Best power supply design for adc

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PaSv_1652016
Level 2
Level 2
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Hello COMMUNITY 8))

please  give me recommendations about suply

i have :

Psoc 5lp for ~16-18bit ADC and postprocessing

full Isolated dif amp (TI amc1301) for measure current  shunt.

Shunt located in heavy EMI from random ultra HV sparks.

for power supply device i  want use  1s Lipo 2x18650 3500mah

device shilded in metall  box

i need maximum ADC  perfomance  for my situation , and long battery life.

in this case i have some questions:

1. can i supply PSOC (Vddd= 3.3-4.2v) direct from LIPO without LDO, or best way  use buck/boost regulator for full lipo dicharge to 3.0 V , and stabil 3.3 main voltage?

2. how i understand, for accurate ADC measurement i need external Vref.
in this case  i can use dual Vref ic TI REF2033 (1.65V20mA + 3.3V20mA, 6 ppm/°C ,  Accuracy: ±0.05% ).

REF2033 out1  Vref 3.3 ->  to PSOC Vdda + amc1301 Vdd2
REF2033 out2 Vref 1.65 -> to PSOC Vref

or you can tell me a more optimal solution ?

3. isolated DCDC for isolated amp parts + 3.3 LDO to amc1301 Vdd1 

ADUM6000 or any other 1:1 isolated DCDC

.

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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

PaSv,

"16-18bit ADC" and "random ultra HV sparks" do not come along. Data collected during the sparks, has to be discarded.

PSoC5 has internal 1.024V reference, which is sufficient for 16-18-bit DelSig_ADC measurements. I don't believe that any improvement can be made using external voltage reference, particularly in noisy EMI environment.

 

Simple data acquisition by PSoC5 will draw about 30mA,  a pair of 18650 3500mAH each will run the system for 10 days continuously. I would use batteries directly, without any DC-DC converter. Voltage variation 4.2 down to 3.3V should not be an issue.

/odissey1

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