Patent ID: 7554299
Filing Date: 2009-06-30
Classification: G01R

Abstract:
1. A circuit for monitoring current supplied by a battery, the circuit comprising: a detector including a resistor connected between the battery and a device powered thereby, and including a differential amplifier having inputs connected to terminals of the resistor for providing an output representative of current drawn by the device from the battery, the detector further comprising: a reference resistor selectively connectable to the resistor; a reference voltage; and a switching circuit for selectively supplying the reference voltage to a series connection of the resistor and reference resistor for establishing a reference level of input to the differential amplifier; a voltage-to-frequency converter coupled to receive the output from the detector for generating an output frequency proportional to the received output from the detector; and a processor coupled to receive the output frequency from the voltage-to-frequency converter for producing an output representative of an integral of current over time drawn from the battery.