Justin Vogt - Academia.edu (original) (raw)

Papers by Justin Vogt

Distributed, self-powered, micro-scale, wireless sensor networks promise to revolutionize largesc... more Distributed, self-powered, micro-scale, wireless sensor networks promise to revolutionize largescale systems, changing the way they are studied, built, monitored, and controlled. Distributed, self-powered, micro-scale, wireless sensor networks promise to do for large-scale systems what the integrated circuit (IC) did for computers and portable devices, changing the way they are studied, built, monitored, and controlled. In biomedical applications, encapsulated sensors can be implanted or swallowed to monitor various body functions and deliver medication on-demand. Industrial systems could distribute sensors throughout a plant or facility to accurately and uniformly control humidity, temperature, and countless of other parameters, and even perform system prognosis and initiate self-healing sequences. Sensors used in military vehicles can gather security-threatening information, such as the presence of toxic, explosive, or electromagnetic interference (EMI), to not only warn and automatically react but to also study the way systems behave once they are deployed in the field, allowing next-generation designers to improve the way the systems are built. Key enabling attributes to this technology are its high sensor-density and non-invasive features, which present challenges in the form of integration (including micro-scale energy sources); efficient power-conditioning microelectronics; and micro-Watt, load-managed transceivers, sensors, and supporting circuits, the composite of which is illustrated, in general form, in Figure 1.

Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into ... more Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into small spaces, and remain inconspicuous to the body. The problem is that, while including a battery large enough to sustain a system through its entire life impedes integration, under-sizing its energy reservoir to fit into a miniaturized platform shortens operational life. Fortunately, harvesting energy saves space because the environment (not the device) stores the energy a system requires. Harvesters, however, generate little power per unit volume so implantable sensors must operate under stringent power constraints. For this reason, this paper presents a 1.3-�W, 0.6-�m CMOS current– frequency (I–F) analog–digital converter (ADC). The differential, hysteretic-based ADC proposed uses nA-range input currents to set and compare voltage oscillations against a self-produced reference to resolve the input level an amperometric glucose sensor generates. The prototyped ADC ultimately draws 1.1...

While the first two functions are essential to switching power supplies, the latter has universal... more While the first two functions are essential to switching power supplies, the latter has universal applications. Mixed-signal circuits, for instance, typically incur clock-synchronized load-current events that are faster than any active power supply circuit can supply, and do so while only surviving small variations in voltage. The result of these transient current excursions is noisy voltages, be they supply lines or data links. Capacitors are used to mitigate these effects, to supply and/or shunt the transient currents the power supply circuit is not quick enough to deliver, which is why a typical high performance system is sprinkled with many nanoand micro-Farad capacitors.

Distributed, self-powered, micro-scale, wireless sensor networks promise to do for large-scale sy... more Distributed, self-powered, micro-scale, wireless sensor networks promise to do for large-scale systems what the integrated circuit (IC) did for computers and portable devices, changing the way they are studied, built, monitored, and controlled. In biomedical applications, encapsulated sensors can be implanted or swallowed to monitor various body functions and deliver medication on-demand. Industrial systems could distribute sensors throughout a plant or facility to accurately and uniformly control humidity, temperature, and countless of other parameters, and even perform system prognosis and initiate self-healing sequences. Sensors used in military vehicles can gather security-threatening information, such as the presence of toxic, explosive, or electromagnetic interference (EMI), to not only warn and automatically react but to also study the way systems behave once they are deployed in the field, allowing next-generation designers to improve the way the systems are built. Key enabl...

The natural but unwelcome byproduct of modern telecommunication systems is electromagnetic interf... more The natural but unwelcome byproduct of modern telecommunication systems is electromagnetic interference (EMI). These communication networks are dynamic and produce unpredictable positionand time-varying electromagnetic fields that interfere with sensitive high-performance electronics, for which shielding is often a necessity. The shield’s ability to suppress electromagnetic noise, however, may change not only over time but also across environmental conditions. EMI sensors, as a result, play a critical role because arbitrarily over-sizing a shield to accommodate worst-case conditions is not an option in many

2007 50th Midwest Symposium on Circuits and Systems, 2007

Emerging ad-hoc wireless sensor nodes and other micro-scale applications demand long operational ... more Emerging ad-hoc wireless sensor nodes and other micro-scale applications demand long operational lives, small form factors, and total integration, which are next to impossible to fully achieve with conventional battery technologies. Efficient, power-moded, fully integrated systems inherently demand high peak-to-average power ratios (PAPRs), as in wireless sensor applications where telemetry is a power-consuming function with low duty-cycle operation. Lithium ion batteries (Li-Ion), while conforming to micro-scale dimensions and supplying moderate power densities, cannot store enough energy to sustain extended lifetimes, which is where fuel cells (FCs) excel. Although various control strategies for energy flow between batteries and FCs have been proposed in the past, none of them superimpose the severe constraints of a micro-scale system on the design, where volume, energy, and power are scarce and the performance of the MEMS FCs degrade with time. This paper presents a hybrid micro-scale MEMS FC-thin-film Li-Ion source and proposes a design methodology for the same wherein volume, energy, and power are optimized for peak-power and extended-lifetime performance. The FC is ultimately used to both charge and supply the load asynchronously, depending on the state of the load, while the Li Ion mostly functions as a power cache. System simulations of a multi-sensor wireless system load show and validate how peak-power, average-power, duty-cycle, and frequency performance are achieved and how they relate to lifetime.

… Microcircuit Applications and …, 2007

This paper presents the key design challenges encountered in system-in-package (SiP) wireless sen... more This paper presents the key design challenges encountered in system-in-package (SiP) wireless sensors. These sensors show tremendous promise for the test and evaluation of military equipment. These sensors should be small and autonomous to maximize utility; in this environment, energy management and system integration pose the greatest challenge. Fundamental limits exist on the amount of power required to process and transmit a signal a given distance with given accuracy, and approaching those limits requires careful energy use. Incorporating all necessary components on-chip or inpackage will require examining the trade-offs between volume and energy in many cases, as well as processing and packaging technology limitations. To illustrate these constraints, they are evaluated in the context of designing an EMI sensor.

AEU - International Journal of Electronics and Communications, 2012

Journal of Low Power Electronics, 2012

Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into ... more Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into small spaces, and remain inconspicuous to the body. The problem is that, while including a battery large enough to sustain a system through its entire life impedes integration, under-sizing its energy reservoir to fit into a miniaturized platform shortens operational life. Fortunately, harvesting energy saves space because the environment (not the device) stores the energy a system requires. Harvesters, however, generate little power per unit volume so implantable sensors must operate under stringent power constraints. For this reason, this paper presents a 1.3-W, 0.6-m CMOS currentfrequency (I-F) analog-digital converter (ADC). The differential, hysteretic-based ADC proposed uses nA-range input currents to set and compare voltage oscillations against a self-produced reference to resolve the input level an amperometric glucose sensor generates. The prototyped ADC ultimately draws 1.1 A from a 1.2-V supply to resolve 0-32 nA with 4.25 bits of accuracy at a sampling rate of 225 Hz, which relatively simple and well-understood circuit and layout modifications can improve accuracy to over five bits.

2007 50th Midwest Symposium on Circuits and Systems, 2007

… Microcircuit Applications and …, 2007

AEU - International Journal of Electronics and Communications, 2012

Journal of Low Power Electronics, 2012

Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into ... more Blood-glucose monitors, like many biomedical implants, must operate autonomously, integrate into small spaces, and remain inconspicuous to the body. The problem is that, while including a battery large enough to sustain a system through its entire life impedes integration, under-sizing its energy reservoir to fit into a miniaturized platform shortens operational life. Fortunately, harvesting energy saves space because the environment (not the device) stores the energy a system requires. Harvesters, however, generate little power per unit volume so implantable sensors must operate under stringent power constraints. For this reason, this paper presents a 1.3-W, 0.6-m CMOS currentfrequency (I-F) analog-digital converter (ADC). The differential, hysteretic-based ADC proposed uses nA-range input currents to set and compare voltage oscillations against a self-produced reference to resolve the input level an amperometric glucose sensor generates. The prototyped ADC ultimately draws 1.1 A from a 1.2-V supply to resolve 0-32 nA with 4.25 bits of accuracy at a sampling rate of 225 Hz, which relatively simple and well-understood circuit and layout modifications can improve accuracy to over five bits.