High precision voltage source for electrical impedance tomography
First Claim
1. An apparatus comprising:
- a plurality of voltage sources for supplying a corresponding plurality of voltages to a corresponding number of other structures;
voltage source calibration means for calibrating each voltage source; and
switching means for individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition;
each voltage source including an operational amplifier having an output and a sense resistor connected to the output of the operational amplifier, each voltage source also including a buffer amplifier having an input connected to the sense resistor for outputting a measured voltage, and an instrumentation amplifier having one input connected to the operational amplifier output and another input connected to the sense resistor for outputting a measured current.
2 Assignments
0 Petitions
Accused Products
Abstract
An EIT system includes a plurality of voltage sources for supplying a corresponding plurality of voltages to a corresponding number of other structures, voltage source calibration means for calibrating each voltage source, and switching means for individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition. Calibrating respective voltages and currents for each voltage source compensates for shunt impedance of each voltage source. A method for calibrating the system includes individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition for calibrating all of said voltage sources in the same way.
-
Citations
20 Claims
-
1. An apparatus comprising:
-
a plurality of voltage sources for supplying a corresponding plurality of voltages to a corresponding number of other structures; voltage source calibration means for calibrating each voltage source; and switching means for individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition; each voltage source including an operational amplifier having an output and a sense resistor connected to the output of the operational amplifier, each voltage source also including a buffer amplifier having an input connected to the sense resistor for outputting a measured voltage, and an instrumentation amplifier having one input connected to the operational amplifier output and another input connected to the sense resistor for outputting a measured current. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for calibrating an apparatus having a plurality of voltage sources for supplying a corresponding plurality of voltages to a corresponding number of other structures, and voltage source calibration means for calibrating each voltage source, the method comprising:
-
individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition for calibrating all of said voltage sources in the same way; each voltage source including an operational amplifier having an output and a sense resistor connected to the output of the operational amplifier, each voltage source also including a buffer amplifier having an input connected to the sense resistor for outputting a measured voltage, and an instrumentation amplifier having one input connected to the operational amplifier output and another input connected to the sense resistor for outputting a measured current, the method including determining a gain for the buffer amplifier. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. An electrical impedance imaging apparatus comprising:
-
a plurality of voltage sources with shunt impedances for supplying a corresponding plurality of voltages to a corresponding number of other structures, each voltage source including an operational amplifier having an output and a sense resistor connected to the output of the operational amplifier, a buffer amplifier having an input connected to the sense resistor for outputting a measured voltage, and an instrumentation amplifier having one input connected to the operational amplifier output and another input connected to the sense resistor for outputting a measured current; voltage source calibration means for calibrating each voltage source; and switching means for individually connecting the calibration means to each voltage source in succession during a period when each other structure is in an inactive condition. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
Specification