Patent ID: 9065337
Filing Date: 2015-06-23
Classification: H02M

Abstract:
1. An inductor current emulation circuit for use with a switching converter arranged to operate high and low side switching elements connected to an output inductor using a switching cycle having an associated ‘on’ time and ‘off’ time to produce an output voltage, in which regulation of said output voltage includes comparing an output which varies with the difference between said output voltage and a reference voltage with a ‘ramp’ signal which emulates the current in said converter's output inductor, said emulation circuit comprising: a current sensing circuit arranged to produce an output which varies with the current in the switching element that is turned on during said ‘off’ time, wherein said current sensing circuit senses the current in said low side switching element when said switching converter is configured as a buck converter, and senses the current in said high side switching element when said switching converter is configured as a boost converter; an emulated current generator circuit arranged to produce said ‘ramp’ signal such that it emulates the current in said converter's output inductor during said ‘off’ and ‘on’ times and which varies said ‘ramp’ signal in response to a control signal; a comparator circuit arranged to, during a portion of said ‘off’ time, compare said ‘ramp’ signal with at least one threshold voltage that varies with said current sensing circuit output, and to toggle an output when said ‘ramp’ signal exceeds said at least one threshold voltage; and a feedback circuit which provides said control signal to said emulated current generator and is arranged to vary said control signal each time said comparator circuit output toggles until said ‘ramp’ signal no longer exceeds said at least one threshold voltage.