A 0.01 mm²10MHz RC Frequency Reference with a 1-Point On-Chip-Trimmed Inaccuracy of ±0.28% from -45°C to 125°C in 0.18μm CMOS

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 compensation to achieve decent accuracy. Enabled by high-resolution...

A Compact 10-MHz RC Frequency Reference With a Versatile Temperature Compensation Scheme

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. Conventionally, an RC time constant with a near-zero temperature coefficient...

A 13.56MHz Fully Integrated 91.8% Efficiency Single-Stage Dual-Output Regulating Voltage Doubler for Biomedical Wireless Power Transfer

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, the conventional dual-output structure suffers from a low voltage...

31.3 A 0.14mm²16MHz CMOS RC Frequency Reference with a 1-Point Trimmed Inaccuracy of ±400ppm from -45°C to 85°C

Recently, rapid strides have been made in improving the accuracy of RC-based frequency references [1 -3]. Inaccuracies better than \pm 500ppm from -45^{\circ}C to 85^{\circ}C have been achieved, but typically at the expense of a costly and time-consuming 2-point trim to compensate for RC spread and temperature dependence. This paper describes...

An Energy-Efficient 3.7-nV/√ Hz Bridge Readout IC With a Stable Bridge Offset Compensation Scheme

This paper describes an energy-efficient bridge readout IC (ROIC), which consists of a capacitively coupled instrumentation amplifier (CCIA) that drives a continuous-time delta–sigma modulator (CTM). By exploiting the CCIA’s ability<br/>to block dc common-mode voltages, the bridge’s bias voltage may exceed the ROIC’s supply voltage, allowing...

A 15-nW per Sensor Interference-Immune Readout IC for Capacitive Touch Sensors

This paper presents a readout IC that uses an asynchronous capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. A power-efficient tracking algorithm ensures that the CDC consumes negligible power consumption in the absence of touch events. To facilitate its use in wake-on-touch applications, the CDC can be...

A 15nW per Button Noise-Immune Readout IC for Capacitive Touch Sensor

This paper presents a readout IC that uses an asynchronous charge-redistribution-based capacitance-to-digital-converter (CDC) to digitize the capacitance of a touch sensor. Thanks to the power efficient tracking algorithm, the CDC consumes negligible power consumption in the absence of touch events. To facilitate stand-alone or wake-on-touch...

Energy-Efficient Bridge-to-Digital Converters

This paper presents an overview of energy-efficient analog-to-digital converters (ADCs) specifically intended for the readout of Wheatstone bridge sensors. Apart from achieving good energy-efficiency, such bridge-to-digital converters (BDCs) must achieve low input-referred offset, drift and noise; high gain accuracy, stability and linearity;...

A 4.5 nV/√Hz Capacitively Coupled Continuous-Time Sigma-Delta Modulator with an Energy-Efficient Chopping Scheme

When chopping is applied to a continuous-time sigmadelta modulator (CTΣΔM), quantization noise fold-back often occurs, leading to increased in-band noise. This can be prevented by employing a return-to-zero (RZ) digital-to-analog converter (RZ DAC) in the modulator's feedback path and arranging the chopping transitions to coincide with its RZ...

A Hybrid Multi-Path CMOS Magnetic Sensor with 76 ppm/°C Sensitivity Drift and Discrete-Time Ripple Reduction Loops

This paper presents a temperature-insensitive magnetic sensor system for contactless current measurements. To simultaneously achieve wide bandwidth and low noise, the proposed system employs a multi-path structure with a set of spinning current Hall sensors in its low-frequency path and a set of pick-up coils in its high-frequency path. The...

Multipath Wide-Bandwidth CMOS Magnetic Sensors

This paper proposes a multipath multisensor architecture for CMOS magnetic sensors, which effectively extends their bandwidth without compromising either their offset or resolution. Two designs utilizing the proposed architecture were fabricated in a 0.18-μm standard CMOS process. In the first, the combination of spinning-current Hall sensors...

A CMOS Temperature Sensor with a 49fJ·K2 Resolution FoM

This paper presents the most energy-efficient CMOS temperature sensor ever reported, with a resolution FoM of 49fJ·K2, 2.7× better than the state-of-the-art. It consists of a Wheatstone bridge made from poly-silicon resistors, which is readout by a 2nd-order Continuous-Time Delta-Sigma modulator (CTDSM). This approach leads to a high resolution ...

A Continuous-Time Ripple Reduction Technique for Spinning-Current Hall sensors

This paper presents a new ripple-reduction technique for spinning-current Hall sensors, which obviates the need for lowpass filtering to suppress the ripple caused by up-modulated sensor offset. A continuous-time ripple-free output is achieved by the use of three ripple reduction loops (RRLs), which continuously sense the offset ripple and then...