VOLTAGE REGULATOR HAVING CURRENT AND VOLTAGE FOLDBACK BASED UPON LOAD IMPEDANCE

摘要

The regulated output voltage of a voltage regulator is maintained up to a current limit, Ilimit, then as the load impedance continues to decrease the output current does not increase past the current limit, Ilimit, but rather the output voltage decreases forcing the output current to also decrease to satisfy Ohm's Law: IOUT=VOUT/ZLoad. When the output voltage drops below the regulated voltage value because of current limiting the voltage regulator shifts from a current limit mode to a current foldback mode wherein the output current decreases with the decrease in output voltage until the output current reaches a current foldback minimum, Ifoldback, at an output voltage of substantially zero volts. As the load impedance increases so will the output voltage and current until the output voltage is back at substantially the regulation voltage value, and the output current is less than or equal to the current limit, Ilimit.