Apple Inc.
Systems and methods for sensing current in a power converter

Abstract:

Systems, apparatuses, and methods for efficiently generating a stable output voltage for one or more components are described. In various embodiments, current sensing circuitry within a power converter includes one or more current mirrors in addition to at least a first resistor, a second resistor, a switch and a bias current source. The sizes of these latter components scales the sensing current output of the current sensing circuitry from a value of an inductor current flowing through the low pass filter output of the power converter. In addition, the sizes generate an offset which maintains the sensing current as a positive value even when the inductor current becomes a negative value. The boosted sensing current makes a zero detection function and a protection function for the power converter relatively simple with current comparisons.