Ultrasound imaging or other use variable input impedance preamplifier
AssigneeSiemens Medical Solutions USA, Inc.
InventorsKevin Randall, James Edelen
Life of this patent
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Abstract
A preamplifier has a variable input impedance. The input impedance is tailored with the signal level to maintain a more optimal performance. The input impedance is varied by at least two amplifiers connected in parallel. Each amplifier has a different input impedance. By controlling the bias currents to the amplifiers, the contribution to the input impedance of the parallel amplifiers is controlled. Gradual variation in input impedance may be obtained by gradual variation in relative contribution by the different amplifiers.
Claims22
A variable input impedance preamplifier for ultrasound imaging, the preamplifier comprising:
- a higher input impedance amplifier;
- a lower input impedance amplifier connected in parallel with the higher input impedance amplifier;
- and
- an ultrasound transducer connected with the higher and lower input impedance amplifiers.
A variable input impedance preamplifier, the preamplifier comprising:
- a higher input impedance amplifier;
- a lower input impedance amplifier connected in parallel with the higher input impedance amplifier;
- and
- a control circuit connected with the higher and lower impedance amplifiers, the control circuit operable to control an input impedance of the preamplifier in conjunction with a variance in gain of the preamplifier.
A method for varying an input impedance of a preamplifier used for ultrasound imaging, the method comprising:
- transitioning contribution to the input impedance of the preamplifier from a lower input impedance amplifier to a higher input impedance amplifier as a function of time, the lower and higher input impedance amplifiers being connected in parallel;
- and
- amplifying ultrasound signals with the preamplifier while transitioning.
Dependencies are inferred from the claim text.