Inductor current emulation circuit for a switching converter

摘要

An inductor current emulation circuit for use with a switching converter configured to provide high and low side switching elements connected to an output inductor using a switching cycle having an associated "on" phase and "off" phase to produce a switching inductor Operating output voltage, wherein the regulation of the output voltage comprises comparing an output signal which varies with the difference between the output voltage and a reference voltage, with a "ramp" signal which emulates the current in the output inductor of the converter, the emulation circuit comprising A current sense circuit configured to generate an output signal that varies with the current in the switching element that is turned on during the "off" phase, wherein the current sense circuit detects the current in the low-side switching element when the switching converter as Down converter is formed, and erfa the current in the high-side switching element sst, when the switching converter is designed as a step-up converter; an emulation current generation circuit configured to generate the "ramp" signal to emulate the current in the output inductor of the transducer during the "off" and "on" phases and the "ramp" signal in response to a Control signal varies; a comparison circuit adapted to compare, during a portion of the "off" phase, the "ramp" signal with at least one threshold voltage that varies with the output of the current measuring circuit, and to switch an output when the "ramp" Signal exceeding at least one threshold voltage; and a feedback circuit that provides the control signal to the emulation power generation circuit and is configured to vary the control signal each time the output of the comparison circuit switches until the ramp signal no longer exceeds the at least one threshold voltage.