US 7,623,053 B2 · Implantable medical device with low power delta-sigma analog-to-digital converter

Abstract

In general, this disclosure describes techniques for reducing power consumption within an implantable medical device (IMD). An IMD implanted within a patient may have finite power resources that are intended to last several years. To promote device longevity, sensing and therapy circuits of the IMD are designed to incorporate an analog-to-digital converter (ADC) that provides relatively high resolution output at a relatively low operation frequency, and does so with relatively low power consumption. An ADC designed in accordance with the techniques described herein utilizes a quantizer that has a lower resolution than a digital-to-analog converter (DAC) used for negative feedback. Such a configuration provides the benefits of higher resolution DAC feedback without having the use high oversampling ratios that result in high power consumption. Also, the techniques avoid the use of, and the associated high power consumption of, a high resolution flash ADC, within the sigma delta loop.

Claims25

Dependent claims

An implantable medical device comprising:

at least one sensor that generates an analog input signal;
at least one delta-sigma analog-to-digital converter (ADC) that converts the analog input signal to a digital signal, the delta-sigma ADC comprising:
an integrator that produces an integrated difference between the analog input signal and a reconstruction of the analog input signal;
a quantizer that produces a control signal based on the integrated difference;
an up/down counter that adjusts a digital value according to the control signal;
a digital-to-analog converter (DAC) that generates the reconstruction of the analog input signal based on the digital value of the up/down counter and provides the reconstruction of the analog input signal as negative feedback to the integrator, wherein a resolution of the quantizer is less than a resolution of the DAC;
and
a compensation module that compensates for a phase shift in the negative feedback caused by the integrator and the up/down counter,
wherein the device further comprises:
a processor that receives the digital signal from the delta-sigma ADC.

7 more elements

Dependencies are inferred from the claim text.

Implantable medical device with low power delta-sigma analog-to-digital converter

Life of this patent

Implantable medical device with low power delta-sigma analog-to-digital converter

Life of this patent

Abstract

Claims25