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]
Which are the key parameters for MOSFETs in typical DC/DC converter applications. by Publitek European Editors:
The silicon MOSFET has become a key component in the design of DC/DC converters, providing the high-speed switching and current-handling capability needed to implement high-efficiency, pulse-width-modulation-based control strategies. The drive towards higher efficiency is placing more intense demands on MOSFETs, particularly in designs that have constraints on size, reducing the amount of space that can be given over to heatsinks and other cooling assistance.
The trends are pushing towards the use of MOSFETs that offer reduced Rds(on), as well as offering low switching losses through good charge-storage characteristics. This article will examine a number of the key parameters for MOSFETs in typical DC/DC converter applications.
MOSFETs Target the Major Efficiency Losses in DC/DC Converters - [Link]
by Jon Gabay,
Low-power microcontrollers have done much to improve longevity in energy-harvesting systems. Clever architectures and use of low-power modes lets micros draw nanoamperes of current while preserving registers and configuration data. This allows designers to use smaller and less dense energy storage solutions that were not feasible in the past. Nevertheless, energy storage, which plays a key role in ambient-energy-harvesting systems, is still needed in most cases as a power buffer to store enough energy to provide the power bursts needed to acquire and transmit data during peak demand, particularly if data is going to be transmitted across a wireless network. These energy storage devices generally take the form of either a battery or a supercapacitor (supercap).
Supercapacitor Options for Energy-Harvesting Systems - [Link]
Linear Technology announced the LTC3330, a complete regulating energy harvesting solution that delivers up to 50mA of continuous output current to extend battery life when harvestable energy is available. The IC requires no supply current from the battery (Iq=0) when providing regulated power to the load from harvested energy and only 750 nA operating when powered from the battery under no-load conditions.
What are the key needs of an Energy Harvesting (EH) power supply? Well, first of all, battery redundancy power needs to be available at times when the ambient power is not available. Of course, we want to extend battery life by harvesting ambient energy from thermal, vibration, solar, etc. To make the front end of our power supply more versatile, it would be useful to be able to convert both AC (piezo, magnetic, etc.) or DC (solar) energy transducers with a fairly wide voltage range and also to have an input prioritizer that could decide whether to use the energy harvesting input or the battery input.
LTC3330 - LTC nano-power buck-boost DC/DC - [Link]