App note from STMicroelectronics on high-side current sense RF noise filtering. Link here (PDF)
In an application such as a power supply or a DC-DC converter, the voltage output is generally noisy. Some spikes load the current. Alternatively, a temporary over voltage might occur creating either common mode or differential noise. Such high frequency signals may be demodulated by the current sensing device, resulting in an error in the current measurement.
Consequently, for power supply and DC-DC converter applications, it is necessary to filter the input path of the current sensing to improve the accuracy of the measurement. Such filters must be successfully implemented by choosing the right component values. If the wrong component values are selected, non-desired offset voltages and gain errors might be introduced, which compromise circuit performance.
App note from STMircoelectronics on the advantage of power schottky over bipolar diode in SMPS. Link here (PDF)
Nowadays, the Switch Mode Power Supply (SMPS) is becoming more widespread as a result of computer, telecom and consumer applications. The constant increase in services (more peripherals) and performance, which offers us these applications, tends to move conversion systems towards higher output power.
In addition to these developments dictated by the market, SMPS manufacturers are in competition, their battlefield being the criteria of power density, efficiency, reliability and cost, this last being factor very critical.
Today, SMPS designers of 12V-24V output have practically the choice between a 100V Schottky or a 200V bipolar diode. The availability of an intermediate voltage has become necessary to gain in design optimization.
App note from Maxim Integrated about their MAX17291 generating negative voltage from positive input. Link here
Many applications require the power supply to provide a negative voltage, such as LCD displays, gate drivers, embedded applications, op-amp circuits, etc,. This application note explains how to generate a negative output voltage from a positive input voltage using the MAX17291 boost converter IC.
The MAX17291 is a low quiescent current boost (step-up) DC-DC converter with a 1A peak inductor current limit and True Shutdown™. True Shutdown disconnects the output from the input with no forward or reverse current. The output voltage is set with an external resistor-divider. The MAX17291 IC can operate from 1.8V to 5.5V input supply and can output up to 20V.
App note from Maxim Integrated about adding additional current limiting circuit for their MAX38902 LDO. Link here
Current limit in a LDO establishes an upper threshold for the current delivered. In a low dropout linear regulator architecture, the input and output average currents, which are connected by a series pass-through transistor, are almost the same.
Why current limit? Any surge in the current demanded by the load and/or triggered by a load fault condition results in an additional input current draw. If the device is not over current limited then this additional current can result in unacceptable system performance like increased load ripple, output voltage going out of regulation and, if not limited, can lead to system failure as well. Hence, there is a need to limit the current against these conditions in the interest of safeguarding the associated electronics within and outside the LDO so that it gracefully handles the fault condition (like output short circuit) and auto-recovers when the fault is removed.
Tips from Maxim Integrated on how to measure efficiency on complicated multiphase converters. Link here
Due to the nature of multiphase buck converters, perceived efficiency varies for a static operating condition depending on the load and output voltage measurement connections, as well as the symmetry of the PCB layout. An engineer evaluating multiphase buck converters should understand the nuance of efficiency measurement that this article explores, as well as PCB layout. How to fairly compare efficiency of multiphase buck converters on different evaluation boards needs to be addressed. This application note explores the underlying reasons and offers a method for measuring the most accurate efficiency in a multiphase buck converter.
App note from Maxim Integrated on achieving a lower power sensing in analog front end. Link here
In precision signal conditioning and measurement applications, a delta-sigma ADC has often been preferred over a SAR ADC on account of high-resolution output and highly integrated internal blocks such as a PGA or GPIO voltage reference. However, in some circumstances, the delta-sigma ADC’s high resolution is not needed or cannot be achieved, and its high-power consumption becomes a drawback.
App note from Infineon on the basics of flash memories and their failure analysis recommendations. Link here (PDF)
Nonvolatile memory devices (like Flash) are often used in embedded applications that rely on the storage of system configuration, dynamic data, or both. This data needs to be retained during a power interrupt or power cycle. In case of a system malfunction, the reproducibility of the failure is influenced and depends on the state of the nonvolatile memory. This application note briefly explains the basic operation of Flash memory devices and recommends several analysis techniques.
App note from Infineon about quad SPI, an enhanced SPI protocol that provides four times data throughput at higher frequencies. Link here (PDF)
In order to manage the wide range of multimedia, graphics, and other data intensive content, embedded systems have evolved to offer more sophisticated features. These features place extra demands on the often-limited on-chip memory of the host controller (or MCU). External memories with parallel interface have long been used to extend the on-chip MCU’s storage limitations. Memories with a parallel address/data bus come in high pin-count packages and require more pins on the controller to communicate with.
The QSPI F-RAM supports single data rate (SDR) for all its SPI interface options up to 108 MHz, while it also supports the double data rate (DDR) up to 54 MHz but for specific opcodes. The 54-MHz DDR interface offers the same data throughput as the 108-MHz SDR but at half the frequency. Some systems preferably use DDR at reduced frequency than the high-speed SDR, which helps reducing the system core and I/O frequencies, thus system power without compromising the data throughput.
New development and manufacturing process produces extended temperature endurance of solid capacitors discuss in this app note from KEMET. Link here (PDF)
For decades the maximum recommended operating temperature of solid electrolytic capacitors was 125°C. Responding to needs in the automotive and downhole drilling industries passive component manufacturers developed surface mount tantalum capacitors rated at 150°C in 2002-2003. Since that time the industry has introduced high temperature capable tantalum capacitors generally in 25°C increments roughly every four years. Today multiple manufacturers have products rated at 230°C poised for market release.
App note from KEMET about supercapacitor’s leakage and self discharge and their differences in order to take account the back-up time of an application. Link here (PDF)
Supercapacitor is widely used for RTC backup application to provide power to RTC circuit in electronics when the power source to the system is disconnected. Self-discharge characteristics is one of the important characteristics to determine the backup time. Self-discharge current is often confused with leakage current characteristic.
Technical note from Vishay about linear resistor handling pulsed currents. Link here (PDF)
The power and thermal behavior of fixed linear resistors are mostly based on DC or RMS loads, but pulse loads, like single energy pulse or a continuous flow of pulses, become more and more an important factor in professional electronics.
App note from Silicon Labs on their hall-effect Si72xx magnetic sensor to sense position, count revolution and security system seal tamper sensing. Link here (PDF)
These devices all measure magnetic field in the axis perpendicular to the package. All of these parts share the attributes of low power, high sensitivity, and low noise. The simplest parts in this family have a single output pin that goes high or low at a certain magnetic field. Options are available to output the magnetic field by I2C, SENT, PWM or analog format, to put the part in a very low power sleep state (disable pin), to turn on an on-chip test coil (BIST) and to indicate when a higher than expected field has been detected (tamper).
App note from ON Semiconductors about LC823455 audio processor echo cancelling test results. Link here (PDF)
The canceller enables customers to improve the sound quality of hands free communication in wireless headset or other voice communication products.
App note from ON Semiconductors on their LC823455 audio processor noise cancelling test results. Link here (PDF)
The canceller enables customers to improve audio characteristics for products such as Wireless headsets, Wireless speakers or Voice recorders.
A hardware design guide using NXP’s PN7150 full featured NFC controller. Link here (PDF)
This document is intended to provide an overview on how to integrate the NFC Controller PN7150 from hardware perspective.
It presents the different hardware design options offered by the IC and provides guidelines on how to select the most appropriate ones for a given implementation.
In particular, this document highlights the different chip power states and how to operate them in order to minimize the average NFC-related power consumption.
App note from ROHM Semiconductor on their voltage detectors IC primarily used in microntroller reset circuitry. Link here (PDF)
Texas Instruments’ switching noise on audio reduction using spread spectrum tech. Link here
Automotive systems have many regulations and requirements, from electromagnetic interference (EMI) to thermals to functional safety, but one consideration that stands above the rest when it comes to immediate consumer dissatisfaction is audible noise. In this technical article, I’ll discuss common sources of audible noise, and how devices with TI’s dual random spread spectrum (DRSS) technology can help you eliminate audible noise in your designs.
Technical designs from Texas Instruments on accurate DC power supplies. Link here
Test and measurement applications like battery test, electrochemical impedance spectroscopy and semiconductor test require accurate current- and voltage-output DC power supplies. The current and voltage control accuracy of the equipment need to be better than ±0.02% of the full-scale range over a ±5°C ambient temperature change. The accuracy largely depends on temperature drift of the current-sense resistor and amplifiers. In this article, you will learn how different components affect system accuracy, and how to choose suitable components for a precision DC power-supply design.
App note from ON semiconductor on proper terminations when using advance CMOS logic to minimize power consumption. Link here (PDF)
Advanced CMOS logic such as ON Semiconductor’s FACT® logic, has extended CMOS performance to the level of advanced bipolar technologies. While high−performance design rules that are currently utilized for bipolar designs are also applicable to CMOS, power consumption becomes a new area of concern in high−performance system designs.
One advantage of using advanced CMOS logic is its low power consumption. However careless circuit design can increase power consumption, possibly by several orders of magnitude. A simple FACT gate typically consumes 625 W/MHz of power; at 10 MHz, this translates to 6.25 mW. A 50 W parallel termination on the line will use over 361 mW with a 50% duty cycle.
New app note from ON Semiconductor about thier LC709204F fuel gauge chip. Link here (PDF)
LC709204F is a Fuel Gauge for 1−Cell Lithium−ion/Polymer batteries. It is a part of our Smart LiB Gauge family of Fuel Gauges which measure the battery RSOC (Relative State Of Charge) using its unique algorithm called HG−CVR2. The HG−CVR2 algorithm provides accurate RSOC information even under unstable conditions (e.g. changes of battery; temperature, loading, aging and self−discharge).
This application note will explain how to initialize various parameters for the selected battery to start a higher accuracy gauging. Users can set various registers based on their application requirement using the notes, guidelines and examples given in this note. Sample program codes explained at the end of the note will provide various guideline on how this device communicates with the host side application processors.