DC/DC converter efficiency improvement for low current levels

A power converter configured to convert electrical power at an input voltage into electrical power at an output voltage, wherein the power converter comprises a

• pre-determined number N of inverter stages, with N>1, including
• a first inverter stage comprising a first high side switch and a first low side switch which are arranged in series between the input voltage and a reference voltage;
• and
• a second inverter stage comprising a second high side switch and a second low side switch which are arranged in series between the input voltage and the reference voltage;
• wherein a midpoint between the first high side switch and the first low side switch is coupled with a midpoint between the second high side switch and the second low side switch;
• and wherein the electrical power at the output voltage is drawn from the midpoint;
• and
• wherein the power converter further comprises a controller which is configured to
• determine an indication of a requested level of the electrical power at the output voltage;
• activate or deactivate the second inverter stage based on the indication of the requested level of the electrical power at the output voltage;
• determine a default number n of active inverter stages based on the indication of the requested level of the electrical power at the output voltage, with 0<n<N;
• operate the power converter with the default number n of active inverter stages;
• wherein the default number n of active inverter stages comprises the first inverter stage;
• determine a peak of the requested level of the electrical power at the output voltage;
• and
• operate the power converter with more than the default number n of active inverter stages, subject to determining a peak of the requested level of the electrical power at the output voltage.

A method for operating a power converter which is configured to convert electrical power at an input voltage into electrical power at an output voltage, wherein the power converter comprises a first inverter stage comprising a first high side switch and a first low side switch which are arranged in series between the input voltage and a reference voltage;

• wherein the power converter further comprises a second inverter stage comprising a second high side switch and a second low side switch which are arranged in series between the input voltage and the reference voltage;
• wherein a midpoint between the first high side switch and the first low side switch is coupled with a midpoint between the second high side switch and the second low side switch;
• and wherein the electrical power at the output voltage is drawn from the midpoint;
• wherein the power converter comprises a pre-determined number N of inverter stages, with N>1;
• wherein the method comprises
• determining an indication of a requested level of the electrical power at the output voltage;
• activating or deactivating the second inverter stage based on the indication of the requested level of the electrical power at the output voltage;
• determining a default number n of active inverter stages based on the indication of the requested level of the electrical power at the output voltage, with 0<n<N;
• operating the power converter with the default number n of active inverter stages;
• wherein the default number n of active inverter stages comprises the inverter stage;
• determining a peak of the requested level of the electrical power at the output voltage;
• and
• operating the power converter with more than the default number n of active inverter stages, subject to determining a peak of the requested level of the electrical power at the output voltage.

A method of providing a controller for controlling a power converter which converts electrical power at an input voltage into electrical power at an output voltage, wherein the power converter comprises a first inverter stage comprising a first high side switch and a first low side switch which are arranged in series between the input voltage and a reference voltage;

• wherein the power converter further comprises a second inverter stage comprising a second high side switch and a second low side switch which are arranged in series between the input voltage and the reference voltage;
• wherein a midpoint between the first high side switch and the first low side switch is coupled with a midpoint between the second high side switch and the second low side switch;
• and wherein the electrical power at the output voltage is drawn from the midpoint;
• wherein the power converter comprises a pre-determined number N of inverter stages, with N>1;
• comprising the steps of:
• determining an indication of a requested level of the electrical power at the output voltage, and
• activating or deactivating the second inverter stage based on the indication of the requested level of the electrical power at the output voltage;
• determining a default number n of active integer stages based on the indication of the requested level of the electrical power at the output voltage, with 0<n<N;
• operating the power converter with the default number n of active inverter stages;
• wherein the default number n of active inverter stages comprises the first inverter stage;
• determining a peak of the requested level of the electrical power at the output voltage;
• and
• operating the power converter with more than the default number n of active inverter stages, subject to determining a peak of the requested level of the electrical power at the output voltage.