Patent ID: 8675320

Claim:
An overcurrent detection circuit for a DC-to-DC power converter, comprising: a dynamic reference unit for outputting a dynamic reference signal, and including: a first resistor having a resistance; a reference current source for generating a reference current; a first transistor including a gate coupled to a ground, a source coupled to a system voltage, and a drain coupled to the reference current source, the reference current flows through the first transistor to generate a cross voltage of the first transistor; and a first operational amplifier including: a negative input terminal coupled to the source of the first transistor; a positive input terminal coupled to the drain of the first transistor; and an output terminal coupled to the first resistor and the negative input terminal of the first comparator for outputting the dynamic reference signal to the negative input terminal of the first comparator according to the cross voltage of the first transistor, a conductance of the first operational amplifier and the resistance of the first resistor; a load current measurement unit for measuring a load current of the DC-to-DC power converter to output a measurement signal; and a first comparator including a positive input terminal coupled to the load current measurement unit, a negative input terminal coupled to the dynamic reference unit and an output terminal coupled to an overcurrent protection device for outputting an overcurrent protection signal to activate the overcurrent protection device when the measurement signal is greater than the dynamic reference signal.