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 Hybrid Magnetic Current Sensor With a Dual Differential DC Servo Loop

This article presents a hybrid magnetic current sensor for contactless current measurement. Pick-up coils and Hall plates are employed to sense the high and low-frequency fields, respectively, generated by a current-carrying conductor. Due to the differentiating characteristic of the pick-up coils, a flat frequency response can then be...

A Hybrid Magnetic Current Sensor With a Multiplexed Ripple-Reduction Loop

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 to 10 kHz) and high-frequency (10 kHz to 5 MHz) magnetic fields...

A 0.9-V 28-MHz Highly Digital CMOS Dual-RC Frequency Reference With ±200 ppm Inaccuracy From -40 °C to 85 °C

This article presents an energy-efficient dual- RC frequency reference intended for wireless sensor nodes. It consists of a digital frequency-locked loop (FLL) in which the frequency of a digitally controlled oscillator (DCO) is locked to a temperature-independent phase shift derived from two different RC poly-phase filters (PPFs). Phase...

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 CMOS-Imager-Pixel-Based Temperature Sensor for Dark Current Compensation

This brief proposes employing each of the classical 4 transistor (4T) pinned photodiode (PPD) CMOS image sensor (CIS) pixels, for both imaging and temperature measurement, intended for compensating the CISs' dark current, and dark signal non-uniformity (DSNU). The proposed temperature sensors rely on the thermal behavior of MOSFETs working in...

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 ± 12-A High-Side Current Sensor With 25 V Input CM Range and 0.35% Gain Error From −40 °C to 85 °C

This letter presents the most accurate shunt-based high-side current sensor ever reported. It achieves a 25 V input common-mode range from a single 1.8-V supply by using a beyond-the-rails ADC. A hybrid analog/digital temperature compensation scheme is proposed to simplify the circuit implementation while maintaining the state-of-the-art...

A Resistor-Based Temperature Sensor With a 0.13 pJ·K² Resolution FoM

This paper describes a high-resolution energy-efficient CMOS temperature sensor, intended for the temperature compensation of MEMS/quartz frequency references. The sensor is based on silicided poly-silicon thermistors, which are embedded in a Wien-bridge RC filter. When driven at a fixed frequency, the filter exhibits a temperature-dependent...

A ±4-A High-Side Current Sensor With 0.9% Gain Error From −40 °C to 85 °C Using an Analog Temperature Compensation Technique

This paper presents a fully integrated shunt-based current sensor that supports a 25-V input common-mode range while operating from a single 1.5-V supply. It uses a highvoltage beyond-the-rails ADC to directly digitize the voltage across an on-chip shunt resistor. To compensate for the shunt’s large temperature coefficient of resistance (∼0.335%...

A ±36-A Integrated Current-Sensing System with a 0.3% Gain Error and a 400-μA Offset From-55 °c to +85 °c

This paper presents an integrated shunt-based current-sensing system (CSS) capable of handling ±36-A currents, the highest ever reported. It also achieves a 0.3% gain error and a 400-μA offset, which is significantly better than the state-of-the-art systems. The heart of the system is a robust 260-μ Ω shunt resistor made from the lead frame...

A ±5A Integrated Current-Sensing System With ±0.3% Gain Error and 16 μA Offset From −55°C to +85°C

This paper presents an integrated current-sensing system (CSS) that is intended for the use in battery-powered devices. It consists of a 10 mΩ on-chip metal shunt resistor, a switched-capacitor (SC) ΔΣ ADC, and a dynamic bandgap reference (BGR) that provides the ADC's reference voltage and also senses the shunt's temperature. The CSS is realized...

A CMOS Temperature Compensated Log-Amp Detector

Publications of bipolar log-amp detectors for RF power detection show good temperature and RF performance. So far published CMOS log-amps fail to demonstrate accurate performance over temperature. This thesis present a temperature compensated CMOS RF power detector based on the log-amp architecture with an industry temperature range of -40 C to...

Mobility-based Time References for Wireless Sensor Networks

Wireless Sensor Networks require small low-cost radios to enable communication among its nodes. Since those radios must be fully integrated to reduce cost and size, integration is required also for their on-board time references, which are needed to achieve synchronization with the other nodes. To deal with the lower accuracy of integrated...