Micropower switch controller for use in a hysteretic current-mode switching regulator

摘要

A micropower switching regulator for use in a hysteretic current- mode switching mode power converter monitors a fraction of the voltage output to the load in order to maintain the output voltage at a desired level. When the output voltage is less than the desired level, a proportional current is generated, representative of the difference between the output voltage and the desired level, and used to control the switching regulator causing an inductor to alternate between charging to a hysteretic maximum current level and then discharging to a hysteretic minimum current level, controlled by the switching regulator, until the output voltage is greater than the desired level. The hysteretic maximum and minimum current levels vary as the proportional current varies, so that as the difference between the output voltage and the desired voltage increases or decreases, the current level in the inductor will also increase or decrease, responsively. The inductor is charged and discharged continuously during a continuous conduction mode. During a discontinuous conduction or idle mode, the switching regulator is only turned on when necessary to maintain the output voltage at a level equal to or greater than the desired voltage level. Power is only drawn by the switching regulator, from the input source, when the proportional current is generated, because there is a difference between the output voltage and the desired voltage. In this manner the power provided by the input source is conserved and the desired output voltage level is maintained efficiently.