A circuit portion is provided which includes an energy harvesting device producing a DC output; a DC-DC converter having an input connected to the DC output of the energy harvesting device; an output for connection to a load; and a monitoring module including a non-ohmic semiconductor element. The monitoring module is arranged to derive information relating to an output current flowing from the DC-DC converter by measuring a current through the non-ohmic semiconductor element. The monitoring module is arranged to adjust one or more parameters of the DC-DC converter based on the information relating to said output current flowing from the DC-DC converter.

A circuit portion is provided which includes an energy harvesting device producing a DC output; a DC-DC converter having an input connected to the DC output of the energy harvesting device; an output for connection to a load; and a monitoring module including a non-ohmic semiconductor element. The monitoring module is arranged to derive information relating to an output current flowing from the DC-DC converter by measuring a current through the non-ohmic semiconductor element. The monitoring module is arranged to adjust one or more parameters of the DC-DC converter based on the information relating to said output current flowing from the DC-DC converter.

A power supply system comprises: a switched-capacitor converter, a controller, and a monitor. Via generation of control signals, the controller controls settings of switches in the switched-capacitor converter to convert a received input voltage to an output voltage that powers a load. The monitor in the power supply system at least occasionally determines an impedance associated with the switched-capacitor converter. A magnitude of the determined impedance provides an indication whether the switched-capacitor converter is operating efficiently. To ensure efficient operation of the switched-capacitor converter, based on input form the monitor, the controller adjusts the control signals controlling the switches in the switched-capacitor converter as a function of the determined impedance.

A power supply system comprises: a switched-capacitor converter, a controller, and a monitor. Via generation of control signals, the controller controls settings of switches in the switched-capacitor converter to convert a received input voltage to an output voltage that powers a load. The monitor in the power supply system at least occasionally determines an impedance associated with the switched-capacitor converter. A magnitude of the determined impedance provides an indication whether the switched-capacitor converter is operating efficiently. To ensure efficient operation of the switched-capacitor converter, based on input form the monitor, the controller adjusts the control signals controlling the switches in the switched-capacitor converter as a function of the determined impedance.

Described are circuits and techniques to increase the efficiency of radio-frequency (rf) amplifiers including rf power amplifiers (PAs) through “supply modulation” (also referred to as “drain modulation” or “collector modulation”), in which supply voltages provided to rf amplifiers is adjusted dynamically (“modulated”) over time depending upon the rf signal being synthesized. For the largest efficiency improvements, a supply voltage can be adjusted among discrete voltage levels or continuously on a short time scale. The supply voltages (or voltage levels) provided to an rf amplifier may also be adapted to accommodate longer-term changes in desired rf envelope such as associated with adapting transmitter output strength to minimize errors in data transfer, for rf “traffic” variations.

This application provides a solid-state transformer and a bus voltage equalization method for a solid-state transformer. The solid-state transformer may include a plurality of cascaded modules and a bus voltage equalization module. Input terminals of all the cascaded modules are connected in series, and output terminals of all the cascaded modules are connected in parallel, and are used as a parallel output terminal of the solid-state transformer. The bus voltage equalization module is connected in parallel to the parallel output terminal of the solid-state transformer. Each cascaded module may include a bus capacitor (for example, all capacitors connected in series to each other on a direct current bus.

This application provides a solid-state transformer and a bus voltage equalization method for a solid-state transformer. The solid-state transformer may include a plurality of cascaded modules and a bus voltage equalization module. Input terminals of all the cascaded modules are connected in series, and output terminals of all the cascaded modules are connected in parallel, and are used as a parallel output terminal of the solid-state transformer. The bus voltage equalization module is connected in parallel to the parallel output terminal of the solid-state transformer. Each cascaded module may include a bus capacitor (for example, all capacitors connected in series to each other on a direct current bus.

A conversion circuit includes a buck-boost unit and a switched capacitor unit. The buck-boost unit may perform buck conversion or boost conversion on a received first input voltage, use a first input voltage obtained after the buck conversion or boost conversion as a forward voltage, and provide the forward voltage for the switched capacitor unit. The switched capacitor unit may perform boost conversion on the forward voltage, and output a forward voltage obtained after the boost conversion as a first output voltage. The conversion circuit may support continuous adjustment of a transformation ratio, and a maximum transformation ratio of the conversion circuit is not limited by a transformation ratio of the switched capacitor unit. The first output voltage of the conversion circuit may be any voltage not less than the first input voltage.

A system includes a DC-DC converter. The DC-DC converter includes a first stage configured to reduce DC input voltage to the DC-DC converter an intermediate voltage, and a second stage configured to reduce the intermediate voltage from the first stage to a DC output voltage for output from the DC-DC converter. A controller is operatively connected to control the DC-DC converter for converting the DC input voltage to the DC output voltage.

A system includes a DC-DC converter. The DC-DC converter includes a first stage configured to reduce DC input voltage to the DC-DC converter an intermediate voltage, and a second stage configured to reduce the intermediate voltage from the first stage to a DC output voltage for output from the DC-DC converter. A controller is operatively connected to control the DC-DC converter for converting the DC input voltage to the DC output voltage.