Since its invention over a half-century ago by Hanz Camenzind at Signetics, the familiar 555 analog timer (in league with its updated pin-compatible CMOS descendants) has become an iconic design element incorporated into useful standardized functional blocks almost too numerous to count...
Inverted MOSFET helps 555 oscillator ignore power supply and temp variations
Linear opto-couplers and the loop gain 'booby trap'
A power supply that I was examining used an opto-coupler in its feedback path for control of its output voltage. This is a commonplace and well established design approach, but the feedback loop’s unconditional loop stability was not altogether a certainty...
STMicroelectronics' integrated automotive audio amplifier combines high-definition sound with class-G efficiency
STMicroelectronics’ TDA7901 automotive amplifier integrates a buck controller for class-G power switching and supports high-definition audio, a market-unique combination for great listening and high efficiency...
Switching regulator efficiently controls white-LED current
A few years ago, manufacturers specified their white, but dim, LEDs for a maximum forward-current rating of 20 mA. Today's white LEDs deliver more light and thus must operate at ever-higher bias currents...
Two-wire, four-by-four-key keyboard interface saves power
You can use a microcontroller that includes an ADC to design a two-wire-plus-ground keyboard interface. For example, you can use a resistive voltage divider to identify a pressed key...
Flusso launches world's smallest air velocity sensor
Flusso has announced another breakthrough for the flow sensing market: the world’s smallest air velocity sensor. The FLS122 has a footprint of just 3.5 by 3.5 mm...
Latching power switch uses momentary-action pushbutton
Most inexpensive pushbutton switches, particularly pc-board-mounting and membrane types, have momentary action. Latching types are often larger and relatively expensive...
Tapped inductor, boost regulator deliver high voltage
When you face the task of generating a regulated voltage that's higher than the available power-supply voltage, you may consider a boost regulator. Although a boost converter can in theory generate almost any voltage that's higher than its input, practical considerations limit the output to approximately eight times its applied voltage...
Off-the-shelf watchdog serves in a pinch
The performance of the watchdog circuit may not match that of a dedicated watchdog circuit, but this circuit is helpful when the only watchdog in the lab doesn’t meet your design’s temperature requirement and when you are in a hurry to finish a prototype...
Comparator has independent trip voltages
For an inverting amplifier with hysteresis, resistors RA, RB, and RF determine the crossover voltages. Unfortunately, using three resistors to set the upper and lower trip voltages creates a dependence between the two trip voltages: It’s impossible to set one voltage without affecting the other...
