by Hua (Walker) Bai:
The meaning of the term “high power LED” is rapidly evolving. Although a 350mA LED could easily earn the stamp of “high power” a few years ago, it could not hold a candle to the 20A LEDs or the 40A laser diodes of today. High power LEDs are now used in DLP projectors, surgical equipment, stage lighting, automotive lighting, and other applications traditionally served by high intensity bulbs. To meet the light output requirements of these applications, high power LEDs are often used in series. The problem is that several series-connected LEDs require a high voltage LED driver circuit. LED driver design is further complicated by applications that require fast LED current response to PWM dimming signals.
Design Notes: 60V, Synchronous Step-Down High Current LED Driver - [Link]
By Ashok Bindra:
The use of low-dropout regulators, popularly known as LDOs, is common in many applications today because they provide a simple and inexpensive way to regulate an output voltage that is stepped-down from a higher input voltage. In addition, linear LDO voltage regulators contribute very-low noise as compared to switching regulators.
Nonetheless, to keep system power consumption low, such regulators must also feature ultra-low quiescent current (IQ) while providing excellent dynamic performance to ensure a stable, noise-free voltage rail, suitable for driving IC loads such as microprocessors, FPGAs, and other devices on the system board.
Selecting the Right Ultra-Low Quiescent-Current LDO Regulator - [Link]
Got a buck? Make a charger for LiR2032 coin cells. It could hardly be cheaper or easier.
This Lithium battery charger circuit board, based around a TP4056 chip, will set you back all of $0.90. That may be an overestimate. I won an auction this week for 5 of them and paid $1.36, shipping included.
$1 Lithium Coin Cell Charger - [Link]
By Steven Keeping:
Power management in portable devices is one of the toughest challenges faced by electronic engineers. The consumer demands instant response from their device, lots of functionality, and a large, bright and colorful touchscreen. Moreover, many of these portable devices now incorporate wireless connectivity that places further demand on the cell. And yet, the user expects the battery, a sensitive lithium ion (Li-ion) cell that requires careful recharging from a number of sources including USB sockets, to last for at least a day and then refresh quickly.
Designing a power management system to meet these conflicting problems is tough. However, there are some proven design techniques that help extend battery life. Moreover, the key semiconductor vendors have made life a little easier by offering power management units (PMUs) that integrate some, or even all, of the functionality needed for the efficient power supply of portable devices.
Design Techniques for Extending Li-Ion Battery Life - [Link]
From time to time I get requests to make some high power switching, so I decided to design a solid-state relay that could handle a lot of different situations. The most common use for it I have is refurbishing old ceramic kilns. Since our technical life is close to the stage (both theatre and music), I also wanted it to be usable as a dimmer module. And, just for kicks, as a single phase AC motor speed controller, in case we would want that.
A solid-state relay with I2C interface - [Link]
by Publitek European Editors:
Power MOSFETs have become very popular in power electronics designs because of their low capacitance and good high-frequency switching characteristics. They have reached into many applications and are helping to open up new markets in applications, from hybrid and electric vehicles through solar power to extreme-environment exploration. The unifying factor of these environments is heat. Automotive engines and solar panels can generate heat that pushes junction temperatures in power devices far higher than 100°C. Such heat can badly affect power semiconductors that are not designed to cope. Power semiconductors all have temperature limitations. Leakage current increases with temperature and this can accelerate effects that lead to breakdown conditions that can damage circuitry and cause other hazards.
MOSFETs that Can Take the Heat - [Link]
New 6W DC/DC module series TEN5 won´t be scared neither of a very fluctuating input voltage, that´s why it´s ideal even for battery-operated applications.
Series TEN5 is a well proven reliable series of insulating DC/DC modules with a fixed output voltage, in case of TEN5-2411WI it is 5V. TEN5 series is available in so to say “basic” version with a 2:1 input voltage range and also in this „WI – wide input“ version, with a 4:1 ratio. In the most of cases, it´s probably possible to choose an appropriate type, for example TEN5-1211 with an input voltage of 9-18V, which is for example ideal for 12V applications with Pb accumulators (SLA). However namely for the mobile applications it can be beneficial, if a given device could be powered also by for example 24V, used in cargo trucks.
TEN5-2411WI with an input voltage of 9-36V and 5V/1A output is suitable this new type from our stock offer. Besides mentioned wide range of input voltages it also features a good efficiency (79% typ.) and excellent regulation at a change of input and/or load. Enhanced operating temperatures range (-40 to +85°C) and resistance to a continuous shortcut make it suitable even for demanding applications. Also useful is the built-in filter to meet EN55022 Class A and FCC level A. Metal shielded package in a standard DIP-24 package with an insulated base plate simplifies PCB design and also assembly to a PCB. In the TEN5 series can be found 2 versions: with input voltages of 9-36V or 18-75VDC with various output voltages, including symmetrical ones.
Detailed information can be found in the TEN5-WI datasheet.
TEN5-2411WI – don´t be limited by an input voltage - [Link]
This is a simple TRIAC AC load dimmer used to control the power of a resistive load such as incandescent lamp or heater element. The max load it can handle is 400VA. Such a circuit is often found on cheap commercial light dimmers and is proven to work reliable for the rated power.
400VA AC Light Dimmer - [Link]
Anthony H Smith writes:
The circuit in Figure 1 lets you switch high-voltage power to a grounded load with a low-voltage control signal. The circuit also functions as a submicrosecond circuit breaker that protects the power source against load faults. Power switches to the load when you apply a logic-level signal to the output control terminal. When the signal is lower than 0.7V, transistor Q3 is off and the gate of P-channel MOSFET Q4 pulls up to the positive supply through R6, thus holding Q4 off. During this off condition, the circuit’s quiescent-current drain is 0A.
Inexpensive power switch includes submicrosecond circuit breaker - [Link]
Wireless power. It’s less sci-fi sounding than it once was, thanks to induction charging like that based on the Qi standard, but that’s still a tech that essentially requires contact, if not incredibly close proximity. Magnetic resonance is another means to achieve wireless power, and perfect for much higher-demand applications, like charging cars. But there’s been very little work done in terms of building a solution that can power your everyday devices in a way that doesn’t require thought or changing the way we use our devices dramatically.
Cota By Ossia Aims To Drive A Wireless Power Revolution And Change How We Think About Charging - [Link]