Apparatus for regulating a bias-voltage of a switching power supply

An apparatus for regulating a bias-voltage of a switching power supply, the apparatus comprising:

• a cascode amplifier having a common-gate transistor and a common-source transistor, wherein a source of the common-gate transistor is in signal communication with a drain of the common-source transistor;
• a feedback-circuit in signal communication with the source of the common-gate transistor and the drain of the common-source transistor, wherein the feedback-circuit is configured to receive a drain-voltage from the drain of the common-source transistor and produce a first feedback-voltage and a second feedback-voltage using the drain-voltage, the first feedback-voltage having a first voltage level and the second feedback-voltage having a second voltage level;
• and
• a bias-regulator circuit in signal communication with a gate of the common-source transistor, a gate of the common-gate transistor, and the feedback-circuit,
• wherein the bias-regulator circuit is configured to receive the first feedback-voltage and the second feedback-voltage and produce and regulate the bias-voltage using the first feedback-voltage and the second feedback-voltage,
• wherein a gate-voltage is produced from the bias-voltage, and
• wherein the gate-voltage is injected into the gate of the common-gate transistor.