The LT®8310 is a resonant-reset forward converter controller that drives an external low side N-channel MOSFET from an internally regulated 10V supply. The LT8310 features duty mode control to generate a stable, regulated, isolated output using a single power transformer. With the addition of output voltage feedback, via opto-coupler (isolated) or directly wired (nonisolated), current mode regulation is activated, improving output accuracy and load response. A choice of transformer turns ratio makes high step-down or step-up ratios possible without operating at duty cycle extremes.
100 V Forward Voltage Controller - [Link]
A DIY 60W adjustable electrical load project from Electro-Labs:
In this project, we are building a useful board which should take place on your bench. It is an adjustable electrical load which can sink up to 5A @ 60W continuously. This board will come to aid when you need to draw an exact amount of current from a supply. For instance to learn the current rating of a power supply, measure the heat dissipated on a circuit element, discharge a battery etc.
The electrical load lets you monitor the current by using the ampermeter on it. A multiturn variable resistor is used to set the current precisely. The circuit is powered by a 15V-18V power adapter. A large heatsink on the board helps dissipating the heat generated on the MOSFET which is the main component used for limiting the current.
DIY 60W adjustable electrical load - [Link]
Here’s an Instructable about a DIY charger for car’s battery with an analog DC ammeter in the front panel. A PIC12F683-based control circuit is enclosed inside which adds some intelligence to this charger. The PIC MCU checks the terminal voltage of the battery being charged in every ten minutes using one of its analog inputs, and if it is found above a set threshold, the charging process is stopped. A relay switch is included into the circuit to connect/disconnect the charger output and the battery terminals.
PIC12F683 based battery charger - [Link]
Switch-mode regulator Traco TSR 0.5 will give you as much as you need. If you have an application, where 0.5A is sufficient, then the new series of DC/DC modules is ideal for you.
Maybe, it´s worth to ask a question, whether it makes sense to use a switch-mode regulator for such a low current? For sure yes, at least because of two reasons. If we need to create 3.3V from for example 12V, then at a current of 0.5A a power loss of 4.35W appears at a classic linear regulator. That´s already a quite considerable power, able to heat up a device – especially at smaller enclosures and a dense population on a PCB.
Another reason is energy saving – especially at battery powered devices. Switch mode power supplies (SMPS) have a “genial” feature, that thanks to their high efficiency we use practically whole power drawn from a source, i.e. if we need say 5V/0.5A from a 15V source – we won´t take from it 0.5A but only approx. 0,17-0,18A.
Novelty of company Traco Electronic – series TSR 0.5 is by its function very similar to well known, proven DC/DC regulators TSR1 or TSRN1. The main difference is in a smaller allowed current and a feelingly lower price . That ´s why this series is very suitable for any application, where a current of 0.5A will be sufficient. A big advantage can be a wide operating temperatures range from -40 to +90°C (power derating 5%/K at temperature above 80°C). Maximum input voltage of 32V enables a usage even at power supplying from various alternative energy sources with a big input voltage fluctuations.
This novelty is so far available in a version with 5V output voltage (TSR 0.5-2450) and soon there will be another.
Why to pay for the current, which you won’ t use? - [Link]
By Steven Keeping @ digikey.com:
Modular DC-DC switching voltage converters (or voltage regulators) are fully integrated devices that take away most of the complexity of power supply design — but not all. One of the key areas that are still left to the design engineer’s discretion is the choice of components for, and layout of, the energy storage and filtering circuits. In principle, these look like simple circuits comprising a few resistors, capacitors, and the energy-storage element, usually an inductor.
Capacitor Selection is Key to Good Voltage Regulator Design - [Link]
Maxwell Technologies have announced the addition of a 2.85 Volt, 3400-Farad cell to their K2 family of ultracapacitors. It is the most powerful cell available in the industry-standard 60 mm cylindrical form factor. Incorporating Maxwell’s DuraBlue™ Advanced Shock and Vibration technology it also claims to be the most ruggedized cell currently available making it suitable for high energy storage in demanding environments such as those typically encountered in public transit vehicles and transport applications.
3400 Farad Ultracapacitor - [Link]
By Sean Michael Ragan:
The Joule Thief (Wikipedia) is a well-known “instant gratification” hobby circuit that uses just a handful of components to pull off a pretty impressive parlor trick — using a single 1.5V battery, the Joule Thief can light a high-voltage blue or white LED that normally requires 3.5V or greater to turn on. Even more impressive, it can do so using a battery that is so drained of energy as to be counted “dead” for almost all other purposes. I have not measured this value myself, but it is commonly claimed that a Joule Thief can light a white LED from a battery with an open-circuit voltage as low as 0.6.
Bring “dead” batteries back to life with a toroid and the Joule Thief circuit. - [Link]
Due to some intermittent voltage drop issues on the first revision of PowerShield I refactored the design and released a new PowerShield R2 based on the LTC3525 fixed 5V booster that should address this issue. This is a much more expensive chip than the TPS61220, others have used the Linear Technology boosters with success so hopefully it’s more reliable, but price will reflect this. It also means there is no switching between 3.3V and 5V output any more. For 3.3V projects, a Lipo can be connected directly to Moteino and the onboard regulator will provide up to 250mA of current to the Moteino itself and any other peripherals attached.
PowerShield R2 released - [Link]
by Ashok Bindra:
Whether it is used for biasing avalanche photodiodes (APDs) found in optical receivers, driving photoflash tubes in flash cameras, or charging high-voltage capacitors, the need for high-voltage sources continues to grow. Consequently, in battery-powered units where the input supply voltage is low, step-up or boost DC/DC converters are required to generate voltages that can be several times the input. To address these requirements, suppliers such as Analog Devices, Linear Technology, Maxim Integrated, and Micrel Inc., among others, have produced boost converters with output voltages at 70 V and above.
This article examines such solutions and discusses the topologies and techniques used by each to boost output voltages by ratios of 10:1 or better in order to generate high-DC voltages from very-low DC inputs.
DC/DC Converter Topologies and Techniques to Obtain High Boost Ratios - [Link]
By Bill Saltzstein:
Switching DC/DC power supplies and regulators, regardless of whether IC, module, or chassis, are generally preferred over linear supplies, and with good reason. In general, they are much more efficient, resulting in reduced power use and cost, longer run time, and less heat to dissipate. (Note: There are cases where the linear supply may be more efficient, especially when the input/output voltage differential is small.¹)
However, there is a problem with switching supplies which affects many designs. Due to their inherent internal switching action, they generate more noise than linear supplies. The noise frequency is a function of the underlying switching frequency, which typically is between 100 kHz and several MHz, depending on design and application, and includes several harmonics.
Using Spread-Spectrum Techniques to Manage Switching Power Supply EMI - [Link]