Patent ID: 8866453

Claim:
A Buck switching regulator, comprising: first Buck switching regulator circuitry operable in response to a second output voltage to generate a first output voltage from an input voltage and operable to generate a first sensed voltage having a value that is proportional to an output current being provided by the first Buck switching regulator circuitry, and the first Buck switching regulator circuitry receiving an input current and operating at a first duty cycle determined by a duty cycle signal; and input current sensing circuitry including second Buck switching regulator circuitry coupled to the first Buck regulator switching circuitry to receive the duty cycle signal and to receive the first sensed voltage as an input voltage to the second Buck switching regulator circuitry, the second Buck switching regulator circuitry operable responsive to the duty cycle signal to generate the second output voltage from the first sensed voltage, the second output voltage having a value that is proportional to the input current being supplied to the first Buck switching regulator circuitry.