Method and apparatus for providing adaptive inductor peak current in DC-DC converter

A method comprising:

• receiving, on a first terminal of an inductor in a DC-DC converter, an input voltage from an input voltage source;
• activating and deactivating, using a control circuit, a transistor coupled to a second terminal of the inductor;
• operating the control circuit in a first mode based on a feedback signal and a first reference voltage, wherein operating the control circuit in the first mode comprises activating and deactivating the transistor using pulse frequency modulation (PFM) such that a peak-to-peak current through the inductor has a fixed value;
• and
• operating the control circuit in a second mode based on the feedback signal, the first reference voltage, and a second reference voltage that is less than the first reference voltage, wherein operating the control circuit in the second mode comprises activating and deactivating the transistor using PFM and pulse width modulation (PWM) such that the peak-to-peak current through the inductor is modulated to meet a current demanded by a load circuit coupled to receive an output voltage generated by the DC-DC converter, wherein operating in the second mode comprises the control circuit causing an increase of the peak-to-peak current through the inductor based on an amount of time a voltage of the feedback signal is less than the second reference voltage.

An apparatus comprising:

• a load circuit coupled to receive a supply voltage;
• and
• a DC-DC converter configured to generate the supply voltage including:
• an inductor coupled to receive an input voltage on a first terminal;
• a transistor having a drain terminal coupled to a second terminal of the inductor;
• and
• a control circuit configured to control selectively activate and deactivate the transistor in accordance with operation in a first mode and a second mode, wherein, during operation in the first mode, the control circuit is configured to, based on a first threshold voltage, activate and deactivate the transistor such that pulses of current through the inductor have a fixed width and a fixed peak-to-peak value, and wherein during operation in the second mode, the control circuit is configured to, based on a second threshold voltage less than the first threshold voltage, activate and deactivate the transistor such that pulses of current through the inductor have a variable width and a variable amplitude and further configured to cause an increase of the peak-to-peak current through the inductor based on an amount of time a feedback voltage is less than the second threshold voltage.