App note: Passive entry door system with proximity sensor

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A full implementation of a keyless entry from Microchip. Link here (PDF)

The door access systems have evolved from simple physical keys to more sophisticated keyless entry systems. Now, we have a system that automatically unlocks the door when user carrying an access key approaches the door handle. As it does not require any user action this system is referred to as Passive Entry

App note: Low Power POE Flyback Converter

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App note from Microchip about their MIC2145 boost switching regulator to do POE Flayback conversion. Link here (PDF)

The MIC2145 skip mode controller is used to implement a flyback converter that is intended for use in nonisolated, low power, POE applications. The circuit has a nominal 48V input and supports the POE voltage range of 36V to 57V. The output voltage is 2.5V at 350mA.

App note: 1 kV SenseFET integrated power switch

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App note from ON Semiconductors on their FSL4110LR power switch for SMPS power supplies. Link here (PDF)

Some industrial equipment that are supplied from a threephase AC power source such as industrial drives and energy meters often need an auxiliary power supply stage that can provide a regulated low-power DC source for analog and digital circuitry.

This power supply stage requests special specifications such as;
– Wide AC input voltage: 45 VAC to 460 VAC
– Robust system against high line surge
– Protection against magnetic contact test
– Large output capacitance to keep long hold-up timeafter power-off

App note: Programmable analog functions

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Another app note from ON Semiconductors about various digital potentiometers application. Link here (PDF)

Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller. Analog circuits are made programmable by using digital potentiometers (POTs) to vary the key circuit parameters. This application note provides the analog design engineer with basic reference designs and circuit ideas for controlling the key parameters of analog circuits using digital POTs connected to a computer bus or microcontroller.

App note: Digital potentiometer (POT) to control LED brightness

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Controlling LED brightness through digital potentiometer and a LED driver from ON Semiconductor. Link here (PDF)

Light-emitting diodes (LEDs) require a regulated current, and their brightness is proportional to the current that flows through them. Some LED drivers use an external resistor to set the LED current. A digital POT can replace a discrete resistor with the advantage of providing an adjustable value allowing the LED brightness to dynamically change. Most digital POT circuits have the ability to store permanently the resistor value in non-volatile memory.

App note: USB On-The-Go (OTG) basics

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USB OTG explained in this app note from Cypress Semiconductors. Link here

This application note discusses several aspects of OTG functionality. The note introduces end-applications and different types of cables and connectors involved with OTG. It also describes the OTG protocol state changes when both Mini-A and Mini-B devices are connected .The host negotiation protocol (HNP) and session request protocol (SRP), which are part of the OTG protocol, are also explained.

App note: Meeting transient specifications for electrical systems in military vehicles

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Hardened circuit protection against voltage spikes and surges tackled in this app note from Vicor. Link here (PDF)

Electrical systems in military vehicles are normally required to meet stringent transient requirements. Typical of these specifications is the MIL-STD-1275B. Although the specified levels of these surges and spikes are outside the capability of Vicors Maxi, Mini, Micro Series modules, it is quite possible, with simple circuitry, to make the 24V input (18 – 36V input range) DC-DC converter modules compliant to these specifications for the 28V vehicle voltage system. Other electro-magnetic compatibility requirements, such as MIL-STD-461E and/or DEF-STAN 59-41, apply to military vehicles, but these are outside the scope of this application note. In order to meet additional conducted emission requirements an input filter, preceding the transient protection circuit covered in this application note, will be required.

App note: Intelligent lighting controller measures ambient light and tracks time

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Implementation on ambient light and time tracking luminaires controller from MAXIM Integrated, Link here

This reference design explains how to design an intelligent lighting controller that senses and measures the ambient light level with an ambient light sensor (ALS). Equipped with a real-time clock (RTC), the controller also knows when to turn lighting on or off at specified times.