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This paper presents merits and feasibility of a new DC/DC Buck converter architecture where parasitic inductance available in a USB cable is utilized for energy storage element in an example mobile battery charger application. In this proposed architecture, strategizing the cable as inductor and the converter's active devices at the cable's input side enables inductor heat spread along the cable that...
As desired in mobile applications, S-Hybrid converter that merges switched-inductor and switched-capacitor operations can significantly relieve on-board thermal issues by distributing heat loss over an input cable and allowing zero onboard inductor. In this architecture, the input cable is used as inductor for power conversion. This paper presents detailed smallsignal analysis of S-Hybrid converter...
• Clear need to have efficient integrated power supply • SC DC-DC converter is a good candidate for both high power density and high efficiency • SC Converter design techniques • Multiphase interleaving for smaller output ripple • More converter topologies • Efficient switch drivers • Parasitics reduction for integrated capacitors • Feedback and regulation • System techniques • More power converter...
This paper presents a DC-DC step-down power conversion architecture that allows a power cable, such as USB cable, to deliver both power transmission and power conversion functions. In this architecture, an S-Hybrid converter topology is proposed to utilize parasitic inductance readily available in the cable for power conversion stage. As a result, the explicit inductor often required in a buck converter...
In this paper, we consider two-hop multi-input multi-output (MIMO) relay wireless systems with energy harvesting. In each hop, transmit antenna selection (TAS)/receive antenna selection (RAS), TAS/maximum ratio combining (MRC), or maximum ratio transmission (MRT)/RAS is employed. Also, a relay harvests energy from the source via either a time switching-based relaying protocol (TSR) or a power splittingbased...
This work demonstrates a RISC-V vector microprocessor implemented in 28nm FDSOI with fully-integrated non-interleaved switched-capacitor DCDC (SC-DCDC) converters and adaptive clocking that generates four on-chip voltages between 0.5V and 1V using only 1.0V core and 1.8V IO voltage inputs. The design pushes the capabilities of dynamic voltage scaling by enabling fast transitions (20ns), simple packaging...
In this paper, we investigate energy-efficiency in antenna selection OFDM-based systems. We show that an OFDM system with conventional antenna selection approaches, including per-subcarrier selection (i.e., selecting antennas independently for each subcarrier) and bulk-selection (i.e., choosing the same antennas for all subcarriers), suffers from a significant loss in energy-efficiency. To achieve...
Substantial improvements in neural-implant longevity are needed to transition brain-machine interface (BMI) systems from research labs to clinical practice. While action potential (AP) recording through penetrating electrode arrays offers the highest spatial resolution, it comes at the price of tissue scarring, resulting in signal degradation over the course of several months [1]. Electrocorticography...
This paper explores a new DC-DC converter design constraint for adaptable systems that target the minimum-energy point (MEP). Traditionally, DC-DC converters have regulated to a fixed output voltage over a wide range of input voltages. For energy-constrained systems that target the MEP, regulating them to a fixed voltage is unnecessary since changes in the output voltage near the MEP have little impact...
This paper proposes per-subcarrier transmit antenna subset selection with power balancing for MIMO-OFDM UWB systems to simultaneously improve the system error performance and increase data rates. The deployment of the per-subcarrier antenna subset selection may result in a power unbalance across antennas, which could cause power amplifiers (PAs) to operate in their non-linear regions. To overcome...
In this paper, we consider lattice reduction (LR) aided linear detection in a DSTTD-OFDM (double space-time transmit diversity-orthogonal frequency division multiplexing) system with antenna shuffling. We first derive an antenna shuffling criterion for the LR-aided DSTTD-OFDM system. Next, we propose a combined reduced-feedback and adaptive LR algorithm by exploiting the correlation between OFDM subcarriers...
Lithium-ion batteries are the dominant power source in mobile devices. However, while the supply voltage required for processors and SoCs has scaled down to ∼1V, the voltage range of this popular battery remains ∼2.9V–4.2V (nominally ∼3.6V). To bridge this voltage difference, off-chip power management ICs are typically required. Despite their high efficiency [1], supporting many independent, high-current...
In this paper, the application of space time block codes in a very high data rate multiband-OFDM ultra-wideband (VHDR MB-OFDM UWB) system, where the Modified Dual Carrier Modulation (MDCM) scheme and Low Density Parity Check codes are deployed, is investigated. First, we present a new table-based mapping approach and derive soft-demapping expressions for the MDCM scheme. We then propose a space-time-frequency...
In this paper, we investigate a multiband-orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) system with very high data rates (VHDR) of several gigabits per second (Gbps). We propose a DSTTD-based VHDR MB-OFDM UWB system by incorporating a double space-time transmit diversity (DSTTD) scheme into the conventional MB-OFDM UWB system. At the receiver, an efficient soft-demapper that...
In this paper, the application of space time trellis codes to multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) systems is investigated. We propose a coding scheme that could fully exploit all the available channel diversity, including space diversity, frequency diversity and inter-subband diversity. Performance of the proposed system is compared with that of the conventional...
This article consists of a collection of slides from the author's conference presentation on fully integrated switched-capacitor for DC-DC conversion. Some of the specific topics discussed include: the special features of multicore processing chips; supply impedance and split planes; on-die voltage conversion; the deployment of switched capacitors; system design and network architecture; and system...
This paper compares the performance of Switched-Capacitor (SC) and inductor-based DC-DC conversion technologies. A metric to compare between the two topologies is discussed, and is used to compare switch utilization. Fundamental limits on utilization of reactive elements developed in the literature for all DC-DC converters are also reviewed and discussed, and this analysis shows that popular SC and...
In this paper, a load-independent converter with freewheeling current feedback, whose output is controlled by a comparator, is presented. This control method is very useful for single-inductor multiple-output (SIMO) converters. A single-inductor bipolar-output (SIBO) converter with the proposed control scheme is implemented in a 0.5 mum power BiCMOS process and uses 3.2 mm2 of die area. The current...
An amplitude modulator for class-E2 EDGE polar transmitters is fabricated in a 0.35mum CMOS process. This hybrid switching modulator consists of a class-D amplifier with a 2MHz switching frequency and a wideband buffered analog amplifier having low output impedance of 200mOmega at high frequency. It can drive an RF PA with an equivalent impedance of 4Omega up to maximum output power of 2.25W with...
An integrated 5-output single-inductor multiple-output DC-DC converter with ordered power-distributive control in a 0.5mum BiCMOS process is presented. The converter has four main positive boost outputs programmable from +5 to +12V and one dependent negative output from -12 to -5V. A maximum efficiency of 80.8% is achieved at a total output power of 450mW, with a switching frequency of 700kHz.
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