Patent ID: 9225158
Filing Date: 2015-12-29
Classification: H02H

Abstract:
1. An overcurrent protection circuit comprising: a load drive section driving a load; a wire coupled with the load and the load drive section; a current detection section detecting a load current value of an electric current that flows to the load, the current detection section including an AD converter and a current value calculation circuit, the AD converter receiving a detection signal corresponding to the load current value and analog-to-digital converting the detection signal, the current value calculation circuit calculating the load current value from the detection signal converted by the AD converter; an addition and subtraction section determining an addition and subtraction value based on the load current value detected by the current detection section, storing an integration result of addition and subtraction using the addition and subtraction value, and transmitting the integration result, the addition and subtraction section including an addition value determination circuit, the addition value determination circuit determining an addition value in the addition and subtraction value based on the load current value calculated by the current value calculation circuit and a function expression or information indicating a relationship between the load current value and the addition value; a comparison circuit comparing the integration result transmitted from the addition and subtraction section with a threshold value and transmitting a signal indicating an overcurrent detection result; and a control circuit controlling the load drive section based on the signal indicating the overcurrent detection result transmitted from the comparison circuit to limit the electric current that flows to the load and the wire and to protect a protection object from an overcurrent, wherein the addition value determination circuit determines the additional value smoothly with respect to the load current value using the function expression, which indicates the relationship between the load current value and the addition value; and does not apparently relate to temperature.