Low voltage battery pack monitoring circuit with adjustable set points

A battery pack monitoring circuit for a portable electronic device having a battery pack, electronic circuitry including a microprocessor and a plurality of electronic systems, the monitoring circuit comprising:

• a) a first comparison circuit for comparing a low battery pack set point voltage value to an output voltage across the battery pack and generating a signal resulting in actuation of a low battery indicator upon the battery pack output voltage falling below the low battery set point voltage value;
• b) a second comparison circuit including a power failure comparator having an output with two output states, the comparator electrically coupled to the battery pack for comparing a power failure set point voltage value to the output voltage across the battery pack, the comparator output changing from a first output state to a second output state upon the battery pack output voltage falling below the power failure set point voltage value, at least one of the electronic systems of the device coupled to the output of the comparator and being turned off upon the comparator output changing to the second output state;
• and
• c) the second comparison circuit including a D flip-flop and a switch coupled between the output of the power failure comparator and the at least one of the electronic systems of the device, an output of the D flip-flop changing state when the power failure comparator changes from the first output state to second output state causing the switch to change state and turn off the at least one of the electronic systems.

A battery pack monitoring circuit for a portable electronic device having a battery pack electronic circuitry including a microprocessor and a plurality of electronic systems, the monitoring circuit comprising:

• a) a first comparison circuit for comparing a low battery pack set point voltage value to an output voltage across the battery pack and generating a signal resulting in actuation of a low battery indicator upon the battery pack output voltage falling below the low battery set point voltage value;
• b) a second comparison circuit including a power failure comparator having an output with two output states, the comparator electrically coupled to the battery pack for comparing a power failure set point voltage value to the output voltage across the battery pack, the comparator output chanting from a first output state to a second output state upon the battery pack output voltage falling below the power failure set point voltage value, at least one of the electronic systems of the device coupled to the output of the comparator and being turned off upon the comparator output changing to the second output state;
• and
• c) the low battery pack set point voltage value and the power failure set point voltage value being determined from an empirical look up table.

A battery pack monitoring circuit for a portable electronic device having a battery pack, electronic circuitry including a microprocessor and a plurality of electronic systems, the monitoring circuit comprising:

• a) a power failure comparison circuit including a power failure comparator having an output and being electrically coupled to the battery pack for comparing a power failure set point voltage value to the output voltage across the battery pack;
• b) the power failure comparator output changing output states upon the battery pack output voltage falling below the power failure set point voltage value, at least one of the electronic systems of the device coupled to the output of the power failure comparison circuit and being turned off upon the power failure comparator changing output states;
• and
• c) the power failure comparison circuit including a D flip-flop and a switch coupled between the output of the power failure comparator and the at least one of the electronic systems of the device, an output of the D flip-flop changing state when the power failure comparator changes from the first output state to second output state causing the switch to change state and turn off the at least one of the electronic systems.