Circuits and methods for controlling a switching regulator based on a derived input current

An apparatus comprising:

• a switching regulator, the switching regulator generating a switching signal;
• an output current sense circuit coupled to receive an output current of the switching regulator into a load, and in accordance therewith, generate a first signal representing a value of the output current of the switching regulator into the load;
• a duty cycle measurement circuit coupled to receive the switching signal, and in accordance therewith, generate a second signal representing a value of the duty cycle of the switching signal;
• and
• a control circuit comprising a multiplier circuit coupled to receive the first signal and second signal and combine the first signal and second signal to produce a third signal representing a value of an input current of said switching regulator, wherein the first signal is proportional to the output current and the second signal is proportional to the duty cycle, and wherein the multiplier circuit multiplies the first signal and second signal to generate the third signal that is proportional to the input current, the control circuit further comprising a divider circuit coupled to an output of the multiplier circuit, the divider circuit receiving the third signal and a fourth signal representing a value of a supply voltage to produce a fifth signal to modify the switching signal,
• wherein the fifth signal is coupled to a control terminal of the switching regulator to modify the switching signal.

An apparatus comprising:

• a switching regulator, the switching regulator generating a switching signal;
• means for sensing an output current of the switching regulator into a load and for generating a first signal representing a value of the output current of the switching regulator into the load;
• and
• means for determining a duty cycle of the switching signal coupled to receive the switching signal and for generating a second signal representing a value of the duty cycle of the switching signal;
• means for generating a fourth signal representing a value of a reference voltage;
• a multiplier circuit to combine the first signal and second signal;
• and
• a divider circuit to combine an output of the multiplier circuit with the fourth signal to produce a third signal representing a value of an input current of said switching regulator,
• wherein the third signal representing the value of the input current is coupled to a control loop of the switching regulator to modify the switching signal.