A switching power supply system includes a switching converter, to convert an input voltage into an output voltage and to generate a switching signal; a feedback circuit, to generate a feedback signal; an error amplifier to generate an error signal; a triangle signal generator to generate a triangle signal; a constant on time control circuit to receive error signal and the triangle signal, and to generate a constant on time control signal to control power switch; in the system. The triangle signal has a DC bias based on either a soft start signal or a second reference signal. The system could perform soft start function and meanwhile keep matching between the error signal and the triangle signal.

A stacked switched capacitor (SSC) energy buffer circuit includes a switching network and a plurality of energy storage capacitors. The switching network need operate at only a relatively low switching frequency and can take advantage of soft charging of the energy storage capacitors to reduce loss. Thus, efficiency of the SSC energy buffer circuit can be extremely high compared with the efficiency of other energy buffer circuits. Since circuits utilizing the SSC energy buffer architecture need not utilize electrolytic capacitors, circuits utilizing the SSC energy buffer architecture overcome limitations of energy buffers utilizing electrolytic capacitors. Circuits utilizing the SSC energy buffer architecture (without electrolytic capacitors) can achieve an effective energy density characteristic comparable to energy buffers utilizing electrolytic capacitors. The SSC energy buffer architecture exhibits losses that scale with the amount of energy buffered, such that a relatively high efficiency can be achieved across a desired operating range.

A power converter can include: N switching power stage circuits, where output terminals of the N switching power stage circuits are connected in parallel, and N is a positive integer; an energy storage element coupled between an input terminal and the output terminal of the power converter, where the energy storage element is configured to periodically store energy for delivery to the output terminal of the power converter; and where after a main transistor of an M-th switching power stage circuit is turned off, a main transistor of the (M+1)-th switching power stage circuit is turned on, in order to realize zero-voltage-switching (ZVS) of the main transistor of (M+1)-th switching power stage circuit, where M is a positive integer less than N.

Disclosed herein is a AC direct LED driving apparatus. The light emitting diode (LED) driving apparatus includes: a rectifier configured to receive and rectify an alternating current (AC) voltage; an LED configured to emit light based on a rectified voltage received from the rectifier; a capacitor connected to a first terminal of the LED, and configured to drive the LED while alternating between charging and discharging sections according to a preset cycle; a first current driver connected to a second terminal of the LED and configured to control a path of current flowing in the LED and the capacitor based on different input voltage levels; a second current driver configured to control charging and discharging of the capacitor; and a first diode connected onto a current path of the capacitor and the second current driver, and configured to form a discharging path for driving the LED based on a charged voltage of the capacitor.

A dc-dc converter can include a plurality of switches, a piezoelectric resonator (PR) for power stage energy storage, and a means for controlling one or more switching sequences. The switches operate in accordance with the switching sequences to transfer energy from the input to the output via the PR while providing low-loss resonant soft-charging of the PR's capacitance. The switching sequences include: connected stages in which a first and second PR terminals are both connected to one of the input, the output, or the other PR terminal; and open stages in which at least one of the first or second PR terminal is not connected by a closed switch to one of the input, the output, or the other PR terminal.

A power converter converts a medium-voltage output from a solar module to an appropriate voltage to power a solar tracker system. The power converter includes a voltage divider having at least two legs, a first semiconductor switch subassembly coupled in parallel with a first leg of the voltage divider, and a second semiconductor switch subassembly coupled in parallel with a second leg of the voltage divider. The power converter may be a unidirectional or a bidirectional power converter. In implementations, the signals for driving the semiconductor switches of the first and second semiconductor switch subassemblies may be shifted out of phase from each other. In implementations, if the bus voltages to the semiconductor switches are not balanced, the pulse width of the driving signal of the semiconductor switch supplied with the higher bus voltage is decreased for at least one cycle.

A power conversion circuit includes an N-level PWM power converter and a switching capacitor power converter. The N-level PWM power converter includes shared switches shared with the switching capacitor power converter, and PWM switches. In an N-level PWM mode, the shared switches and the PWM switches periodically switch an inductor and a capacitor, to execute power conversion between a first power and a second power by N-level PWM switching operation. The switching capacitor power converter includes the shared switches and auxiliary switches. In a capacitive conversion mode, the shared switches and the auxiliary switches periodically switch the capacitor, to execute power conversion between the first power and the second power by capacitive power conversion operation. In the capacitive conversion mode, a portion of the plural PWM switches are always OFF such that one end of the inductor is floating.

A dielectric elastomer power generation system of the invention includes: a power generation unit including a dielectric elastomer power generation element having a dielectric elastomer layer flanked by two electrode layers; a step-down unit including capacitors; a power storage unit for input of an output power from the step-down unit; and a control unit that controls the connection between the step-down unit and the power generation unit or power storage unit. The step-down unit includes first diodes and second diodes, where the first diodes form a circuit that connects the capacitors in series when the power generation unit is connected to the step-down unit, and the second diodes form a circuit that connects the capacitors in parallel when the step-down unit is connected to the power storage unit. This configuration serves to store the generated power more efficiently in the power storage unit, e.g., a secondary battery.

An electronic device including a voltage divider adaptively changing a voltage division ratio is provided. The electronic device comprises a rechargeable battery; a connector configured to connected the electronic device with an external electronic device; a voltage divider comprising a plurality of capacitors and a plurality of switches for switching an electrical path between each of the plurality of capacitors and the rechargeable battery, wherein the voltage divider is configured to provide three or more voltage division ratios; and a processor operably coupled with the voltage divider and the connector, wherein the processor is configured to: receive an indicator indicating a first voltage of a first power from the external electronic device; select a voltage division ratio from the three or more division ratios, based at least in part on the indicator; and control the plurality of switches on the basis of the selected voltage division ratio, and wherein the voltage divider is configured to: charge a rechargeable battery with a second voltage by dividing the first voltage according to the selected voltage division ratio.

An electronic device including a voltage divider adaptively changing a voltage division ratio is provided. The electronic device comprises a rechargeable battery; a connector configured to connected the electronic device with an external electronic device; a voltage divider comprising a plurality of capacitors and a plurality of switches for switching an electrical path between each of the plurality of capacitors and the rechargeable battery, wherein the voltage divider is configured to provide three or more voltage division ratios; and a processor operably coupled with the voltage divider and the connector, wherein the processor is configured to: receive an indicator indicating a first voltage of a first power from the external electronic device; select a voltage division ratio from the three or more division ratios, based at least in part on the indicator; and control the plurality of switches on the basis of the selected voltage division ratio, and wherein the voltage divider is configured to: charge a rechargeable battery with a second voltage by dividing the first voltage according to the selected voltage division ratio.