Patent ID: 7948727
Filing Date: 2011-05-24
Classification: H02J

Abstract:
1. An over-voltage protection circuit for connection to a charging circuit for maintaining a voltage across a plurality of electrical energy storage devices at or below a predetermined voltage during charging, comprising: a first electrical energy storage device connected from a top voltage rail to a primary junction; a second electrical energy storage device connected from the primary junction to a bottom voltage rail, the first electrical energy storage device and the second electrical energy storage device charged by current flowing from the top rail through the first electrical energy storage device and the second electrical energy storage device to the bottom rail; an inductor; and a first switch and a second switch; the over-voltage protection circuit to perform a first procedure in which a charge is drawn from the first electrical energy storage device through the inductor to energize the inductor, the inductor then to cause a current that charges the second storage device, the first procedure beginning when the first switch is closed; the over-voltage protection circuit to perform a second procedure in which a charge is drawn from the second electrical energy storage device through the inductor to energize the inductor, the inductor then to cause a current that charges the first storage device, the second procedure beginning when the second switch is closed; the inductor to be energized to less than saturation level; a voltage sensor, the voltage sensor to close the first switch in response to the first electrical energy storage device being excessively charged and to close the second switch in response to the second electrical energy storage device being excessively charged; and a dissipation controller to perform a third procedure in which a charge is discharged from the energized inductor upon detection of an over-voltage condition by the voltage sensor.