Direct digital synthesis ICs can convert square waves to sine/cosine waves but their complexity is a disadvantage. This circuit uses simple CMOS logic and two switched-capacitor filters to perform the conversion....More
Capacitors are used in parallel to provide special performance attributes; however, it's difficult to determine critical performance specifics of ESR, high-frequency ripple voltage, and individual RMS currents when they have unequal values. This numerical approach provides a straightforward solution to calculating the values based on published specifications....More
The nonlinear relationship between forward voltage and current in an LED makes it difficult to properly size the drive current and current-limiting resistor, but useful analysis can be derived from the exponential diode model....More
A charge pump (or Q pump) uses a flying-capacitor architecture to boost a single cell's voltage to a regulated 2.5V, yet operates at low quiescent current. This approach is a good fit for microcontroller applications where the load is usually in sleep mode and quiescent battery drain is more important than efficiency at higher loads. The two-stage design has efficiency in the 40 to 70% range—comparable to an LDO—yet consumes just microamps when the load is not active....More
This circuit uses a standard hex inverter to create an oscillator and Class-D amplifier, which in turn drives MOSFETs that can efficiently supply the bipolar rails and sink the ground current....More
By modeling and analyzing your switching or linear voltage regulator, you can properly size the hold-up capacitor to support the circuit load during line-cycle drops after the rectification stage...More
This article presents apples-to-apples test results for noise densities for several low-noise discrete, SMT n-JFETs. The tests used the same operating conditions so that designers can make a fair comparison for their applications....More
This article presents apples-to-apples test results for noise densities for several low-noise discrete, SMT n-JFETs. The tests used the same operating conditions so that designers can make a fair comparison for their applications....More
This circuit solves the problem of sending data over a cable with no free conductors. The data is OOK (on-off keying) modulated and superimposed on a high-frequency carrier so it can be sent over a low-voltage power supply line....More
This circuit uses a microcontroller and simple algorithm managing voltage regulator ICs and discrete components to control charging of nickel-cadmium batteries. It provides a steady charging current matched to the battery capacity while avoiding overcharging; it also includes LEDs that indicate the status of the charging process to the user....More
