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Maxim > Design Support > Technical Documents > Application Notes > A/D and D/A Conversion/Sampling Circuits > APP 298

Maxim > Design Support > Technical Documents > Application Notes > Power-Supply Circuits > APP 298

Keywords: current limited, current-limit, switch, digital potentiometer, digital pots, P channel switch,

switches

APPLICATION NOTE 298

Current-Limit Switch Is Digitally Programmable

Aug 17, 2000

Abstract: Current-limit switches are virtually ubiquitous in system controls. They provide a safe means

for regulating the current delivered to a load circuit. The switches allow the load current to increase to a

Technical Support: Power

Current-limit switches are virtually ubiquitous in system controls. They provide a safe means for

regulating the current delivered to a load circuit. The switches allow the load current to increase to a

programmed limit but no higher. Typically, the current limit is a function of the voltage across an external

resistor, produced by the current from a fixed source internal to the switch IC. This voltage serves as the

reference for an internal current-limiting amplifier. By replacing the resistor with a digital potentiometer,

you can easily program the current limit (see the figure below). IC

1

is a current-limit switch with a

maximum programmable limit of 1A. The limit equals 1380/R

IC