Solutions Search - Monitor, Control and Protection
I2C Primer: What is I2C? (Part 1)
Sep 2nd 2016
Introduction:
The Inter-Integrated Circuit (I2C) bus is a two wire serial interface originally developed by the Phillips Corporation for use in consumer products. It is a bi-directional bus that is easily implemented in any IC process (NMOS, CMOS, bipolar) and allows for simple inter-IC communication. Connections are minimized ...
LTspice SOAtherm Support for PCB and Heat Sink Thermal Models
Sep 1st 2016
The SOAtherm model distributed with LTspice software and simplifies Hot Swap and Surge Stopper designs by verifying directly within a circuit simulation that a particular MOSFET’s Safe Operating Area (SOA) is not exceeded. This article assumes a basic understanding of the SOAtherm model. If you are not familiar with SOAtherm, ...
6A Monolithic Synchronous DC/DC Step-Down Converter with Digital Power System Management
Aug 10th 2016
Design Note 554: Introduction
Digital Power System Management (PSM) controllers usually target high current point-of-load (POL) applications. Lower current applications, with up to 6A load current, can also benefit from PSM features. The LTC®3815 is a 6A monolithic synchronous stepdown converter with digital power monitoring ...
95% Efficient at 2MHz 42V Sync Buck
Jun 24th 2016
Linear Technology’s family of high voltage synchronous step-down DC/DC switching regulators offer up to 95% efficiency. Switching at 2MHz, these low EMI parts utilize the Silent Switcher technology. Other features include spread spectrum frequency modulation, ultra-low quiescent current and are available with single, dual, ...
Negative Voltage Ideal Diodes (Diode-OR Controllers)
May 23rd 2016
An ideal diode (also referred to as a diode-OR controller and more generally as a PowerPath controller) is a robust, expanded functionality replacement for a discrete power diode. It consists of a MOSFET in place of the diode to provide a low voltage drop, low power dissipation switch that connects a power ...
LTspice: Using Time-Dependent Exponential Sources to Model Transients
May 15th 2016
When working with Surge Stoppers or Hot Swap Controllers, occasionally there is a need to simulate a circuit's behavior with a specified voltage or current transient. These transients are usually modeled using a double exponential waveform characterized by a peak voltage, a rise time (usually 10%–90%), a fall time to 50% ...
Primer on PowerPath Controllers, Ideal Diodes & Prioritizers
Apr 29th 2016
Electronic systems powered by multiple DC sources are commonplace - they include handheld devices (USB port and battery), portable instruments (wall adapter and battery), and high-availability servers (main and redundant/auxiliary supply rails). Selecting the correct input supply to power the system is not a trivial ...
Powering Altera Arria 10 FPGA and Arria 10 SoC: Tested and Verified Power Management Solutions
Feb 19th 2016
Design Note DN549: Introduction
FPGA development kits allow system developers to evaluate an FPGA without having to design a complete system. Figures 1 and 2 show Altera’s new 20nm Arria 10 FPGAs and Arria 10 SoCs (System-on-Chip) development boards. These boards are tested and verified by Altera, exemplifying best design ...
High-Voltage Amplifier Extends Coulomb Counter Range to +/-270V
Jan 22nd 2016
Introduction
A coulomb counter can measure charge that flows into or out of a battery. Small, dedicated devices such as LTC2941 or LTC2943 can directly interface with low to medium battery voltages, up to about 20V. You can extend the input operating range of the measurement circuit by using a high-voltage amplifier as a level ...
Shutdown with the LT3080x Current Source Reference Linear Regulators
Jan 21st 2016
Current Source Reference Linear Regulators
In many low noise applications, a linear regulator is an ideal solution for the power conversion due to its very low output voltage noise and low electromagnetic noise generation (compared to a charge pump or a switching regulator). The LT308x linear regulator family is ideal for these ...
Power Supply Sequencing Simplified
Dec 7th 2015
Design Note 1037: Introduction
Designing a multiple power supply system is challenging. The power supply designer’s workload multiplies with each additional supply rail. The designer must consider the dynamic environment of coordinated power supply sequencing and timing, generating power-on reset, monitoring for faults ...
Using a Current Sharing Controller with Non-Redundant Supplies
Nov 30th 2015
Design Note 1036: Introduction
The LTC4370 is a 2-supply current sharing, diode- ORing controller that uses MOSFETs to form ideal diodes. In this way, the LTC4370 can actively balance the output currents of two supplies, even those with unequal output voltages. For two unequal voltage input supplies, the forward voltage ...
Optimize Sense Resistor Cost and Accuracy for RTD Temp Measurement when Using LTC2983 Temp-to-Bits IC
Oct 19th 2015
The temperature measurement using a RTD, or a Thermistor, is really a measurement of resistance. RTDs and Thermistors change their resistance with temperature. Once the resistance of the probe is measured, and assuming that the Resistance as a function of temperature is known, the temperature of the probe can be calculated. ...
Using the LTC2983 with 18 2-wire RTDs
Sep 18th 2015
Introduction
A number of times I have come accross system definitions calling for use of a large number of temperature probes. Large number is in the eye of the beholder, of course, but it still brings up a question of how many sensors can interface to the LTC2983, a device that after all boasts 20 analog inputs. Well, let's ...
Achieving Low On-Resistance with Guaranteed SOA in High Current Hot Swap Applications
Jul 29th 2015
Introduction
The requirement for live insertion and removal in high current backplane applications demands MOSFETs that exhibit both low on-resistance during steady state operation and high Safe Operating Area (SOA) for transient conditions. Often, modern MOSFETs optimized for low on-resistance are unsuitable for high SOA Hot ...
100V Micropower Voltage Monitor Provides Flexible Monitoring of Positive and Negative Rails Simultaneously
Jul 22nd 2015
Flexible supply monitoring that eases design and provides high accuracy, at a low current cost, is in high demand in today’s power conscious world. Typical supply monitors comprise a comparator with a reference, and an external divider to set the exact trip points. Unfortunately, the divider can, itself, draw more current ...
Dual 9A, Step-Down μModule Regulator with Digital Power System Management
Jul 16th 2015
Design Note 542: Introduction
The LTM4675 is a dual 9A or single 18A step-down μModule® (micromodule) DC/DC regulator featuring remote configurability and telemetry monitoring of power system management (PSM) parameters over PMBus—an open standard I2C-based digital interface protocol. Its 6mm × 11.9mm × ...
Paralleling Linear Regulators Made Easy
May 21st 2015
Linear regulators provide a simple, low noise solution for dc-dc regulation. However, at higher Vin-Vout differentials the low efficiency and high power dissipation of linear regulators limits the ammount of output current that can realistically be delivered. Connecting multiple linear regulators in parallel spreads the ...
LT Programming Hex File Format Documentation -- In Circuit Programming
Mar 26th 2015
Purpose of Document
The purpose of this document is to clearly articulate the structure of the LT Programming Hex file in such a way that test engineers can build infrastructure to parse these files and execute programming logic to successfully program one or more LT Digital Power Product devices in cicruit, during test, or ...
LTC4218 12V / 100A Hot Swap Design for Server Farms
Mar 18th 2015
Cultivate reliability on the farm with a properly designed Hot Swap circuit.
Introduction
As data centers servicing the cloud grow in speed and capacity, backplane supplies are called on to deliver currents that push the performance boundaries of Hot Swap™ components. Hot Swap solutions allow boards to be inserted and ...
LTC4226 Parallel MOSFETs in Hot Swap Circuits
Mar 13th 2015
The Good, the Bad, and the Ugly
Introduction
While it is often desirable, and sometimes absolutely critical, to use multiple parallel MOSFETs in Hot Swap™ circuits, careful analysis of Safe Operating Area (SOA) is essential. Each additional parallel MOSFET added to a circuit improves the voltage drop, power loss, and ...
Linduino PSM
Mar 12th 2015
While many engineers use a dongle and tools to configure Power System Management devices via PMBus, a growing number of designs are adding Board Management Controllers, or connecting their PMBus to an existing microcontroller or application processer. At LTC, the dongle/tool option is comprised of a DC1613 and LTpowerPlay, and ...
Understanding Power Monitor Accuracy
Feb 20th 2015
Measurement of a system’s power consumption during a final factory test (before deployment into the field) is a prudent part of a test program for any product. But there is an increasing emphasis to bring this functionality into the product itself for “run-time” monitoring of power, current, supply voltage, ...
Loop Gain and its Effect on Analog Control Systems
Jan 26th 2015
Abstract
This article brings together the ideas of open loop gain, closed loop gain, gain and phase margin, minimum gain stability and shows how these parameters are interrelated in a feedback system. It examines loop gain in terms of a theoretical control system as well as practical electronic circuits, including linear regulators.
Introduction
Bob ...
Surge Stoppers Ease MIL-STD-1275D Compliance
Nov 25th 2014
Introduction
A military vehicle is a tough environment for electronics, where the potential for damaging power supply fluctuations is high. U.S. Department of Defense MILSTD- 1275D sets down the requirements for electronics when powered from a 28V supply, ensuring that electronics survive in the field.
MIL-STD-1275D compliance ...
LTspice: SOAtherm Tutorial
Oct 8th 2014
Verifying that a Hot Swap design does not exceed the capabilities of a MOSFET is a challenge at high power levels. Fortunately, thermal behavior and SOA may be modeled in circuit simulators such as LTspice IV® . The SOAtherm-NMOS symbol included in LTspice contains a collection of MOSFET thermal models developed by Linear ...
Output Voltage Noise Measurements for Linear Regulators
Sep 20th 2014
Linear regulators provide a simple, non-switching DC/DC converter solution with low component count, small solution footprint and low output voltage noise. These attributes make them well-suited for applications that have power supply noise constraints, have limited board space and are averse to magnetics. Applications ...
LTC3788 Generates High Voltages Using a Two-Stage Boost Converter
Sep 17th 2014
Generating high voltages from low level sources is not an easy task. Engineers are facing the following problems when they try to implement single stage boost at high step-up ratios.
Limitation of maximum duty cycle in boost controllers
Sharp decrease in efficiency at long duty cycles
High peak currents and EMI challenges ...
LTspice: Modeling Safe Operating Area Behavior of N-channel MOSFETs
Aug 22nd 2014
Introduction
Often the most challenging aspect of Hot Swap™ circuit design is verifying that a MOSFET’s Safe Operating Area (SOA) is not exceeded. The SOAtherm tool distributed with LTspice IV® simplifies this task, allowing a circuit designer to immediately evaluate the SOA requirements of an application and ...
LTC Power System Management Tips for Success
Jul 28th 2014
Here are some tips to make sure you get the most out of Linear Technology's Power System Management (PSM) products by using them the way they were intended. Follow these rules to stay out of trouble. Rule #1: When Sharing is Good
a) Always connect SHARE_CLK pins together. This keeps all LTC PSM devices on a common ...
Control the Voltage of a Remote Load Over Any Length of Copper Wire
Jul 8th 2014
Introduction
A common problem in power distribution systems is loss of regulation due to the cable/wire voltage drop between the regulator and the load. Any increase in wire resistance, cable length or load current increases the voltage drop over the distribution wire, increasing the difference between actual voltage at the ...
10A μModule Step-Down Regulator with Advanced Input and Load Protection
May 7th 2014
Introduction
Bus voltage surges pose a danger not only to the DC/DC converter, but also to the load. Traditional overvoltage protection schemes involving a fuse are not necessarily fast enough, nor dependable enough to protect loads such as FPGAs, ASICs and microprocessors. A better solution is to accurately and quickly detect ...
Dual 13A μModule Regulator with Digital Interface for Remote Monitoring & Control of Power
Jan 15th 2014
Digital Power System Management: Set, Monitor, Change and Log Power
Managing power and implementing flexibility in a high rail count circuit board can be challenging, requiring hands-on probing with digital voltmeters and oscilloscopes, and often rework of PCB components. To simplify power management, especially from a remote ...
LT4321/LT4275 LTPoE++/PoE+/PoE PD Controller TechClips
Oct 24th 2013
Power over ethernet is a continuing trend in the Ethernet world. The current IEEE standard allows for up to 25.5W of PD input power. LTPoE++ is Linear Technology's solution to meet the demand for greater power with 38.7W, 52.7W, 70W and 90W power levels.
Heat generated by Power Over Ethernet powered device (PD) ...
Meet Green Standards in 24VAC and 12VAC Lighting Systems: Replace Halogen Bulbs with LEDs Driven by High Power Factor, High Efficiency Converter
Oct 17th 2013
LEDs are increasingly used in 24VAC and 12VAC lighting systems as a robust, energy efficient and high performance alternative to halogen lamps. Power converters that drive the LEDs should have a high power factor (above 90% in order to meet generally accepted green standards), should be efficient, use a minimal number of components ...
Bench Comparison of Two Overvoltage Protection (Crowbar) Methods: MOSFET vs. Silicon Controlled Rectifier
Oct 10th 2013
Introduction
As electronic sub-systems play a significant role in the reliable and safe operation of the overall product, adding an overvoltage protection circuit around the DC/DC step-down regulator may be advisable to prevent damage to the latest digital logic processors considering their absolute maximum voltage (<2V ...
Active Bridge Rectifiers Reduce Heat Dissipation within PoE Security Cameras
Oct 1st 2013
Introduction
Power over Ethernet (PoE) has been embraced by the video surveillance industry as a solution to an age-old problem: complicated cabling. For instance, a basic, traditional fixed-view security camera requires two cables: one for power (10W to 15W from a 24V AC or 12V DC), and a separate, coax cable for the video ...
PMBus Spec Working Group Issues Version 1.3 For Review
Sep 26th 2013
The PMBus Specification Working Group has released the PMBus 1.3 specification proposal for adopter review. The updated specification adds features and improves performance of PMBus 1.2 and adds AVS Bus (Part III). If the Working Group achieves its goals, the new specification will complete its review process and be approved ...
High Performance Single Phase DC/DC Controller with Power System Management
Aug 1st 2013
Design Note 517: Introduction
The LTC®3883 is a single phase synchronous stepdown DC/DC controller featuring a PMBus interface for digital control and monitoring of key regulator parameters. It has integrated MOSFET gate drivers and can function either standalone or in a digitally managed system with other Linear Technology ...
Fault Management Architecture
Jul 11th 2013
I recently had some enquiries into using PMBus communication to manage faults vs. built-in fault management. The question was two fold: what is the impact of using PMBus to make fault-off decisions, and what can be done to build system wide fault logs?
Before I dig into these two uses of PMBus, let’s consider what is ...
The Dreaded "File Test" on an LT4320 Ideal Diode Bridge Controller
Jul 9th 2013
The LT®4320/LT4320-1 are ideal diode bridge controllers that drive four N-channel MOSFETs, supporting voltage rectification from DC to 600Hz. See how they can be used to replace conventional diodes:
By maximizing available voltage and reducing power dissipation (see thermograph comparison below), ...
Prevent Your Next High Flying Product Launch From Being Grounded
May 7th 2013
A small investment in over-voltage protection for high value FPGAs, ASICs, and micro processors could pay dividends in reliability, safety and warranty costs
The widening gap between the 24V-28V intermediate bus commonly found in industrial, aerospace and defense systems and the input supply voltages of modern digital processors ...
Digital Loops Are Not the Same as Analog Loops
Apr 10th 2013
I recently heard a claim that at the output of a power converter, digital and analog loop are the same. The claim went like this:
“a power supply using digital power control techniques will appear identical to the end user as a power supply using analog power control techniques.”
This reminds me of the classic ...
LTM4641 TechClips - Efficiency, Output Overvoltage Protection, Overcurrent Protection and More
Feb 6th 2013
The LTM4641 is a 4.5V to 38V input, 0.6V to 6V output, 10A step-down μModule® regulator with comprehensive electrical and thermal protection for loads such as processors, ASICs and high-end FPGAs. The LTM4641 μModule regulator monitors input voltage, output voltage and temperature conditions. If any user-adjustable ...
System Monitor with Instrumentation-Grade Accuracy Used to Measure Relative Humidity
Jan 1st 2013
Because much can be deduced about a physical system by measuring temperature, it is by far the most electronically measured physical parameter. Selecting a temperature sensor involves balancing accuracy requirements, durability, cost and compatibility with the measured medium. For instance, because of its low cost, a small-signal ...
Digital Power: Why Should I Care About Accuracy?
Dec 17th 2012
We looked at why we care about the digital side of Digital Power in the last post, but what about the analog side of digital power? Does the accuracy at the other end of the Digital Power device matter? It turns out, it matters more than most people realize.
An example error budget
Let’s use an actual IC specification ...
Digital Power: Why Should I Care About Integration?
Dec 4th 2012
You have seen how Digital Power allows rails to work as a team, and how tools enable configuration and debug. Now it is time to step back and look at how Digital Power fits into a system. In particular, how Digital Power integrates with Board Controllers defined by industry standards.
Why should we care about standards?
In ...
Digital Power Debug
Sep 20th 2012
Introduction to the Powerstick System
A picture speaks a thousand words, so let’s just cut to the chase and look at the hardware and software we will be using.
Above you can see three Powersticks, each with 14 rails, and one green LED per rail to indicate power. On the bottom right is a 12V DC input, and a DC1613A ...
Digital Point of Load Converters vs. Digital Managers
Sep 1st 2012
When should you use a Point of Load Converter (POL) with PMBus, and when should you use a Digital Manager with old school POLs? In this post I will provide some heuristics for making this choice.
So as to not mislead, my goal is modest: to provide enough intuition to make a first pass choice, that becomes an area to explore ...
Digital Power Supervision and Telemetry
Aug 21st 2012
What does a Digital Power device do between start-up and shutdown? Two core functions are supervision and telemetry. Supervision is a fast acting safety feature that prevents damage to the device and/or load. Telemetry is an ongoing quality management feature.
A recent advertisement in Bodo’s Power Systems listed the ...
Digital Power Sequencing
Aug 14th 2012
Power Sequencing is a key component of Digital Power Architectures. In this post we will take a look at several ways to architect sequencing, and its consequences. In particular, we will see how design choices impact flexibility late in the design process.
Building Blocks of Power Conversion
Let’s take a look at our ...
Digital Power Management
Jul 31st 2012
Many Digital Power products use the industry standard PMBus to enable system architects to manage and control multi-rail power architectures. However, many people are uncertain how to apply PMBus to solve real world problems. Over the course of the coming months I am going to blog on different topics related to the practical ...
Using LTpowerPlay to Manage the LTC2978
Sep 17th 2010
The LTC2978 features enable power supply supervision, monitoring, sequencing and trimming with unmatched accuracy. These features combined with our easy to use GUI, assist the power supply designer in defining and implementing complex power management schemes in a fraction of the time previously possible. Fault logging capability ...
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