Multi-cell power system controller

A method for detecting cell connection status of a multi-cell battery, the method comprising:

• converting a voltage across each cell of the multi-cell battery to a current to generate a current-based connection status indicating signal for each of the cells;
• evaluating a current level of each of the current-based connection status indicating signals from a cell connection status detector comprising a bandgap referenced voltage to current converter generating a discreetly-valued current signal having one of an on value and an off value;
• and
• generating a common reference status indicating signal for each of the current-based connection status indicating signals based on the current levels, wherein the common reference status indicating signals are referenced to a same voltage level and wherein each cell of the multi-cell battery is referenced to a different voltage level.

An apparatus for detecting cell connection status of a multi-cell battery, the apparatus comprising:

• a plurality of battery cell inputs;
• a plurality of cell connection status detectors, each connected to a battery cell input, each of the plurality of cell connection status detectors having a current-based status indicator output, wherein each of the plurality of cell connection status detectors comprises a bandgap referenced voltage to current converter generating a discretely-valued current signal having one of an on value and an off value, the bandgap referenced voltage to current converter connected between a positive terminal and a negative terminal, which comprise adjacent ones of the plurality of battery cell inputs;
• and
• at least one comparator connected to the plurality of current-based status indicator outputs, wherein each of the plurality of cell connection status detectors floats in a different supply voltage range, and wherein the at least one comparator is referenced to a lower voltage potential than at least one of the plurality of cell connection status detectors, wherein each of the plurality of cell connection status detectors comprises:
• a switchable voltage divider connected across the cell, the switchable voltage divider being adapted to switch between a first resistance and a second resistance at an output of the switchable voltage divider, wherein each of the plurality of cell connection status detectors is adapted to detect an overvoltage condition at the associated one of the battery cell inputs when the switchable voltage divider is switched to the first resistance and to detect an undervoltage condition when the switchable voltage divider is switched to the second resistance;
• a first diode-connected P-channel transistor connected to the positive terminal;
• a first NPN BJT transistor connected to the diode connected P-channel transistor, the first NPN BJT transistor having a base connected to the voltage divider;
• a second P-channel transistor connected to the positive terminal, wherein a gate of the second P-channel transistor is connected to a gate of the first diode-connected P-channel transistor;
• and
• a second NPN BJT transistor connected to the second P-channel transistor, wherein a base of the second NPN BJT transistor is connected to the base of the first NPN BJT transistor, and wherein an emitter of the second NPN BJT transistor is connected to an emitter of the first NPN BJT transistor through a second voltage divider.