Regulator Loss Cutter Circuit

Posted on Mar 19, 2013

Large input-to-output voltage differentials, caused by wide input voltage variations, reduce a linear regulator`s efficiency and increase its power dissipation. A switching preregulator can reduce this power dissipation by minimizing the voltage drop across an adjustable linear regulator to a constant 1.5-V value. The circuit operates the LT1084 at slightly above its dropout voltage. To minimize power dissipation, a low-dropout linear regulator was chosen. The LT1084 functions as a conventional adjustable linear regulator with an output voltage that can be varied from 1.25 to 30 V.

Regulator Loss Cutter Circuit
Click here to download the full size of the above Circuit.

Without the preregulator (for a 40-V input and a 5-V output at 5 A), it would be virtually impossible to find a heatsink large enough to dissipate enough energy to keep the linear-regulator junction temperature below its maximum value. With the preregulator technique, however, the linear regulator will dissipate only 7.5 W under worst-case loading conditions for the entire input- voltage range of 15 to 40 V. Even under a short-circuit fault condition, the 1.5-V drop across the LT1084 is maintained.

Leave Comment

characters left:

New Circuits



Popular Circuits

Temperature-to-frequency converter
Remote Field Strength Meter Circuit
Frequency to voltage converter
ac Trouble with triac driven dimmer circuit
Laser Activated Switch
walter duo
Guitar pre-amplifier using uA 741
weather car wont start and radio keyless entry power windows
Sound Alarm Circuit
Sinusoidal Oscillators
Bright light control circuit diagram of a precision