Tag Archives: STMicroelectronics

App note: USB hardware and PCB guidelines using STM32 MCUs

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Peripheral USB on STM32 MCUs app note from STMicroelectronics. Link here (PDF)

STM32 microcontrollers include a group of products embedding a USB (Universal Serial Bus) peripheral. Full-speed and high-speed operations are provided through embedded and/or external PHYs (physical layers of the open system interconnection model).

This application note gives an overview of the USB peripherals implemented on STM32 MCUs, and provides hardware guidelines for PCB design, to ensure electrical compliance with the USB standards.

App note: USB Type-C™ power delivery using STM32xx series MCUs and STM32xxx series MPUs

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Guideline from STMicroelectronics on the basics of the two new USB Type-C™ and USB Power-Delivery standards. Link here (PDF)

This new reversible USB Type-C™ connector makes plug insertion more user friendly. The technology offers a single platform connector carrying all the necessary data. Using the power delivery protocol, it allows negotiation of up to 100 W power delivery to supply or charge equipment connected to a USB port, the objective being fewer cables and connectors, as well as universal chargers.

The USB Type-C™ connector provides native support of up to 15 W (5 V @ 3 A), extendable to 100 W (up to 20 V @ 5 A) with the optional USB Power Delivery feature.

App note: How to implement an SCR or a Triac in hybrid relay applications

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Another app note from STMicroelectronics on SCR or Triac hybrid with mechanical relay to decrease power loss and manage inrush current. Link here (PDF)

This document gives some key information about the design of the solid-state silicon AC switch stage of a hybrid relay, which can drive resistive, capacitive or inductive AC loads, such as: heater resistors, motors for industry, power tools or appliance applications.

App note: AC switches – Is a positive power supply mandatory for my application, or could a negative output work also?

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App note from STMicroelectronics about the usage of a negative supply in controlling AC switches and their benefits, Link here (PDF)

In this application note we explain the reasons why some appliance designers might choose a positive power supply. This selection is based mainly on the choice of switched mode power supply (SMPS). Some specific applications cases, may also lead to the choice of a positive power supply.

Using a power supply with a positive output is not convenient for all applications. For example, a negative supply is preferred to drive AC switches. We provide here an alternative solution which allows a negative output to be implemented whenever possible. Further, many solutions allow both a negative and a positive output (for the microcontroller) to be implemented.

App note: Current sharing in parallel diodes

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Application note from STMicroelectronics on the performance of each diode in a parallel diode connection and how the forward voltage dispersion can have a great impact over thermal effect on the current imbalance. Link here (PDF)

The use of diodes in parallel is commonly found in power electronic design. An important consideration for this practice is the current sharing between diodes due to the difference of electrical characteristics. This application note highlights the cause of the behavior of several diodes are connected in parallel. Some recommendations will be given to help the designer to produce a safe design. An electro-thermal model is described which simulates the current and junction temperature of each diode for given application conditions. This tool is illustrated using an example.