Patent ID: 9083181
Filing Date: 2015-07-14
Classification: H02H

Abstract:
1. An overcurrent protection circuit for a light source driving module, the light source driving module comprising a power module, the power module comprising a switch and a detection resistor, a first end of the switch electrically connected to a first end of the detection resistor, a second end of the detection resistor electrically connected to ground, the overcurrent protection circuit comprising: a peak value overcurrent protection module, for detecting a voltage at a node where the switch and the detection resistor are connected and generating a turning-off signal to turn off the switch when the voltage is larger or equal to a threshold voltage, wherein the voltage is formed by a current of the switch; and an average value overcurrent protection module, performing a logic AND operation with the peak value overcurrent protection module, for detecting an average voltage at the node and generating the turning-off signal to turn off the switch when the average voltage is larger or equal to a threshold average voltage, wherein the average voltage is formed by an average current of the switch, and the average voltage is an average value of the voltage within one or more switching periods; wherein the overcurrent protection circuit further comprises a first logic AND arithmetic unit, and the peak value overcurrent protection module comprises a peak value comparing unit and a second logic AND arithmetic unit; wherein the peak value comparing unit compares the voltage with the threshold voltage; wherein if the voltage is larger than or equal to the threshold voltage, the turning-off signal is generated by the peak value comparing unit; wherein the second logic AND arithmetic unit receives a driving signal and a signal generated by the peak value comparing unit; wherein if the driving signal or the signal generated by the peak value comparing unit corresponds to the turning-off signal, then the turning-off signal is generated by the second logic AND arithmetic unit; wherein the first logic AND arithmetic unit receives signals generated by the average value overcurrent protection module and the peak value overcurrent protection module; if one of the signals generated by the average value overcurrent protection module and the peak value overcurrent protection module corresponds to the turning-off signal, then the first logic AND arithmetic unit generates the turning-off signal to a control end of the switch to turn off the switch.