LM317 fans will recognize Figure as the traditional LM317 constant current source topology...
PWM-programmed LM317 constant current source
Test technique quantifies jitter of discrete-comparator design
A colleague asked for the measured jitter number on a single-supply comparator design based on the LM359 IC. He wanted to know how the jitter performance of the discrete comparator compared to an IC comparator, which was used with an ultrasound application...
Infrared (IR) receiver circuit minimizes power consumption
Receiving infrared signals while conserving system power is difficult, and typically requires the inclusion of complex power-management routines in the firmware. You can avoid that problem by disconnecting power to the microcontroller when IR is not present...
Photo tachometer sensor accommodates ambient light
Tachometry, the measurement of the speed of spin of rotating objects, is a common application. Some of those objects, however, have quirky aspects that make them extra interesting, even scary...
Reduce EMI by sweeping a power supply's frequency
Switching power supplies can be notorious noise generators. You should prevent this noise, which is conducted, radiated, or both, from returning to the input source...
Infineon CoolGaN power transistors enable SounDigital to reach higher fidelity in smaller amplifier systems
Manufacturers of cutting-edge audio equipment constantly seek to enhance sound quality while also meeting the growing demand for compact, lightweight, more integrated, and energy-efficient designs...
Water-leak detector uses 9V batteries
A previously published Design Idea describes a practical gadget that has the potential to save a lot with little investment. However, the circuit uses 120 V line voltage and, as such, it is not that convenient for many applications...
White-LED driver provides 64-step logarithmic dimming
The circuit is designed for portable-power applications that require white LEDs with adjustable, logarithmic dimming levels. The circuit drives as many as four white LEDs from a 3.3 V source and adjusts the total LED current from 1 to 106 mA in 64 steps of 1 dB each...
Need an extra ADC? Add one for a few cents
When designing devices with microcontrollers, I like to use some of the analog-to-digital converter inputs to measure onboard voltages along with all the required sensors inputs. This means I often run out of ADC inputs...
A novel approach to creating a high-efficiency, simple buck-boost converter
A stable voltage from an input supply that is higher and lower than the output is often required. A common solution is to use a boost converter followed by an LDO...
