The importance of programmable technology in a smarter digital age

As the Internet of Things (IoT) continues to grow, the interconnectivity of countless wireless devices has ushered in unprecedented levels of automation and data exchange. However, at the front-end of this gigantic interconnected network, data acquisition sensors are facing a new set of challenges. Weak signals, complicated environmental interference, and the wide range of performance requirements across various applications make it hard for conventional sensing technology to keep up with the demands of today’s IoT. At the same time, the embedded systems at the core that drive the majority of these devices, such as MCUs, must comply with rigorous size, cost, and power consumption requirements.

Fortunately, the emergence of programmable technology has helped smart sensors and embedded systems overcome many of these challenges. This technology enables flexible designs that can enhance or adjust the signal processing power of sensors, while also ensuring the majority of devices run smoothly and efficiently under all kinds of conditions. It also helps embedded systems to better balance functionality, power consumption, and cost.

“Volume buttons” for sensors: unlocking the magic behind programmable-gain amplifiers (PGA)

Sensors are an integral part of daily life. They are a dedicated task force that is constantly monitoring changes in our environment, operating machinery, and even our vital signs. But the signals produced by these sensors are relatively weak, and can be easily affected by interference. Thanks to programmable technology, special solutions like programmable-gain amplifiers (PGA) and programmable gain instrumentation amplifiers (PGIA) can enhance these signals and protect them from interference.

Imagine these sensors as speakers with adjustable volumes. PGA and PGIA are like the knobs that can turn the volume of the signals up or down, so that the devices to which they are linked, such as medical devices, smart phones and cars, can better receive and analyze them. Essentially, the programmable gain controls in the amplifiers automatically adjust themselves according to the requirements of different application scenarios.

What makes them unique?

• Accuracy: PGA or PGIA can accurately control the amplification level of signals. This is especially important for applications that require high precision, such as medical settings or precision measurements.
   
• Flexibility: A programmable design allows for simple adjustments to be made, based on the requirements and conditions, without having to change hardware or make complex manual adjustments.
   
• Integration: These amplifiers are typically integrated into a single chip. This saves valuable space while also providing more reliable performance.

Master volume: how to optimize PGA/PGIA performance

There are several key factors that designers need to consider when deciding whether to use PGA or PGIA. The first is response time. The signal will need time to stabilize once the amplifiers have changed their amplification settings. This is particularly important for rapidly changing signals and high-speed scanning systems. 

Secondly, accuracy and stability are of vital importance. These amplifiers must be capable of providing accurate and stable performance within the full range of their working temperatures. 

Thirdly, designers must be aware of potential causes of interference and errors, such as mild capacitance or resistance in the circuit.

Integrated single chip amplifier solutions like the Microchip MCP6G01 SGA, or ISL28533 from RISA, can largely solve these issues and overcome design challenges. Careful coordination between the proper tolerance for design elements and reliable temperature can further improve performance. In addition, gain selection logic helps to simplify the control of the host system, while also reducing the bill of materials (BOM) and saving PCB space. Designers must also consider other additional performance indicators like gain propagation delay and power consumption. If designers are unable to find an appropriate single chip device, their choice of analog components can have a significant impact on the performance of the wireless devices.

 
The block diagram for MCP6G01 by Microchip shows the gain selection logic used in the product. (Source: Microchip)

Programmable analog technology: redefining the future of embedded systems

Besides sensors, embedded systems are used to control almost all the devices we use every day, from smart phones to industrial automation systems. Embedded systems are responsible for processing and responding to complex data records; they are the heart of modern electronic devices.

Embedded systems are often the link between the analog and digital worlds. These interfaces are usually created using an analog front end (AFE). Traditionally, various discrete analog components and IC components, such as operational amplifiers and data converters, are used to construct the circuits. This conventional approach, however, is subject to space, cost, and power consumption constraints. Though technological advances have led to integrated analog microcontroller units (MCUs) providing a more efficient solution, functionality and flexibility are still limited.

Increasing demand for growth, coupled with increasingly complex wireless devices, led to the creation of programmable analog integrated circuits. The programmable design allows for the most complete set of analog peripherals with an integrated analog MCU. Hence engineers can configure a range of analog functions on a single chip, while maintaining balanced functionality that supports continual development.

Designing a programmable analog integrated circuit is still no easy task. These integrated circuits have to provide all the necessary analog signal chain functions. These functions can vary widely, depending on whether they’re used in sensor interfaces, data converters, and so on. Compared to MCUs, which offer limited integration of analog peripherals, programmable analog devices must be able to support multiple input and output channels. Hence new design techniques are necessary to achieve successful configuration.

The PSoCTM series from Infineon Technologies uses a pioneering technology that combines a microcontroller with programmable analog and digital modules. This allows programmers to enjoy an unprecedented level of flexibility, and marks an important milestone for the world of engineering. These methods not only reduce cost and complexity for the BOM, but also reduce the dimensions of circuit boards, while providing reconfiguration in real time. This would never have been possible in a conventional integrated MCU.
 

How exactly does Infineon’s programmable analog device work? The underlying framework behind the PSoCTM device is a switch capacitor analog module. The device is able to simulate the behavior of a resistor, an amplifier, and other conventional analog elements, by accurately controlling the charging or discharging of the capacitor. The advantage of this technology is that it allows accurate control of the analog circuit at the microscopic level, while occupying less physical space.

Like Infineon, Renesas has also developed its own solution. Its GreenPak programmable hybrid signal device also uses switch capacitor technology. Unlike the Infineon solution, the Renesas GreenPAK series is an alternative solution that does not use an MCU. Engineers are still able to integrate all kinds of analog and digital functions but will not require the processing power of a microcontroller. The GreenPAK solution also does a good job in reducing the cost and the number of elements for the BOM, all while saving space on the circuit board.

Despite their similarities, the respective programmable analog solutions of Infineon and Renesas are implemented and used in different ways. Infineon’s PSoCTM is geared toward applications that require a highly integrated MCU, while GreenPak provides broader hybrid signal support functions without an MCU core.

Conclusion

Programmable technologies like PGA and programmable IC offer significant competitive advantages that will play an increasingly important role in the digital age. As programmable technology continues to improve, more and more accurate data will become readily available to meet the increasing demands of various industries. And, as sensors become more reliable, the world will become smarter and smarter, and safer and safer.