A
hand held, portable jump
starter device, comprising: a housing having a multi-
cell rechargeable battery including at least three battery cells connected in series, a
USB input port for receiving a charging current from an
external source to recharge the multi-
cell rechargeable battery, and an output port for providing jump starting current to an external vehicle; a
USB charge circuit connected to the
USB input port, the USB charge circuit including a DC-to-
DC converter circuit for upconverting an input
voltage on the USB input port to a higher charging
voltage for recharging the multi-
cell rechargeable battery, and a pair of series connected
transistor devices coupled between the DC-to-
DC converter circuit and the multi- cell rechargeable battery for controlling current flow into and out of the multi-cell rechargeable battery; a
control circuit for detecting the
voltage of the multi-cell rechargeable battery and configured to turn off the USB charge circuit to prevent over charging of the multi-cell rechargeable battery if the detected voltage exceeds a threshold value; and a
battery charge controller coupled to the multi- cell rechargeable battery and the pair of series connected
transistor devices and configured to prevent over discharging of the multi-cell rechargeable battery. 21281751_1 (GHMatters) P41255AU03.6 20 24 26 69 04 26 N ov 2 02 4 A B S T R A C T 2 0 2 4 2 6 6 9 0 4 2 6 N o v 2 0 2 4