A Thermoelectric Energy Harvesting System Assisted by A Piezoelectric Transducer Achieving 10-mV Cold-Startup and 82.7% Peak Efficiency

This article presents a 10mV-startup-voltage thermoelectric energy harvesting system, assisted by a piezoelectric generator (PEG) as a cold starter. It exploits the fact that when a thermoelectric energy harvesting system is implemented in a place where kinetic energy is also present, the PEG starter can provide a clock signal to start the...

A Sub-1 V Capacitively Biased BJT-Based Temperature Sensor With an Inaccuracy of ± 0.15 ∘ C (3 σ ) From − 55 ∘ C to 125 ∘ C

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 precharging sampling capacitors to the supply voltage and then discharging...

A Single-Stage Three-Mode Reconfigurable Regulating Rectifier for Wireless Power Transfer

In this article, we propose a reconfigurable regulating rectifier with a wide operational range for wireless power transfer. The proposed three-mode rectifier achieves a broad range voltage regulation without global loop control to minimize the chip area occupation. Compared with previous work, more working modes and greater voltage gain...

30.3 A Bias-Flip Rectifier with a Duty-Cycle-Based MPPT Algorithm for Piezoelectric Energy Harvesting with 98% Peak MPPT Efficiency and 738% Energy-Extraction Enhancement

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 maintenance cost. However, the output power extracted by such rectifiers...

23.7 A BJT-Based Temperature Sensor with ±0.1 C(3σ) Inaccuracy from -55°C to 125°C and a 0.85pJ.K²Resolution FoM Using Continuous-Time Readout

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 thermal-diffusivity based sensors achieve superior accuracy at...

23.2 A 40 A Shunt-Based Current Sensor with ±0.2% Gain Error from -40°C to 125°C and Self-Calibration

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 exhibit increased drift, especially at high current levels. This...

23.5 A Sub-1V 810nW Capacitively-Biased BJT-Based Temperature Sensor with an Inaccuracy of ±0.15°C (3σ) from -55°C to 125°C

BJT-based temperature sensors are widely used because they can achieve excellent accuracy after 1-point calibration. However, they typically dissipate mu textWs of power and require supply voltages above 1V [1]. Although sensors based on DTMOSTs [2], [3], capacitively biased (CB) diodes and BJTs [4,5] have demonstrated sub-1V operation, this...

A ±25A Versatile Shunt-Based Current Sensor with 10kHz Bandwidth and ±0.25% Gain Error from -40°C to 85°C Using 2-Current Calibration

Accurate current sensing is critical in many industrial applications, such as battery management and motor control. Precise shunt-based current sensors have been reported with gain errors of less than 1% over the industrial temperature range (-40°C to 85°C) [1]–[4]. However, since they are intended for coulomb counting, their bandwidth is...

A Versatile ± 25-A Shunt-Based Current Sensor With ± 0.25% Gain Error From − 40 ∘ C to 85 ∘ C

This article presents a versatile shunt-based current sensor for battery management applications. It digitizes the current-induced voltage drop across an external shunt resistor with the help of a 2 nd -order delta-sigma ( ΔΣ ) ADC, whose summing node is implemented as a low-noise capacitively coupled amplifier. To compensate for the shunt’s...

A 0.96-mW dB-Linear Variable Gain Amplifier With 0.4-dB Linearity Error Over a 62.4-dB Gain Tuning Range

This letter presents a low-power dB-linear variable gain amplifier (VGA) with a small linear-in-dB error over a wide gain tuning range. An exponential current ratio is realized in the linear-in-dB control circuit based on the subthreshold I-V characteristic. The VGA is built with subthreshold common-gate transistors as current steering,...

An energy-efficient capacitively biased diode-based temperature sensor in 55-nm CMOS

This work presents an energy-efficient diode-based CMOS temperature sensor. It is based on the capacitively biased diode (CBD) working principle and can operate with a 1-V supply voltage. Instead of using a separate CBD front-end and ADC, a new architecture is proposed in which the CBD front-end is directly embedded into the 1st stage of a 1...

A BJT-Based CMOS Temperature Sensor with Duty-Cycle-Modulated Output and ±0.5°C (3σ) Inaccuracy from -40 °c to 125 °c

This brief presents a 0.65% relative inaccuracy CMOS temperature sensor with a duty-cycle-modulated (DCM) output. It uses a BJT-based front-end to generate a proportional to absolute temperature voltage (V_{PTAT}) and a complementary to absolute temperature voltage (V_{CTAT}), which are then modulated to a digital-friendly duty-cycle output....

Iterative equalization for OFDM systems over wideband Multi-Scale Multi-Lag channels

OFDM suffers from inter-carrier interference (ICI) when the channel is time varying. This article seeks to quantify the amount of interference resulting from wideband OFDM channels, which are assumed to follow the multi-scale multi-lag (MSML) model. The MSML channel model results in full channel matrices both in the frequency and time domains....

Identifying time-varying channels with aid of pilots for MIMO-OFDM

In this paper, we consider pilot-aided channel estimation for orthogonal frequency division multiplexing (OFDM) systems with a multiple-input multiple-output setup. The channel is time varying due to Doppler effects and can be approximated by an oversampled complex exponential basis expansion model. We use a best linear unbiased estimator (BLUE)...

A Novel Receiver Architecture for Single-Carrier Transmission over Time-Varying Channels

In this paper, we present a single-carrier transceiver for rapidly time-varying channels, where the equalization step is implemented in the frequency domain. When the channel abides with both fast fading and severe inter-block interference, our equalizer relies on a band approximation of the frequencydomain channel matrix to maintain low...

OFDM transmissions over rapidly changing channels

This thesis is dedicated to efficiently estimate and equalize time-varying channels in OFDM and single-carrier systems.