Universal Serial Bus (USB) is truly a success story in many applications. Do you remember its introduction in 1996? Originally, USB just had four pins (USB A), a 5 V supply, and a differential pair to transmit data at 12 Mbps. Since then, the technology has advanced significantly—introducing Mini-USB, Micro-USB, and now USB Type-C at an impressive 20 Gbps. Even video transmission is possible. Interestingly, EU legislation mandating one universal power supply for all portable devices led to greater accessibility and usability between various manufacturers’ products worldwide—while significantly reducing electronic waste. Nowadays, a USB charger with USB-PD technology can now power a device using up to 240 W. The successful evolution of USB technology since its introduction serves as an example of how smart policy can lead to innovations that aid sustainability.
Let’s take a look at the first Analog Dialogue article:
Commercial buildings and sports venues require quality cellular coverage, but these environments pose signal reception challenges. The article “Revolutionizing Wireless Coverage: The Power of Cellular DAS Integrated Solutions” presents a comprehensive solution for distributed antenna systems (DAS), which are essential for extending cellular coverage and capacity within building structures. It will outline the benefits of highly integrated system designs that include an RF transceiver coupled with a bidirectional amplifier (BDA) or remote access unit (RAU) equipment. By exploring this solution through the proposed block diagrams, readers can better understand how these elements work together.
The next article is “Simplify Your USB-C PD Design Using a Standalone PD Controller.” USB Power Delivery (PD) is continuing to transform portable, battery-operated electronic devices like cell phones, laptops, wireless speakers, power tools, and much more. USB PD provides a great benefit to consumers because it can provide up to 240 W of power via a single USB Type-C connector. This article shows how the assimilation of 5 V, 9 V, 15 V, 20 V, 28 V, 36 V, and 48 V voltage rails provides versatility in power delivery.
The following article, “Step-by-Step Process to Calculate a DC-to-DC Compensation Network,” aims to assist designers with an understanding of how DC-to-DC compensation works, why the compensation network is needed, and how one can easily achieve effective results with the right tools. The method used for verifying the calculation of the compensation network involves a simple LTspice® circuit that is based on a first-order (linear) model of a current-mode buck converter. Verifying compensation network values can be done more easily without having to perform complex mathematical calculations.
In this month’s RAQ, “Generating Negative Voltages—Why You Need Level Shifting in Buck-Boost Circuits,” we explain why level shifting is necessary and what to consider when designing level shift circuits. Inverting buck-boost circuits are commonly used for generating negative supply voltages from positive voltages. The most important step is ensuring that the negative voltages are generated correctly. However, additional level shifting circuits may be required if the power supply is controlled or supervised by the main application circuit.
Our StudentZone article, “ADALM2000 Activity: Heartbeat Measurement Circuit,” explains how to use a chain of amplifiers for gain and filtering by exploring the fascinating design behind a fingertip heartbeat detection device. This type of optical device monitors heartbeat by measuring light absorption as blood is pumped through the finger. A pair of infrared (IR) LEDs is used in combination with a phototransistor. The LEDs emit light through the finger which is then detected by the phototransistor, which acts like a variable resistor conducting different amounts of current depending on the light received. This article explains how to drive an IR LED and a phototransistor and aims to provide an understanding of the behavior of a low-pass filter and the functions provided by the operational amplifiers.
And as we have for over 56 years, we invite you to be part of the dialogue in Analog Dialogue. You can get in touch through our blog, Facebook page, or email. Let us know how we’re doing and what you’d like to see from us in the coming months.