Patent ID: 6703810
Filing Date: 2004-03-09
Classification: H02M

Abstract:
A circuit for regulating the charge current with improved loop stability, comprising:means to provide the supply voltage to draw the charging current from; means to regulate a charging current, operating as an electric current valve; a shunt resistor to produce a voltage proportional to said charge current; means to build an adjustable voltage source, which, divided by said shunt resistor, represents the desired charge current; means to compare said voltage proportional to said charge current and said reference voltage proportional to said desired charge current, determining whether said charge current is, at a given time, above or below its desired value; means for an up/down counter that increases or decreases its counter value, depending on the above voltage comparisons result; an oscillator to step said up/down counter in a regular time interval; means to enable and disable said oscillator; means building a digital-to-analog-converter, converting the digital output value of said means for an up/down counter into an analog signal, which will control the current regulating element; means to control said current regulating element depending on the analog output current of said means building a digital-to-analog-converter means to enable or disable the current regulating element; and means to sense the minimum supply voltage, in order to control enable or disable the regulator operation.