range.

Thansk,

Power management

Power management forum

TINA/Spice/BQ25504: TINA/Spice/BQ25504