Differential difference amplifier for amplifying small signals close to zero volts

A battery monitoring apparatus comprising:

• a sensor coupled to a battery such that a charge current flows through said sensor when said battery is charging and a discharge current flows through said sensor when said battery is discharging;
• an offset voltage generation circuit capable of generating an offset voltage;
• a differential difference amplifier for amplifying a voltage sense signal on said sense resistor and adding said offset voltage to the amplified voltage sense signal, said differential difference amplifier comprising:
• at least two differential transistor pairs;
• at least two cascode transistor pairs, wherein each cascode transistor is coupled in series with a corresponding differential transistor;
• and
• current difference detection circuitry that operates to (i) detect a current difference between a first composite current generated by a first at least two series pairs of transistors and a second composite current generated by a second at least two series pairs of transistors, and (ii) generate an output voltage proportional to said current difference;
• and
• an analog-to-digital converter coupled to an output of said differential difference amplifier that converts said amplified voltage sense signal and said offset signal to a digital signal readable by circuitry associated with said ADC.