Ultra-low-power pulse oximeter implemented with an energy-efficient photoreceptor
First Claim
1. A transimpedance amplifier apparatus for providing energy-efficient amplification and feedback conversion of an input-current signal into an output-voltage signal comprising:
- a) a high-gain amplifier connected between an input and an output of the transimpedance amplifier apparatus wherein the high-gain amplifier is comprised of a cascade of at least three successive lower-gain amplification stages; and
b) a feedback network connected between the output and input of the transimpedance amplifier apparatus that determines an overall gain from input to output of the transimpedance amplifier apparatus; and
c) an adaptive-loop-gain means, for adjusting an amount of amplification provided by the high-gain amplifier based on one of the level of the input-current signal, the level of the output signal, and the gain of said feedback network.
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Abstract
An energy-efficient photoreceptor apparatus and a transimpedance amplifier apparatus having high energy-efficiency and low power consumption of which are achieved through multiple distributed gain amplification stages, adaptive loop gain control circuitry and unilateralization, thereby enabling fast and precise performance over a wide range of input-current levels. The high-energy efficiency, robust feedback stability and performance of the present invention can be utilized to achieve sub-milliwatt pulse oximeters and may be employed in other current-to-voltage amplification and conversion applications. The use of analog processing on the outputs of the photoreceptor apparatus also helps lower the overall power of pulse oximeters.
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Citations
53 Claims
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1. A transimpedance amplifier apparatus for providing energy-efficient amplification and feedback conversion of an input-current signal into an output-voltage signal comprising:
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a) a high-gain amplifier connected between an input and an output of the transimpedance amplifier apparatus wherein the high-gain amplifier is comprised of a cascade of at least three successive lower-gain amplification stages; and b) a feedback network connected between the output and input of the transimpedance amplifier apparatus that determines an overall gain from input to output of the transimpedance amplifier apparatus; and c) an adaptive-loop-gain means, for adjusting an amount of amplification provided by the high-gain amplifier based on one of the level of the input-current signal, the level of the output signal, and the gain of said feedback network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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18. A transimpedance amplifier apparatus for providing energy-efficient amplification and feedback conversion of an input-current signal into an output-voltage signal comprising:
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a) a high-gain amplifier connected between an input and an output of the transimpedance amplifier apparatus wherein the high-gain amplifier comprises a cascade of at least three successive lower-gain amplification stages; and b) a feedback network connected between the output and input of the transimpedance amplifier apparatus that determines an overall gain from input to output of the transimpedance amplifier apparatus. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25)
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26. A transimpedance amplifier apparatus for providing energy-efficient amplification and feedback conversion of an input-current signal into an output voltage signal comprising:
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a) a high-gain amplifier, connected between an input and an output of the transimpedance amplifier apparatus, comprised of at least one amplification stage; and b) a feedback network connected between the input and the output of the transimpedance amplifier apparatus that determines an overall gain from the input to the output of the transimpedance amplifier apparatus; and c) an adaptive-loop-gain means for adjusting the amount of amplification provided by the high-gain amplifier based on one of the level of the input-current signal, the level of the output signal, and the gain of said feedback network. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification