Method for computing an amount of energy taken from a battery

DETAILED DESCRIPTION In accordance with one embodiment of the present invention, a method is provided to accurately compute the amount of energy taken from a battery powering a switching power converter circuit.
Unlike the prior art, the method according to one embodiment of the present invention does not rely on a voltage drop across a sense resistor.
Instead, a voltage across a capacitor is sampled over time and the energy taken from the battery is computed.
The method comprises applying one or more control pulses to the switching power converter circuit to establish a voltage on the capacitor to a predetermined voltage.
The voltage on the capacitor is periodically sampled and at least one control pulse is applied to the switching power converter circuit to raise the voltage to the predetermined voltage.
The amount of energy taken from the battery is computed based on a measured voltage change and a time elapsed.
This invention will be more fully understood in conjunction with the drawings taken together with the following detailed description.