Patent ID: 7728556

Claim:
A semiconductor device for protecting a rechargeable cell at least from excessive discharge current due to over discharge of the rechargeable cell, the semiconductor device comprising: a first excessive discharge current detection circuit configured to detect first excess of a voltage at an electric current detection terminal exceeding a first voltage level, the electric current detection terminal converting a discharge current to a positive voltage with respect to a ground potential; a second excessive discharge current detection circuit configured to detect second excess of an absolute voltage at the electric current detection terminal exceeding a second voltage level higher than the first voltage level; a delay circuit configured to delay output of each of the first and second excessive discharge current detection circuits by a corresponding delay time; and a delay reducing circuit configured to reduce the delay time by a predetermined ratio by generating a delay time reducing signal in response to a detection of a condition that a negative voltage lower than a predetermined negative voltage level or a positive voltage higher than a third voltage level is applied to the electric current detection terminal, and to maintain the delay time without any change, in a case of absence of the detection of the condition, wherein upon receiving the delay time reducing signal, the delay circuit changes the delay time by a first reducing ratio in a recharging mode, and changes the delay time by a second reducing ratio in a discharging mode, the first reducing ratio being different from the second reducing ratio.