Sensor Interface - Analogue Front End Family "From the Real World to the Digital Word"

Introduction

The vast majority of electronic devices today use the sensors to detect some physical phenomenon in the world that surrounds us (like temperature, pressure, light intensity, etc). The sensors transpose the events from the physical world into electrical signals suitable for further processing, which ultimately ends by providing useful information to the user. The conditioning and processing of the electrical signal from the sensor is a crucial part, since these signals can be quite small and can be easily corrupted due to today’s environment with many sources of the interferences (electronic devices, cars, mobile phones, etc).

The signal processing is done in the form of integrated circuit (chip) that has many benefits: small size, high reliability, low consumption (battery powered devices), low production cost for the series production, etc. The processing ends with the data conversion to the digital form utilized by standard controlling units: microcontrollers, found in smaller electronic systems, also known as the "embedded systems", then microprocessors, found in the mobile devices, laptops and PCs, and similar digital devices.

Systemcom Ltd. launched the family of chip solutions which can be used for instance with light sensor, to capture light, then to process the information and provide data to the standard controlling unit (electronic device). The product line consists of silicon proven, so called IP ("Intellectual Property") modules, as the components of the sensor interface - Analogue Front End (AFE) family. It can be really said that such chip solutions make connection from the real world to the digital word.

From the Real World to the Digital Word

Systemcom’s know-how is not only limited to the chip design and testing but also incorporates software development in the area of supporting hardware design activities (Electronic Design Automation - EDA) as well as in embedded and dedicated software applications.

Sensor Interface - Analogue Front End Family

Sensor interface - Analogue Front End family provides the programmable analogue front-end function, optimized for the current-input, low power and high resolution applications. The respective IP modules provide a complete signal path between sensor system and suitable analogue-to-digital converter. They are ideally suited for a broad range of devices with the sensor system where the generic information about the phenomenon to be measured (light or other physical, chemical and electrochemical appearances) passes the first electrical conversion to the current. The IP modules allow current measurement in the wide range (hundreds of pA to 1 mA) as well as the measurement of small current differences (tens of pA). The IP implementation enables easy further System on Chip (SoC) integration of the follow up functions. The IP modules are silicon validated in TSMC 180nm CMOS analogue/mixed signal technology.

Attractiveness

The main advantages of Systemcom’s solution are robustness and flexibility in a way of detecting and processing various ranges of the input current within the same working conditions (regulated sensor voltage, 12-bit resolution for output voltage swing). The current to voltage conversion features high linearity. Further signal processing features programmable gain up to 1300 providing differential voltage at its output.

Beside the robustness and flexibility there are other very important benefits that are worth to point. The chips are designed to operate at the temperatures from -40°C to 125°C that is way above the industrial temperature range. They also have very good noise characteristics and the interference immunity. With such functionality achieved, Systemcom is free to state "we developed low power, low noise and high precision IP modules that can stand side by side with the products of recognized companies in analogue/mixed integrated signal circuits field".

Potentials

The AFE family has modular architecture, so that it is suitable to customize it in a rather short time. The minor additions, i.e. application targeted customization, are as follows: customizable current ranges (like high current detection up to 10 mA for the industrial applications), rearrangement of the PGA (Programmable Gain Amplifier) gain, adjustment of AFE's output to match required ADC input, ability to upgrade into multi-channel input, possibility to detect input voltages instead of input currents or both, etc.

Systemcom is also launching extended AFE family based on the core IP module with additional features like ADC and wire interface (SPI). Respective IP modules are also suitable for the implementation in Application Specific Integrated Circuit (ASIC) and/or Application Specific Standard Product (ASSP).

Customization Potentials

Applications and Market

The application field of the sensor interface AFE family is large i.e. wherever the electronic device has the sensor with the current output, the AFE IP module is welcome as the interface to the digital signal processing unit, like an embedded system. It is ideally suited for photo sensing. The input current range achieved with those IP modules is very usable in the biomedical equipment, especially non-invasive one, where optical and electrochemical sensors are mostly used. Just to mention some applications: DNA analysis, heart rate monitor, blood analysis devices, xray detection, pyrometers, CT scanners, chromatography, etc.

The sensor interface AFE family, including also above mentioned customizations, has huge market potential. The most attractive applications with high growing market are as follows:

• smartphones, gadgets, PCs and notebooks with built-in sensors like: accelerometer, gyroscope, pressure (+ altitude detection), temperature, gases, humidity, light, ultra-violet, proximity; then more specific like: smoke-alarm, air quality, radiation, glucose, alcoholdetector, etc.
• energy saving & control equipment like smart meters and smart grids (electricity, water, heat, gas), solar panels management, etc.
• environmental industry (agriculture, aquaculture, food, ecology with soil, air, water pollution monitoring)
• medical equipment and biomedical industry (various types of battery powered "home use" devices with low power requirement), telemedicine, health care
• process control and automotive industry (proximity sensors, rain sensors, light sensors, etc.)

Electronic set-up example for the typical application is shown in the figure below.

Application Example

Systemcom’s sensor interface AFE family enhances the overall offer in the field of analogue front end integrated circuits, especially because of sophisticated solution with current input. All in all, the world is analogue!

About Systemcom Ltd.

Founded in 1993, Systemcom Ltd. is a privately owned fabless design house located in Zagreb, Croatia. It supplies IC design service, IP modules and ASICs for worldwide customer base, not only for sensor applications, but also for other high performance analogue, mixed signal and digital ICs. The expertise in microelectronics and SW development has been achieved in the long-time collaboration with Bosch, Intel, HP & Compaq (Alpha) for more than ten years. The company is dedicated to support customers in achieving shortest time cycle from the product concept to the revenue shipment.