Switched mode power supply controller circuit and method thereof

A regulator circuit for regulating a power supply, comprising:

• a switching regulator circuit coupled to a feedback terminal at a first pin of the regulator circuit for receiving a feedback signal which controls the switching regulator circuit to provide a regulator output signal;
• and
• a Vcc limiter coupled to a first power supply terminal at a second pin of the regulator circuit for receiving an operating voltage, wherein the Vcc limiter regulates the operating voltage at the first power supply terminal and at a portion of the switching regulator circuit, the Vcc limiter including,
• (a) a transistor pair having a first control terminal coupled to receive a reference signal and a second control terminal coupled to receive a signal indicative of the operating voltage and coupled to provide a control signal;
• and
• (b) a current mirror having a first conduction terminal coupled to receive the control signal and a second conduction terminal coupled to the first power supply terminal.

A method of regulating a power supply for an integrated circuit, comprising:

• receiving a feedback signal at a feedback terminal of the integrated circuit;
• controlling the integrated circuit with the feedback signal to provide a regulator output signal;
• receiving an operating voltage at a first power supply terminal of the integrated circuit;
• decreasing the operating voltage if the operating voltage is detected as increasing;
• and
• increasing the operating voltage if the operating voltage is detected as decreasing.