KM
K.A.A. Makinwa
368 records found
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A single-stage dual-output regulating voltage doubler (DOVD) is proposed for biomedical wireless power transfer (WPT) systems. Derived from the full-wave voltage doubler (VD) topology, it achieves ac-to-dc rectification and dual-output voltage regulation in a single stage by usin
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This article describes a PNP-based temperature sensor that achieves both high energy efficiency and accuracy. Two resistors convert the CTAT and PTAT voltages generated by a PNP-based front-end into two currents whose ratio is then digitized by a continuous-time (CT) Δ Σ -modulat
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This paper presents a direct conversion transceiver intended for use in a microfluidic NMR flowmeter. It consists of an H-bridge power amplifier, which drives a hand-wound milimeter-sized coil with RF signals, and a direct conversion receiver, which amplifies the NMR signals pick
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Advances in CMOS technologies and circuit techniques have led to the development of continuous-time delta-sigma modulators (CTΔ Σ Ms) that sample at gigahertz (GHz) frequencies and achieve high linearity [-100 dBc and >120 dBFS spurious-free dynamic ranges (SFDRs)] in wide ban
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This article presents a CMOS temperature sensor that achieves both state-of-the-art energy efficiency and accuracy. An NPN-based front end uses two resistors to efficiently generate a PTAT and CTAT current, whose ratio is then digitized by a continuous-time (CT) Δ Σ -modulator. A
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Bias-flip rectifiers are commonly employed for piezoelectric energy harvesting (PEH). This article proposes a synchronized switch harvesting on an inductor (SSHI) rectifier with a duty-cycle-based (DCB) maximum power point tracking (MPPT) algorithm. The proposed DCB MPPT algorith
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Advances in CMOS technologies have led to the development of continuous-time ΔΣ modulators (CTDSMs) with GHz sampling rates that achieve better than-100dBc linearity and bandwidths above 100MHz. However, at low frequencies (below 10MHz), their SNDR is limited by 1/f noise, which
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Dual-output regulating rectifier is highly desired in wireless power transfer (WPT) for sub-100mW bioimplants. Such rectifiers perform voltage rectification and dual-output regulation simultaneously, thus avoiding post DC-DC conversions and cascaded power losses [1 –4]. However,
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This paper presents a nano-power high-side shunt-based current sensor (CS) that digitizes the voltage drop across an on-chip (±1A) or a lead-frame (±30A) shunt. A TC-tunable ADC reference compensates for the shunts' large temperature coefficient (TC), resulting in ±0.5% gain erro
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BJT-based temperature sensors are widely used due to their high accuracy over a wide temperature range with a low-cost 1-point trim. Although resistor-based sensors can achieve better energy efficiency, they typically require a 2-point trim to achieve comparable accuracy, while t
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Synchronized bias-flip rectifiers, such as synchronized switch harvesting on inductor (SSHI) rectifiers, are widely used for piezoelectric energy harvesting (PEH) [1], which can replace the use of batteries in many loT applications, thus reducing both system volume and maintenanc
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In chopper amplifiers, the interaction between the input signal and the chopper clock can cause intermodulation distortion (IMD). This is mainly due to finite amplifier bandwidth, which causes signal-dependent output spikes at the chopping transitions. Such chopper-induced IMD ca
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This article presents a hybrid magnetic current sensor for galvanically isolated measurements. It consists of a CMOS chip that senses the magnetic field generated by current flowing through a lead-frame-based current rail. Hall plates and coils are used to sense low-frequency (dc
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This article presents a sub-1 V bipolar junction transistor (BJT)-based
temperature sensor that achieves both high accuracy and high energy
efficiency. To avoid the extra headroom required by conventional current
sources, the sensor’s diode-connected BJTs are biased by prechar
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This article presents a digital-input class-D amplifier (CDA) achieving high dynamic range (DR) by employing a chopped capacitive feedback network and a capacitive digital-to-analog converter (DAC). Compared with conventional resistive-feedback CDAs driven by resistive or current
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CMOS frequency references based on RC oscillators are usually preferred over bulky crystals in loT applications [1-5]. However, due to the process spread and finite temperature coefficient (TC) of most on-chip resistors, RC oscillators require trimming and temperature compensatio
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This article presents the design and implementation of a compact CMOS RC frequency reference. It consists of a frequency-locked loop (FLL) that locks the period of a voltage-controlled oscillator (VCO) to the time an RC network takes to charge to a reference voltage. Conventional
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Low-cost metal (e.g., PCB trace) shunts can be used to make accurate current sensors (< 1 % gain error) [1-3]. However, their reported maximum operating temperature (85 circC) is not high enough for automotive applications, and at higher temperatures, shunt resistance may exhi
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Quantifying Biomedical Amplifier Efficiency
The noise efficiency factor
There has been a long-standing interest in controlling and instrumenting the human body. Whether to restore lost function with neural prosthetics, monitor blood glucose levels, or augment human capabilities, there are countless opportunities for sensors inside ( e.g., ingestible,
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Class-D amplifiers (CDAs) are widely used in audio applications where a high power efficiency is required. As most audio sources are digital nowadays, implementing digital-input CDAs results in higher levels of integration and lower cost. However, prior open-loop digital-input CD
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