Patent ID: 11927642
Assignee: O2MICRO INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC G  H  Y | IPC G  H

Claim 14:
15. A system, comprising:
a plurality of monitoring resistors corresponding to a plurality of cells;
a plurality of capacitors;
a plurality of balance switches;
a plurality of balance resistors, wherein a first cell in said plurality of cells is coupled to a first monitoring resistor of said plurality of monitoring resistors, a second monitoring resistor of said plurality of monitoring resistors, a first capacitor of said plurality of capacitors, a first balance switch of said plurality of balance switches, and a first balance resistor of said plurality of balance resistors:
a control unit coupled to said plurality of balance switches; and
a measure unit, coupled to said control unit and said plurality of capacitors;
wherein said system is configured to execute a method comprising:
(a) generating a first control signal with said control unit, to turn on said first balance switch for a first time period;
(b) generating a second control signal with said control unit, to turn off said first balance switch for a second time period, wherein said second time period follows said first time period;
(c) measuring a voltage value on said first capacitor at the end of said second time period, with said measure unit;
(d) if said voltage value on said first capacitor is less than an open cell threshold, then determining with said control unit that said first cell has an open cell failure;
(e) for each cell of said plurality of cells, repeating steps (a)-(d); and
(f) if at least one cell of said plurality of cells has an open cell failure, then determining, with said control unit, that there is an open cell failure;

wherein said method further comprises:
if there is not an over-temperature situation, then further determining, with said control unit, whether said plurality of cells are being charged;
if said plurality of cells are not being charged, then further determining, with said control unit, whether there is an under-voltage situation;
if there is said under-voltage situation, then further determining, with said control unit, whether it is a first time said under-voltage situation has occurred; and
if it is not the first time, then clearing, with said control unit, an open cell detection timer again.