Electronics-Lab.com Blog

Ashok Bindra writes:

In their most basic form, charge pumps are circuits that generate a voltage larger than the supply voltage from which they operate. Traditionally, charge pumps have been perceived to have limited voltage capability, offering performance that is seen as filling a niche in the range between low-dropout LDOs and switching regulators. Nonetheless, there are benefits that make them attractive for certain applications. For instance, charge pumps deliver higher efficiency with good thermal management and have the flexibility to step up a voltage, step it down, or invert the input voltage. Since they use capacitors to store and transfer energy, charge pumps also are simple to design and do not require an inductor, which can be more costly, has higher output-noise levels, and frequently lowers output-current capability.

Charge Pumps Tackle Higher-Voltage Applications - [Link]

Here is a great application note from Maxim describing the process of designing a high voltage LED driver. The guide goes step by step so it’s easy to follow it.

This application note details a step-by-step design process for the MAX16833 high-voltage high-brightness LED driver. This process can speed up prototyping and increase the chance for first-pass success. A typical design scenario is presented, along with example calculations based on the design constraints. Component selection trade-offs are discussed. A spreadsheet calculator is included to help calculate external component values. This application note focuses on the boost converter topology. However, the same process can be applied to other topologies as long as the underlying equations are understood.

Step-by-Step Design Process for the MAX16833 High-Voltage High-Brightness LED Driver - [Link]

Ronald Willem Besinga writes:

One of the basic usage of the TIMER peripheral on every microcontroller is to provide the accurate timing mechanism. Using the TIMER peripheral as the basic timing, we could easily develop a stopwatch and display it to the 8-Digit seven segment numeric LED display. Thanks to the Maxim MAX7219 chip which enable us to interface this 8-Digit seven segment LED display much easier using just three wires of the SPI (serial peripheral interface) to display the hour, minute, second, and hundredth of seconds to the 8-Digit seven segments LED display.

Build your own stopwatch using Maxim MAX7219 Serially Interfaced, 8-Digit LED Display Drivers - [Link]

Abstract: The reality of modern, small form-factor ceramic capacitors is a good reminder to always read the data sheet. This tutorial explains how ceramic capacitor type designations, such as X7R and Y5V, imply nothing about voltage coefficients. Engineers must check the data to know, really know, how a specific capacitor will perform under voltage. [by Mark Fortunato]

Temperature and Voltage Variation of Ceramic Capacitors, or Why Your 4.7µF Capacitor Becomes a 0.33µF Capacitor - [Link]

[MAXIM APP 5509] This document details the Oceanside (MAXREFDES9#) subsystem reference design, a 3.3V to 15V input, ±15V (±12V) output, isolated power supply. The Oceanside design includes a high-efficiency step-up controller, a 36V H-bridge transformer driver for isolated supplies, a wide input range, and adjustable output low-dropout linear regulator (LDO). Test results and hardware files are included.

Isolated power is required in many applications such as industrial and medical applications. The Oceanside design uses a step-up controller (MAX668), a 36V H-bridge transformer driver (MAX13256), and a pair of LDOs (MAX1659 x2) to create a ±15V (±12V) output isolated power supply from a wide range of input voltages. This general purpose power solution can be used in many different types of isolated power applications, but is mainly targeted for industrial sensors, industrial automation, process control, and medical applications.

3.3V to 15V Input, ±15V (±12V) Output, Isolated Power Supply - [Link]

The MAX31855 performs cold-junction compensation and digitizes the signal from a K-, J-, N-, T-, S-, R-, or E-type thermocouple. The data is output in a signed 14-bit, SPI-compatible, read-only format. This converter resolves temperatures to 0.25°C, allows readings as high as +1800°C and as low as -270°C, and exhibits thermocouple accuracy of ±2°C for temperatures ranging from -200°C to +700°C for K-type thermocouples. For full range accuracies and other thermocouple types, see the Thermal Characteristics specifications in the full data sheet.

MAX31855 – Cold-Junction Compensated Thermocouple-to-Digital Converter - [Link]

This table provides top-level characteristics for serial interface standards by which two or more digital devices can be connected for communication. Design engineers can use the table to compare interface options for their application based on the design constraints like number of signal lines, network size, speed, distance, noise immunity, fault tolerance and reliability.

Serial Data Communication Protocols Comparizon - [Link]

Maxims proprietary one wire devices have been popular with hobbyist for a long time. The small and incredibly accurate (for hobbist) DS18B20 and DS18S20 series of temperature sensors from this family of devices have been used on many platforms.

I too have used this temperature sensor, DS18B20 in particular in some of my hobby projects. But on all occasions the code routines that I used to interface the sensors, had been the hard-work of somebody else. However that did not matter as it solved my immediate purpose then. Comprehensive and easy to use routines are available for AVR, PICs and the Arduino Community so why rack your brains!

Interfacing Maxim OneWire (1-Wire) devices DS18B20 on TI Launchpad MSP-EXP430G2 - [Link]

dangerousprototypes.com writes:

This reference design from Maxim is a current controlled boost driver designed for long strings of LEDs. Driving many LEDs in series has advantages over driving them in parallel. In a parallel configuration each LED will need it’s own current limiting resistor or current control, while the series LEDs  make use of a single current controlled power supply. The driver must support the combined voltage of all the LEDs in the string. The reference design can supply up to 100 volts, which translates to around 30 LEDs.

App note: Current controlled boost driver for long LED strings - [Link]

Don Scansen writes:

Untapped energy surrounds us. Transducers to convert various energy sources into electricity that can be put to useful work are relatively straightforward to understand and implement. However, harvestable energy sources are intermittent, or at least very inconsistent, in terms of output. Many can provide only a few microwatts. Putting these very low energy sources to use requires efficient charge control electronics designed for low power.

In terms of performance, one of the most attractive energy harvesting power management ICs (PMIC) on the market is the MAX17710G+T from Maxim, which was designed from the ground up for energy harvesting and extracting the greatest amount of energy possible from the transducer element. As a result, it offers class-leading performance for this application. The PMIC allows very simple, low-cost solutions for battery charging and protection. The MAX17710G+T will provide good battery charging performance for a wide range of ambient sources and conditions. Useful power is extracted from levels as low as 1 µW and 0.8 V. Coupled to a very small form factor MEC (micro energy cell), it is a powerful combination for a broad range of energy harvesting applications.

A Hands-on Look at the Maxim MAX17710 Energy Harvesting PMIC - [Link]