Method and apparatus for optimizing battery cell utilization in a portable communication device

A method for managing power in a battery pack for a portable radio device, the method comprising:

• within the battery pack:
• applying a voltage supply signal from a Li-ion multi-cell battery pack to an input of a DC-DC converter, the voltage supply signal being supplied from a headroom voltage, the headroom voltage being above a predetermined level of a normal operating voltage of the battery pack;
• converting the applied voltage supply signal to a reduced voltage with same power output at an output of the DC-DC converter;
• comparing, using an overvoltage protection circuit, the reduced voltage to a predetermined overvoltage threshold;
• and
• in response to not exceeding the predetermined overvoltage protection threshold, providing the reduced voltage and constant power to a supply contact (B+) of the multi-cell battery pack for supplying voltage and sourcing current to the portable radio device.

A portable radio, comprising:

• a radio portion providing converged communications over land mobile radio (LMR) and broadband;
• a battery pack for powering the radio portion, the battery pack comprising:
• an internal cell stack of Li-Ion cells characterized by a linear output voltage curve with an internal cell stack voltage that is higher than an operational voltage of the portable radio;
• and
• a DC-DC converter applied to the an internal cell stack voltage, the DC-DC converter converting the internal cell stack voltage to a desired DC-DC converter output voltage, the internal cell stack voltage providing headroom for operation of the DC-DC converter.