DAC63004: design a new board with using a precision DAC (SBAA341A) and Precision, low-side current measurement (sboa169b)

Alexandre,

We also have the DAC63002 which is a 2-channel version of the DAC63004. But yes, the DAC63004 can control the output of the TPS7A90 and TPS7A8300 using the method presented in SBAA341A. You'll need to calculate R1, R2, R3, and the DAC output range that gives the LDO output range you want. 

Are you also proposing to make the current measurement with the DAC?

Best,

Katlynne Jones 

good morning Katlynne,

I think to take the INA296A with the configuration High-side current because the power supply for first component is 0.8V to 2V0 and its consumption is 10µA to 200µA. And for second component the power supply is between 3V3 to 4V2 and its consumption is 300mA to 1500mA.

One Output of the DAC63004 can to set the amplifier's output voltage ! What do you think ?

thanks for reply 

Alexandre

Dear Katlynne,

I have another idea, I would need an amplifier with programmable gain from G = 10V/V to 1000V/V if I want to use the same sense resistor, I found this amplifier OPA186. Do you have amplifiers with programmable gain? 

thanks 

alexandre

Dear Katlynne,

I found this component ref TMUX1113, maybe you have a better solution to propose me ?

thanks Alexandre

Hi Alexandre,

I'm not understanding where the DAC fits in the high side current sense circuit. The current change through the sense resistor is what changes the output of the op amp. You are using the DAC to control the two output ranges of the two LDOs, is that right? Are you trying to measure the load current IOUT of the LDOs? And the concern is that the VOUT is also changing? 

We do have programable gain amplifiers. You can view our product portfolio here and filter by what specs you need. If you have specific questions about those I can move this request to the team that supports them. 

https://www.ti.com/amplifier-circuit/pga-vga/overview.html

Best,

Katlynne 

Dear Katlynne,

Yes I want to measurement the Iout of the LDOs. But amplifier 's voltage is fixed at 3V3 and I use to one DAC's output for tuning the middle range voltage on ADC's input of the my MCU.

Good day

alexandre

Dear Katlynne,

I understand your note onto : Are you trying to measure the load current IOUT of the LDOs? And the concern is that the VOUT is also changing ?

--> Yes you are right but I would like to use my ADC's input of the MCU or so I must use to ADC after PGA see below: solution 2.

I found the ADS7948SRTET or ADCS7476AIMFX/NOPB or TLA2518IRTER in stock. I think that TLA2518IRTER is good ADC because It has 8 channels !

Thanks for your return

alexandre

Dear Katlynne,

for the PGA I found the PGA117AIPWR or the OPA3S328 in stock! I think to take the OPA3S328. Sorry for previous schematic, the voltage for PGA is 5V0 solution 2).

thanks for your return

alexandre

Hi Alexandre,

I understand the purpose of the DAC in the INA296 circuit now, thanks for drawing it out. You could consider using the low side configuration so the measurement is not supply dependent. Is there a reason you chose the high side configuration?  

For the ADC selection, consider the signal resolution that you want to be able to read. The TLA2518 is 12-bit but uses VDD as the reference. If VDD is 3.3V then the step size is 0.8mV. Make sure this is an acceptable resolution for the current you are trying to measure based on the output range of the current sense circuit. 

Best,

Katlynne Jones