Articles - Supply - 5

Every PWM DAC design needs analog filtering to separate the desired PWM duty-cycle-proportional DC component from unwanted AC ripple. The simplest of these is the basic RC low-pass filter, which gives a peak-to-peak ripple amplitude (for the worst ...

Although current mirrors and circuits such as the Howland current source are taught in analog circuit courses, a surprising number of engineers tend to think exclusively in terms of voltage when defining the output of precision analog circuitry. ...

Permanent magnet DC (PMDC) motors offer smaller solution size and increased efficiency in applications such as portable vacuums and cordless electric power tools. When designing an isolated power supply for PMDC motors, there are several ...

The popular and multiply sourced TL431 three-terminal shunt regulator offers designers considerable versatility in its applications. Figure 1a illustrates the TL431’s internal circuitry, which comprises a precision voltage reference, an ...

Many electronics circuits begin operation at voltages below 1.25 V. But popular adjustable regulators such as the LM317 , LM350 , and LM338 can provide output voltages only above 1.25 V, and the L200 minimum is higher at 2.85 V. Fixed-output ...

How do you deliver constant power when the load impedance isn't constant? That problem arises, for example, in trying to maintain a warm LCD display on an outdoor gas pump in cold climates. As the heating element changes temperature, its ...

Audio amplifiers for high-power portable speakers such as trolley speakers usually operate with lithium-ion batteries, and these batteries can vary from a single cell to a few cells in series. Designers generally use boost converters to produce the ...

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 ...

A switched-mode power supply (SMPS) employing peak current-mode control (PCMC) requires a ramp signal to slope-compensate the inner (current) control loop. Slope compensation stabilizes the current loop, which would otherwise exhibit subharmonic ...

Using two unipolar dc supplies in an anti-series configuration is another approach for generating positive and negative voltage and one that doesn't suffer from power interruption. In 2012, I wrote two articles in Electronic Design that ...