DC-DC converter circuit

A power supply, comprising:

• an output node;
• a circuit node configured to receive an interference signal having a first frequency;
• a converter circuit configured to generate a regulated output signal at the output node and to switch at a second frequency;
• and
• a feedback circuit coupled to the output node and to the converter circuit and configured to generate a compensation signal having a third frequency that is approximately equal to a difference between the first and second frequencies;
• wherein the feedback circuit comprises:
• an operational amplifier having an input node and an output node;
• a first capacitor coupled between the input and output nodes;
• a resistor and second capacitor serially coupled between the input and output nodes;
• and
• a third capacitor coupled in electrical parallel with the resistor.

A system, comprising:

• a power supply, including:
• an output node;
• a circuit node configured to receive an interference signal having a first frequency;
• a converter circuit configured to generate a regulated output signal at the output node and to switch at a second frequency;
• and
• a feedback circuit coupled to the output node and to the converter circuit and configured to generate a compensation signal having a third frequency that is approximately equal to a difference between the first and second frequencies;
• and
• a load coupled to the output node.

A method, comprising:

• generating a regulated output signal at an output node by coupling a first input signal to the output node at a first frequency and at a duty cycle;
• receiving an interference signal having a second frequency;
• and
• compensating the regulated output signal at a third frequency that is approximately equal to a difference between the first and second frequencies.