Patent ID: 8174292

Claim:
A current sensing circuit for a pulse width modulation (PWM) application comprising: first and second input terminals to be coupled to ends of a sensing resistance; an output terminal; first and second internal circuit nodes; an input block comprising a first transconductance amplifier to be coupled to a supply voltage, and said first transconductance amplifier coupled to said first and second input terminals and to said first and second internal circuit nodes; an amplifier block comprising an amplifier to be coupled to a reference voltage, and coupled to said first and second internal circuit nodes and said output terminal; and a feedback block comprising a second transconductance amplifier to be coupled to the supply voltage and being coupled to said output terminal and said first and second internal circuit nodes; said input block further comprising a third transconductance amplifier coupled in cascade to said first transconductance amplifier and to said first and second input terminals, said first, second, and third transconductance amplifiers each comprising transistors, the transistors of said third transconductance amplifier operating at a voltage greater than that of the transistors in said first and second transconductance amplifiers.