Abstract: A charge recycling circuit in an integrated circuit DC-DC converter having two power MOSFETs, the charge recycling circuit comprising a single inductor and recycling MOSFET switches arranged and sized such that when one of the two power MOSFETs is turning off, its gate capacitance charges are transferred to the single inductor, stored in the single inductor and then transferred directly to the gate of the other power MOSFET to turn it on.

Abstract: Disclosed are self-powering biofuel cell and sensor devices, systems and techniques. In some aspects, a self-powered biosensing system includes an electronic circuit; an anode including an enzymatic layer electrically coupled to a power supply voltage terminal of the electronic circuit and configured to interact with an analyte in a fluid, such as glucose or lactate; and a cathode electrically coupled to a ground voltage terminal of the electronic circuit, where the electronic circuit is operable to control and use the electrical energy generated at the anode and cathode for powering the biosensing system and detecting a concentration of the analyte in the fluid.

Abstract: A method for communicating directly with commodity Wi-Fi transceivers (TRXs) via backscatter modulation in an integrated tag device is provided. The method includes sensing an incident Wi-Fi?compliant wake-up signal. The method than reflects the incident Wi-Fi- complaint wake-up signal by encoding data from the tag device such that the reflected signal follows the Wi-Fi standard compliant and can be decoded by another WiFi-device. An integrated device includes a downlink Wi-Fi compatible wake-up receiver that checks timing of Wi-Fi compatible signals for a wake-up packet. The device has a modulator that is turned on in response to the wake-up packet and a mixer in the modulator hat mixes tag data with a payload packet from received Wi-Fi payload. Backscatter switches backscatter the response.

Abstract: Disclosed are systems, devices and methods for continuous and simultaneous monitoring of multiple analytes within interstitial fluid by an integrated system for a microneedle array sensor platform. In some aspects, the device includes a microneedle array sensor unit, an electronics unit and a housing structure. The electronics unit is in electrical communication with an array of electrode probe structures via an array of surface-mount, spring loaded pins, and the electronics unit includes a power source, a data processing unit, and a wireless transmitter. The housing structure is configured to encase, at least partially, the microneedle array sensor unit and the electronics unit, where the array of microneedles is exposed from a side of the housing structure. The device can be configured as a patch worn on skin of a patient user.

Abstract: Apparatuses and methods are disclosed for efficient wireless powering of an electrical load with precise external control over pulsed voltage waveform and metering of charge delivered. The system interfaces to an inductive coil for RF power delivery from an external duty-cycled RF power transmitter, and the electrical load. The electrical load may be a photosensitive array of electrodes for an optically addressed, electrically activated retinal prosthesis. The voltage waveform to activate the load is controlled by the transmitted RF amplitude, including switching between cathodic and anodic phases of electrical stimulation. Charge delivered to the load is quantified as discharge events through a series capacitor, transmitted by backtelemetry to the receiver for continuous monitoring throughout the stimulation phases.

Abstract: A low-power wake-up receiver includes a mixer-based two-stage heterodyne architecture that provides multi-stage channel filtering, including a combination of circuits and a digital signal processor that process energy in a plurality of advertising channels to detect a four-dimensional wake-up signature via frequency-hopping among the plurality of advertising channels. One receiver is a BLE/Wi-Fi dual-mode wake-up receiver.

Abstract: A charging to digital converter sensor in a CMOS integrated circuit digitizes a sensed property by comparing charging time between two paths and adjusting the charging rate of one of the two paths by increasing or decreasing the amount of capacitance in that path, until both of the two paths have the same charging time to reach respective constant with sensed property and proportional with sensed property reference voltages or currents. Sub nanowatt operation is achieved with preferred circuits. A method directly digitizes, on-chip, a charging time comparison of two ramp voltages that are compared to respective constant with sensed property and proportional with sensed property reference voltages or currents.

Abstract: A DC-DC converter converts voltage from a battery source providing a voltage Vin to a lower level. A four-level transistor stack selectively connects an input voltage and flying capacitor voltages to an output inductor. Stress reduction transistors limit the charging of the flying capacitors to Vin/3. The stress reduction transistors can also limit switching transistor voltages to Vin/3. Freewheel switches can be used to limit ringing in the output inductor.

Abstract: An ultra-low-power voltage reference generator in an integrated CMOS circuit includes a regular MOS transistor reference current source connected to a line voltage and a regular MOS transistor resistor between the regular MOS transistor reference current source and ground. A constant with temperature reference voltage VREF is generated from a terminal inter-connecting the regular MOS transistor reference current source and the regular MOS transistor resistor. An ultra-low-power current reference generator receives a reference voltage and generated ultra-low level current from the reference voltage with a temperature compensated gate-leakage array.

Abstract: A transmitter for a magnetic body area network includes a power oscillator that directly uses a body coil as a resonant element. Shunt transistor circuitry is between the power oscillator and the body coil, the shunt transistor circuitry selectively shunts current from the body coil in response to a data signal provided to the transmitter. Power injection circuitry is synchronized to the power oscillator to selectively inject power into the body coil in response to the data signal. A tuning capacitor array is disposed to tune frequency in the body coil. A frequency-locked-loop responds to a frequency in the body coil and tunes the tuning capacitor array to lock to a carrier frequency. Very high Q coils can be used while achieving high data transmission rates of 5 mbps to 10 mbps. Transmitters and methods are applicable to on-off-key modulation, frequency-shift modulation and amplitude-shift modulation.

Abstract: Methods, systems, and devices are disclosed for wearable, real-time multimodal sensing of electrochemical and electrophysiological and/or physical parameters of a user. In some aspects, a multimodal sensor device includes a flexible substrate; an electrochemical sensor disposed on the substrate and including electrochemical sensing electrodes operable to measure an electrical signal corresponding to a reaction including a chemical substance via an electrochemical sensing electrode and an analyte at the electrochemical sensor; and an electrophysiological sensor including two or more electrodes disposed on the substrate to acquire an electrophysiological signal of the user, such that when the multimodal sensor device is electrically coupled to an electronics unit and adhered to the user, the device is operable to simultaneously monitor an electrochemical parameter and an electrophysiological parameter of the user.

Abstract: A system includes an implanted autonomous microchiplet communicatively linked to an epidermal skinpatch having a transceiver and a demodulator, an intermediate device communicatively linked to the epidermal skinpatch, the intermediate device configured to receive neural signals for decoding from the epidermal skinpatch and to send encoded signals for patterned stimulation to the epidermal skinpatch, and one or more external devices communicatively linked to intermediate device.

Abstract: A charging to digital converter sensor in a CMOS integrated circuit digitizes a sensed property by comparing charging time between two paths and adjusting the charging rate of one of the two paths by increasing or decreasing the amount of capacitance in that path, until both of the two paths have the same charging time to reach respective constant with sensed property and proportional with sensed property reference voltages or currents. Sub nanowatt operation is achieved with preferred circuits. A method directly digitizes, on-chip, a charging time comparison of two ramp voltages that are compared to respective constant with sensed property and proportional with sensed property reference voltages or currents.

Abstract: A non-invasive epidermal electrochemical sensor device includes an adhesive membrane; a flexible or stretchable substrate disposed over the adhesive membrane; and an anodic electrode assembly disposed over the flexible or stretchable substrate including an iontophoretic electrode. The device includes a cathodic electrode assembly disposed adjacent to the anodic electrode assembly over the flexible or stretchable substrate and includes an iontophoretic electrode. Either the cathodic electrode assembly or the anodic electrode assembly also includes a sensing electrode that includes a working electrode and at least one of a counter electrode or a reference electrode. The iontophoretic electrode in either the anodic electrode assembly or the cathodic electrode assembly that includes the sensing electrode is disposed on the substrate to at least partially encompass the working electrode and the at least one of the counter electrode or the reference electrode.

Abstract: A fast startup power oscillator transmitter includes a transistor pair that drives a resonant circuit including a tunable capacitance. A capacitor array preferably forms the tunable capacitance. A voltage booster activates the capacitor array. A clamped body bias voltage booster can set the body bias voltage of the transistor pair in one circuit. Control circuitry activates the resonant circuit through a triode-mode switch transistor in response to an input in a range of 0.3-0.6V, and preferably while controlling the substrate bias voltage of the transistor pair to increase transconductance of the cross-coupled transistor pair. In a variation, a circuit pushes a top plate voltage of one of the two capacitors to 2VDD and pulls the top plate voltage of the other to zero to give the oscillator an initial condition.

Abstract: A charging to digital converter sensor in a CMOS integrated circuit includes a sensor responding to a sensed property, a converter that converts the sensed property into a charging time, a digitizer for digitizing the charging time, and digital feedback to reset the converter to restart the charging time. Preferred methods for sensing match the rising time of the first ramp voltage to a second ramp voltage generated by a reference current mirrored from a common current generator via the tuning of DAC capacitors driven by an LSB-first SAR logic feedback; or match rising times of the first and second ramp voltages to a reference voltage and providing a digital signal that translates the relationship of the first ramp voltage and the reference voltage to a digital quantification of the sensed property.

Abstract: A fast startup power oscillator transmitter includes a transistor pair that drives a resonant circuit including a tunable capacitance. A capacitor array preferably forms the tunable capacitance. A voltage booster activates the capacitor array. A clamped body bias voltage booster can set the body bias voltage of the transistor pair in one circuit. Control circuitry activates the resonant circuit through a triode-mode switch transistor in response to an input in a range of 0.3-0.6V, and preferably while controlling the substrate bias voltage of the transistor pair to increase transconductance of the cross-coupled transistor pair. In a variation, a circuit pushes a top plate voltage of one of the two capacitors to 2 VDD and pulls the top plate voltage of the other to zero to give the oscillator an initial condition.

Abstract: A method and device for wireless power transfer provide the ability for concurrent power transfer on two widely separated bands. A wireless power transmitting device includes two coils respectively configured for transmission at two separate wireless power transmission frequencies. A dedicated current or voltage driver is provided for each of said two coils. A controller causes the current or voltage drivers to selectively or concurrently generate an AC magnetic field at either of the frequencies or both frequencies. A method includes concurrently driving two coils arranged with respect to each other to reduce losses at two separate wireless power transmission frequencies while suppressing eddy currents in the path of one of the two coils.

Abstract: Methods, systems, and devices are disclosed mouth-based biosensors and biofuel cells. In one aspect, an electrochemical sensor device for detecting analytes in saliva includes a substrate including an electrically insulative material, a first electrode disposed on the substrate at a first location, in which the first electrode includes a surface including a chemical agent (e.g., a catalyst or a reactant) corresponding to an analyte in saliva; and a second electrode disposed on the substrate at a second location separated from the first electrode by a spacing region, the first and second electrodes capable of sustaining a redox reaction involving the chemical agent and the analyte to produce an electrical signal, such that, when the device is present in the mouth of a user and electrically coupled to an electrical circuit, the device is operable to detect the analyte in the user's saliva.

Abstract: A system includes an ensemble of wirelessly networked intracranial implants, and a compact external epidermal wearable skin patch radio frequency (RF) transceiver and data processing hub, the network of intracranial implants wirelessly linked to the skin patch RF transceiver and data processing hub.