Patent ID: 7710098

Claim:
A high-side driver circuit for a switching power supply, the power supply having a switching control system operating from a first voltage supply and a power switching device configured to switch a second voltage supply higher than said first voltage supply, said first voltage supply having a first ground rail, said power switching device having a switching control connection for controlling switching of said second voltage supply, said high-side driver circuit being configured to translate a low-side switching control signal from said switching control system and referenced to said first ground rail to a high-side switching control signal referenced to a second, high-side ground rail for driving said switching control connection of said power switching device, said low-side switching control signal comprising a first signal for switching said power switching device on and a second signal for switching said power switching device off, said high-side driver circuit comprising: first and second inputs to receive said first and second low-side switching control signals; a differential amplifier having a differential pair of inputs coupled to said first and second inputs and having an output, said differential amplifier having a ground connection for connection to said high-side ground rail and a power connection to receive a power supply from said second voltage supply, wherein said differential amplifier has a pair of output arms comprising respective first and second transistors each connected as a resistive load; an output coupled to said differential amplifier output to provide said high-side switching control signal; and a current mirror, wherein said differential amplifier has a tail current set by said current mirror, wherein an input current to said current mirror is set by a third transistor connected as a resistor, and wherein control connections of said first, second and third transistors are coupled to a common voltage supply.