The circuit uses a typical technique for varying the output voltage of a power supply via a programmable control voltage. Although the topology and schematic details of the power supply are not critical, the protection technique is novel...
Shunt regulator provides overvoltage protection
Generate a pulse width that is inversely proportional to the square root of an analog voltage
The circuit is an edge-triggered monostable circuit, based on a previous design of an edge-triggered parabolic-pulse generator...
Positive edges trigger parabolic timebase generator
Nonlinear systems often need to become linear to be useful, and the circuit provides a nonlinear sawtooth pulse for a PWM (pulse-width modulator) that can compensate for nonlinearities in sensors, controllers, or systems...
Memory-termination IC balances charges on series capacitors
As one of today's most interesting component families, high-value capacitors offer ratings ranging from tenths to tens of farads but suffer from relatively low working voltages...
Transconductance amp gives oscillator reciprocal response
The circuit is a variation on the familiar integrator/comparator triangle-wave oscillator, which you typically implement with two op amps. An integrator and a comparator connect in a positive-feedback loop; the comparator drives the integrator and vice versa...
Novel Switch Interface Scheme Reduces Microprocessor Pin Count
The most common method for interfacing multiple switches – multiplexing – allows for the connection of (N/2)2 switches with N microcontroller I/O lines. The method described below, which has its roots in an LED interface technique commonly known as “Charlieplexing,” makes it possible to interface...
Dynamic-load circuit determines a battery's internal resistance
The simplest model of a battery comprises an ideal voltage source that connects in series with a resistance whose value – often a few milliohms – depends on the battery's electrochemical condition and construction. If you attempt to use an ordinary ac milliohmmeter containing a kilohertz-range ac excitation source to measure a battery's internal resistance, you get erroneous results...
Switched-gain op amp serves as phase detector or mixer
Some op amps, such as the AD8041 from Analog Devices and the EL5100 from Intersil, provide a disable pin, which allows you to parallel the outputs of several op amps for video multiplexing. In addition to this multiplexing, you can also use the disable function...
Simple Super Ripple-Eater Also Cleans Battery-Based Supply
Many amplifiers, including integrated devices, are afflicted with undesired, implicit input terminals in their power connections. Due to less than perfect power-supply rejection, these implicit terminals admit noise into the signal that the amplifier will magnify...
RF oscillator uses current-feedback op amp
A current-feedback amplifier is a well-known component with many uses. Its basic block diagram shows that its input stage is a voltage follower – in practice, a symmetrical emitter follower...
