A SiC epitaxial wafer includes a SiC substrate and a SiC epitaxial layer disposed on the SiC substrate. The SiC epitaxial layer includes a high carrier concentration layer and two low carrier concentration layers having lower carrier concentration than the high carrier concentration layer, and being in contact with a top surface and a bottom surface of the high carrier concentration layer to sandwich the high carrier concentration layer. A difference in carrier concentration between the high carrier concentration layer and the low carrier concentration layers is 5×10.sup.14/cm.sup.3 or more and 2×10.sup.16/cm.sup.3 or less.

An electronic device including a power source providing a source voltage, a capacitor, a primary regulator circuit, an always-on load that is active during a low power mode, and a recycle control circuit. The primary regulator circuit receives the source voltage and has an output that maintains a charge on the capacitor during an active mode. The primary regulator circuit does not contribute to a charge on the capacitor during the low power mode. The recycle control circuit includes a select circuit and a select control circuit. The select circuit selects, based on a control signal, between the voltage of the capacitor and at least one supply voltage including or otherwise developed using the source voltage to provide power to the always-on load during the low power mode. The select control circuit provides the control signal to control power provided to the always-on load during the low power mode.

An electronic device including a power source providing a source voltage, a capacitor, a primary regulator circuit, an always-on load that is active during a low power mode, and a recycle control circuit. The primary regulator circuit receives the source voltage and has an output that maintains a charge on the capacitor during an active mode. The primary regulator circuit does not contribute to a charge on the capacitor during the low power mode. The recycle control circuit includes a select circuit and a select control circuit. The select circuit selects, based on a control signal, between the voltage of the capacitor and at least one supply voltage including or otherwise developed using the source voltage to provide power to the always-on load during the low power mode. The select control circuit provides the control signal to control power provided to the always-on load during the low power mode.

A charging device of the present invention includes a DC-DC converter, a charging circuit that charges a secondary battery, a power supply voltage detecting circuit that detects an input voltage Ve, an output voltage setting circuit that sets an output voltage of the DC-DC converter, and a charging control section that controls the charging circuit and the output voltage setting circuit based on the input voltage Ve, and the charging control section increases the output voltage of the DC-DC converter by a predetermined voltage in a stepwise manner while monitoring the input voltage Ve, and in a case where the input voltage Ve is decreased to a first threshold voltage Vth1 or less before the output voltage of the DC-DC converter increases to a rated charging voltage, the charging control section keeps the output voltage of the DC-DC converter at a voltage that is one step lower than a voltage at a time point of the case.

A charging device of the present invention includes a DC-DC converter, a charging circuit that charges a secondary battery, a power supply voltage detecting circuit that detects an input voltage Ve, an output voltage setting circuit that sets an output voltage of the DC-DC converter, and a charging control section that controls the charging circuit and the output voltage setting circuit based on the input voltage Ve, and the charging control section increases the output voltage of the DC-DC converter by a predetermined voltage in a stepwise manner while monitoring the input voltage Ve, and in a case where the input voltage Ve is decreased to a first threshold voltage Vth1 or less before the output voltage of the DC-DC converter increases to a rated charging voltage, the charging control section keeps the output voltage of the DC-DC converter at a voltage that is one step lower than a voltage at a time point of the case.

A power supply control device includes a charge circuit, a detection circuit, and a charge control circuit. The charge circuit charges a capacitor coupled to a power supply voltage node based on a full-wave rectified voltage. The charge control circuit enables a charge mode of the charge circuit when the detection circuit detects that a power supply voltage is less than a first threshold voltage. The charge control circuit disables the charge mode when the detection circuit detects that the power supply voltage reached a second threshold voltage. The charge control circuit sets a charge capacity of the charge circuit in a second charge mode period according to a length of a first charge mode period.

A power supply control device includes a charge circuit, a detection circuit, and a charge control circuit. The charge circuit charges a capacitor coupled to a power supply voltage node based on a full-wave rectified voltage. The charge control circuit enables a charge mode of the charge circuit when the detection circuit detects that a power supply voltage is less than a first threshold voltage. The charge control circuit disables the charge mode when the detection circuit detects that the power supply voltage reached a second threshold voltage. The charge control circuit sets a charge capacity of the charge circuit in a second charge mode period according to a length of a first charge mode period.

This application provides a switched-capacitor converter circuit, a charging control system, and a control method. In the switched-capacitor converter circuit, input terminals of N levels of switched-capacitor converter units are sequentially connected in series, and output terminals of the N levels of switched-capacitor converter units are connected in parallel, to obtain a first power supply branch to supply power to a load. In addition, a first capacitor acts as a second power supply branch to supply power to the load, and the first power supply branch and the second power supply branch transmit power in parallel. In comparison with a serial power transmission manner, there are fewer devices on a power transmission path when a parallel power transmission manner is used. Therefore, this can reduce power losses on the transmission path, and improve transmission efficiency of the switched converter circuit.

This application provides a switched-capacitor converter circuit, a charging control system, and a control method. In the switched-capacitor converter circuit, input terminals of N levels of switched-capacitor converter units are sequentially connected in series, and output terminals of the N levels of switched-capacitor converter units are connected in parallel, to obtain a first power supply branch to supply power to a load. In addition, a first capacitor acts as a second power supply branch to supply power to the load, and the first power supply branch and the second power supply branch transmit power in parallel. In comparison with a serial power transmission manner, there are fewer devices on a power transmission path when a parallel power transmission manner is used. Therefore, this can reduce power losses on the transmission path, and improve transmission efficiency of the switched converter circuit.

A circuit includes a regulation circuit configured to intercept messages on a configuration channel of a universal serial bus (USB) cable between a USB source device and a USB sink device. The regulation circuit regulates a source capability message from the USB cable configuration channel based on a predetermined power capability of the USB cable.