Simulation-driven virtual prototyping is employed in the design of modern smart products to accelerate product development speed, ensure intrinsic product qualities and improve the decision-making process during development. It results in smart products that are more cost-effective with higher quality and reliability. This is shortened version of the article for print - here is a link to the extended version https://www.microwavejournal.com/articles/36379-simulation-driven-virtual-prototyping-of-smart-products-full-article.
Figure 1 Smart speaker components.
Over the past few decades, the wireless industry has experienced tremendous innovation and transformation, driven by the introduction of wireless communication standards such as 4G LTE, 5G, Bluetooth (BT) and Wi-Fi.1 This, coupled with new rapid manufacturing techniques, requires advanced product design with complex multiphysics considerations. Competition in the consumer electronics market calls for designs that improve product performance while lowering development costs and reducing time to market. These challenges can be addressed by simulation-driven virtual prototyping to reduce physical testing.2-4 Moreover, simulation-driven virtual prototyping can be employed in the design of modern smart products to accelerate product development speed, ensure intrinsic product qualities and improve the decision-making process during development. Simulation-driven design is important for ensuring the completeness and timely market launch of smart products.
For example, Figure 1 shows the product development process for a smart speaker assembly comprising a speaker component, printed circuit board (PCB), assembled electrical components and cabinet. A three-step simulation-driven virtual prototyping methodology was used in its development: 1) the design, verification and analysis of the PCB; 2) the design and integration of the BT antenna on the PCB inside the speaker cabinet; 3) a wireless communication performance evaluation of the smart speaker considering a neighboring wireless product.
PCB DESIGN
Figure 2 Assembled PCB top (a) and bottom (b) views.
The current generation of smart speakers receives audio signals wirelessly. One of the most popular RF standards supporting audio transmission to speakers is BT. A smart speaker includes a mostly BT wireless section, charging circuitry, audio amplifier for quality audio output, user display and the main controller with memory that provides a reliable connection with the functional blocks. For a high-quality smart speaker, aspects such as audio signal quality, BT antenna performance and interference with other wireless signals must be considered.
Figure 2 shows the six-layer PCB with its electronic circuitry, which measures 106 × 137 × 0.7 mm thick. The board contains the audio amplifier; memory for storing wireless information such as pairing details, battery status and smart applications; USB connectivity for charging or diagnosing; charging and power supply circuitry; BT IC and antenna for wireless connectivity; and an LCD driver and display module. A microcontroller synchronizes the functionality of all the parts.
Although the ICs that define operational functionality are important, equally important are the other parts ensuring system reliability. The differential nets in audio lines, connectivity between the controller and the memory IC (i.e., the clock, address, command and data lines), differential data lines from the USB to the controller and the antenna for the BT module are crucial for meeting the quality and efficiency requirements.
VERIFICATION AND ANALYSIS
Figure 3 PCB layout to be verified and analyzed.
Layout of the audio, USB and memory lines must be carefully designed for reliable operation, using verification and analysis methods to ensure design integrity. Figure 3 shows the target layouts for verification and analysis of the differential audio and high speed lines (i.e., the USB interface and memory bus). To verify the differential audio line layout, a rule-based checker, Altair’s PollEx PCB Verification for Design for Electrical Engineering, was used.5 Signal integrity (SI) analysis was conducted to evaluate the layout of the high speed lines and the effects on transmitting and receiving digital signal waveforms and voltage/time margins. In addition to SI analysis, the thermal characteristics of the PCB were analyzed. Thermal analysis early in the design stage can identify excessive component temperatures and uneven board temperature.
