I am developing a DAQ using PSOC 3 and I have 2 strain guage sensers I want to power them using the Kit. the power requirement is DC 12(10.5~15)V 30mA MAX for the first sensor. and DC 24(21~30)V 30mA MAX for the other one.
Please help me doing this.
As I understand you cannot power the sensors with your kit except switching the sensor's supply using a relay or something similar.
You will need to shift the sensor's outputs to the range the PSoC is powered with which is 0 to 5V or 0 to 3.3V
The link in the prior post will be of no help if its traditional bridge type strain
Post a link to your sensor datasheet so we can look at the requirements further.
Generally speaking you if you can run the sensor at a lower V then
you can get the bridge connections CM range into the PSOC A/D
CM range. which for a 5V part is roughly 5V. Key to the design is
what sensitivity the sensor has.
Some questions -
1) Resolution of the system you are seeking ?
2) Absolute accuracy desired in system ?
3) Dynamic range of system ?
4) Is your system power at 12V and you derive PSOC Vdd off that or
do you need to develop the 12 V seperately ?
5) Sensor a raw sensor or is it internally signal conditioned ? Link to datasheet
will answer this.
If you have to run the bridge at 12V then you will need an external IA
to handle the diff mode CM range G needed and level shift.
Some useful references -
A simple boost regulator, charge pump or L based.
You could roll your own, using a PSOC comparator in a Hysteretic configuration,
one of the simplest architectures.
TI, LTC, On, Fairchild, tons of solutions out there, even low power stuff, most
A good place to go is TI/NSC Webench design tool, very easy to do a design with
schematic generated and thermals considered.