The IoT is unleashing an unimaginable number of connected devices, many of which are sensor systems that are designed to sense and interact with the world around them. The world around us is analog and analog sensors are often used to provide the sensing mechanism to the microcontroller. Analog circuits are often big, bulky and can add significant costs to a device. Using modern microcontrollers running digital signal processing (DSP) software, it’s possible to convert many analog circuits into equivalent software. There are five benefits to replacing analog components with DSP software.
Benefit #1 – Reduces BOM costs
The first, and most obvious benefit to converting an analog circuit into software is that the bill of material costs (BOM) decrease. The reason is that there are now fewer components per board that need to be purchased. In many cases, the reduction in materials is for components such as resistors and capacitors. Surface mount components can be inexpensive, on the order of a penny or less each, so it’s important to weigh the total cost savings over the life of a product to determine if it will be worthwhile. This can be done by taking the cost reduction per board, multiplying it by the volume per year and then multiplying by the number of years the product will be in production.
Benefit #2 – Increases design flexibility
It’s not uncommon when working with analog circuits and filters to have to constantly tune the circuits in order to get the best performance. A minor board re-spin can result in new electrical characteristics for the board that suddenly changes parasitic capacitance or inductance which results in a detuned analog circuit. Engineering teams then need to go and modify the analog circuits so that they work as expected again. Converting analog circuits into DSP algorithms not only removes this risk but also adds in the flexibility to tune and adjust the behavior as needed from software.
Benefit #3 – Decreases product dimensions
Decreasing the BOM cost has a fringe benefit that also allows developers to decrease the dimensions of their product. Fewer analog components, which can sometimes be bulky, means that the board size can be decreased. Decreasing the product dimensions has many cost related benefits to manufacturing such as:
- Saving on bare board costs per product
- Manufacturing more device per panel
- Spending less on plastics and housing materials over the product lifetime
These are all benefits that are often overlooked.
Benefit #4 – Cuts design cycle time
Converting analog circuits to software can help to decrease the design cycle time. There are several reasons why this is true. First, there are quite a few tools available that allow software designers to simulate and generate the DSP algorithms that they need to replace the analog circuitry. This is usually far faster than the time it takes to tune a circuit through circuit simulation and bench testing. Second, if changes need to be made, they can be made in the software which can be done in minutes versus having to re-spin boards or make hardware modifications.
Benefit #5 – In-field adaptability
In some products, you never know what conditions will be encountered in the field by the end users. Using DSP algorithms allow a team and even the end user to make on-the-fly adjustments to adapt to conditions in the field without having to make a bunch of hardware modifications. Field adaptability can even simplify the supply chain and manufacturing process by removing the number of sku’s that need to be built to meet various customer’s needs.
Conclusions
As we have seen in this post, there are many benefits to replacing analog circuits with digital signal processing algorithms. It’s important that a development team learn how to evaluate whether they should use an analog circuit or DSP software. The decision may require carefully weighing the benefits and benefit costs to make sure that they will outweigh the additional cost and complexity of the software. If the scale tips towards the DSP software, then the replacing analog components makes a lot of sense.
If you are interested in learning more about how to choose between analog circuits and DSP software, attend the free webinar “How to Choose: Analog Hardware or Digital Signal Processing Software” which will be streamed live on January 24th, 2019 and will be available on-demand afterwards.
