System and method to boost light load efficiency for multiphase converters
A method for boosting light load efficiency for multiphase converters through disabling at least partially a current sense circuit, disabling partial equivalent elements of one of power stages, using small size equivalent element for one of power stages, and through utilizing higher inductance, compared to other regular phases, to reduce RMS current.
1 . A multiphase power converter comprising:
a power management integrated circuit disposed within a single package;
a source-only voltage regulator integrated within the single package and configured to directly source a load current through a first inductor to a common output node during a light-load condition, wherein the first inductor is connected between a terminal of the single package and a current source, and wherein the current source is connected between the common output node and ground; and
a plurality of power stages located external to the single package and configured to supply additional load current during a non-light load condition, wherein each of the plurality of power stages comprises:
a current sense circuit configured to generate a feedback signal based on an output of the power management integrated circuit and only upon receiving an enable signal; and
a stage selection circuit configured to generate the enable signal to each of the plurality of power stages, and wherein in the light load condition, the enable signal is not sent to the current sense circuit of one of the plurality of power stages.
2 . The multiphase power converter of claim 1 , wherein:
the power management integrated circuit is configured to activate the plurality of power stages during non-light load conditions.
3 . The multiphase power converter of claim 2 , wherein:
the power management integrated circuit is further configured to deactivate the source-only voltage regulator after activating the plurality of power stages.
4 . The multiphase power converter of claim 1 , wherein:
the source-only voltage regulator is fabricated on a first semiconductor die;
the power management integrated circuit comprises a main voltage regulator controller that is fabricated on a second semiconductor die; and
the first semiconductor die and the second semiconductor die are co-packaged within the single package.
5 . The multiphase power converter of claim 1 , wherein:
the source-only voltage regulator is fabricated on a semiconductor die, and
the power management integrated circuit comprises a main voltage regulator controller that is fabricated on the same semiconductor die within the single package.
6 . The multiphase power converter of claim 1 , wherein:
the source-only voltage regulator has a lower quiescent current than each of the plurality of power stages.
7 . The multiphase power converter of claim 1 , wherein:
the first inductor has an inductance value greater than an inductance value of a second inductor associated with each of the plurality of power stages located external to the single package.
8 . The multiphase power converter of claim 7 , wherein:
the inductance value of the first inductor is selected to reduce a root mean square current value at the common output node, thereby improving light-load efficiency.
9 . The multiphase power converter of claim 1 , wherein:
the source-only voltage regulator comprises an amplifier.
10 . The multiphase power converter of claim 9 , wherein:
a first input terminal of the amplifier is configured to receive a reference signal; and
a second input terminal of the amplifier is connected to the terminal of the single package.
11 . The multiphase power converter of claim 10 , wherein:
the power management integrated circuit is configured to provide the reference signal to ensure a proper sequence and power allocation for the source-only voltage regulator and the plurality of power stages.
12 . The multiphase power converter of claim 1 , wherein:
the source-only voltage regulator is a self-regulated voltage regulator with a built-in output current limit.
13 . The multiphase power converter of claim 12 , wherein:
a regulated voltage provided by the source-only voltage regulator is lower than a regulated voltage provided by the plurality of power stages.