Emerging technologies provide SoCs with fine-grained DVFS capabilities both in space (number of domains) and time (transients in the order of tens of nanoseconds). Analyzing these systems requires cycle-accurate accounting of rapidly-changing dynamics and complex interactions among accelerators, interconnect, memory, and OS. We present an FPGA-based infrastructure that facilitates such analyses for high-performance embedded systems. We show how our infrastructure can be used to first generate SoCs with looselycoupled accelerators, and then perform design-space exploration considering several DVFS policies under full-system workload scenarios, sweeping spatial and temporal domain granularity.
This paper presents a 40-MHz hybrid CMOS/GaN integrated multiphase dc-dc switched-inductor buck converter with a maximum 20-V input voltage. The half-bridge switches are realized using lateral AlGaN/GaN HEMTs, while the drivers and other circuitry are implemented in standard 180-nm CMOS. The interface between the CMOS and GaN dice is achieved through face-to-face bonding, reducing inductive parasitics for the connection to less than 15 pH. A capacitively coupled level shifter provides the gate drive for the high-side GaN switch using 5-V CMOS devices. The converter demonstrates 76% efficiency for 8:1 V conversion and over 60% efficiency for conversion ratios up to 16:1. Index Terms-Capacitively coupled level shifter, CMOS/GaN face-to-face bonding, gate drive for GaN, integrated voltage regulator (IVR), power electronics.
Emergingnon-imaging ultrasound applications, such as ultrasonic wireless power delivery to implantable devices and ultrasound neuromodulation, require wearable form factors, millisecond-range pulse durations and focal spot diameters approaching 100 µm with electronic control of its three-dimensional location. None of these are compatible with typical handheld linear array ultrasound imaging probes. In this work, we present a 4 mm x 5 mm 2D ultrasound phased array transmitter with integrated piezoelectric ultrasound transducers on complementary metal-oxide-semiconductor (CMOS) integrated circuits, featuring pixel-level pitch-matched transmit beamforming circuits which support arbitrary pulse duration. Our direct integration method enabled up to 10 MHz ultrasound arrays in a patch form-factor, leading to focal spot diameter of ~200 µm, while pixel pitchmatched beamforming allowed for precise threedimensional positioning of the ultrasound focal spot. Our device has the potential to provide a high-spatial resolution and wearable interface to both powering of highlyminiaturized implantable devices and ultrasound neuromodulation.
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