The bridge excitation circuit of digital pressure signal conditioner MAX1458

Published:2012/9/25 21:46:00 Author:Ecco | Keyword: bridge excitation , digital pressure, signal conditioner | From:SeekIC

It uses DAC3 output to change the size of the sensor excitation current IBR and achieve fine full-scale calibration. IISRC is reference current which is set by RISRC and the voltage of pin 9. V1 and V2 form a mirror current source, and the current gain is 14 times which enables the excitation current IBR = 14IISRC. The IBR programming range is 0.1 ~ 2mA. The on-off state of analog switches S1, S2 is governed by the configuration register. Obviously, when the full-scale output voltage changes, DAC3 can compensate bridge output voltage by changing BR, thereby correcting the errors of the full scale. DAC4 is used to correct the error of full scale temperature coefficient.



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