Patent ID: 7898321

Claim:
An apparatus comprising: a current source that is adapted to provide a reference current; a current mirror that is coupled to the current source; a first transistor that is coupled to the current mirror; an amplifier having a first input, a second input, and an output, wherein the first input of the amplifier is coupled to the current mirror, and wherein the second input of the amplifier is coupled to a node between the first transistor and the current mirror, and wherein the output of the amplifier is coupled to the control electrode of the first transistor; and a presetting circuit that is coupled to the control electrode of the first transistor, wherein the presetting circuit presets the potential of the control electrode of the first transistor to a level that allows current driving of the transistor with a predetermined timing after a control signal is received, wherein the presetting circuit includes: a delay circuit that is adapted to receive the control signal; logic that is coupled to the delay circuit; a current generating circuit that is coupled to the logic; and a second transistor that is coupled between the current generating circuit and the control electrode of the first transistor and that is coupled the logic at its control electrode.