by Steven Keeping @ digikey.com
Switching DC-to-DC voltage converters (“regulators”) comprise two elements: A controller and a power stage. The power stage incorporates the switching elements and converts the input voltage to the desired output. The controller supervises the switching operation to regulate the output voltage. The two are linked by a feedback loop that compares the actual output voltage with the desired output to derive the error voltage.
The controller is key to the stability and precision of the power supply, and virtually every design uses a pulse-width modulation (PWM) technique for regulation. There are two main methods of generating the PWM signal: Voltage-mode control and current-mode control. Voltage-mode control came first, but its disadvantages––such as slow response to load variations and loop gain that varied with input voltage––encouraged engineers to develop the alternative current-based method.
Today, engineers can select from a wide range of power modules using either control technique. These products incorporate technology to overcome the major deficiencies of the previous generation.
This article describes voltage- and current-mode control technique for PWM-signal generation in switching-voltage regulators and explains where each application is best suited.
Voltage- and Current-Mode Control for PWM Signal Generation in DC-to-DC Switching Regulators - [Link]
Voice Modulator project is designed around HT8950A to provide two special sound effects viz. Vibrato & Robot.
This project provides two special effects: vibrato and robot. The vibrato effect is generated by alternating the frequency of an input signal up and down at a rate of 8Hz. The robot function, on the other hand, converts an input voice into a robot voice. Both effects can be selected depending on which pin is triggered, either ROB or VIB. For the output frequency level shifting, the chips provide seven steps which can be selected from the two groups of pins namely, SW0, SW1 and SW2 for electronic direct selection and ROB, TGD, TGU and VIB for push button selection.
Voice Modulator (Sound Effects) - [Link]
Of the many low-dropout (LDO) regulators used to regulate voltage in electronic systems, some are specifically designed for low-noise operation. The MAX8887 low-noise LDO, for example, achieves a noise voltage of only 42µVRMS over the 10Hz to 100kHz range. Applications such as the ultra-low-noise oscillators required in instrumentation, however, require even lower noise. To fulfill that requirement, this project features the MAX6126 and a combination of low-noise components and filtering that achieves an output noise of only 6nV/√Hz at 1kHz
Ultra-Low-Noise LDO - [Link]
by Naomi Price & Martin Rowe @ edn.com:
USB data-acquisition modules offer good value and ease of use, which makes them an attractive choice for manufacturing test. But before you use the modules in a manufacturing test system, you need to take steps to protect them. During manufacturing test of circuit boards or subassemblies, a defect in an assembly may result in a condition that damages a data-acquisition module.
Test Ideas: Protect USB measurement circuits - [Link]
by By Ben Coxworth @ gizmag.com:
It’s the big paradox of emergency-use flashlights … by the time you eventually need to use them, their batteries have died. Eton’s new Blackout Buddy H2O, however, will reportedly still work after sitting for up to 10 years. And to turn it on, you just add water.
This latest member of the Blackout Buddy line has a magnesium-oxide battery, which starts delivering power to the light’s three LEDs when exposed to H2O. To initially fire it up, you dip it into a small cup of water, or pour water into its battery compartment. After that, it will keep going continuously for up to 72 hours – if it starts to dim within that time, you simply add more water.
Blackout Buddy H2O runs on water to provide emergency lighting - [Link]
Faster, smaller, greener computers, capable of processing information up to 1,000 times faster than currently available models, could be made possible by replacing silicon with materials that can switch back and forth between different electrical states.
The present size and speed limitations of computer processors and memory could be overcome by replacing silicon with ‘phase-change materials’ (PCMs), which are capable of reversibly switching between two structural phases with different electrical states – one crystalline and conducting and the other glassy and insulating – in billionths of a second.
Quick-change materials break the silicon speed limit for computers - [Link]
IBM has not only perfected a method of growing wafer scale graphene as a potential material for the post-silicon era, but has found a way to use it today to dramatically cut the cost of GaN LEDs.
IBM Grows Wafer Scale Graphene – [Link]
The MAX6369-74 series watchdog-only supervisors are available in tiny SOT23-8 packages and have selectable watchdog timeout periods (1.7ms to 104s), start-up delays (1.7ms to 104s) and output pulse widths (1.7ms and 170ms) depending on the part selected and the state of 3 pins (SEL0, SEL1, SEL2). These parts have several advantages over the historical “555” solutions. As well as the lower supply current (20µA max instead of 120µA max at 5V supply) the overall solution takes much less board area with the smaller package and the absence of large timing resistors and capacitors.
MAX6369 Series Watchdog Timers – [Link]
Nixie, a tiny wearable quadrocopter camera on a wrist band:
Team Nixie is developing the first wearable drone camera, which can be worn around your wrist. The team will be presenting their prototype for the Intel Make It Wearable Challenge Finale on November 3, 2014 in San Francisco.
Wearable quadrocopter - [Link]