An internal voltage generation circuit of a smart card to perform fingerprint authentication and a smart card includes a first contact switch, a second contact switch, a switched capacitor converter and a bidirectional switched capacitor converter. The first contact switch selectively switches a contact voltage to a first node based on a first switching enable signal, in a contact mode. The second contact switch selectively switches the contact voltage to a second node based on a second switching enable signal, in the contact mode. The bidirectional switched capacitor converter steps down a first driving voltage of the first node to provide a second voltage to the second node in the contactless mode and either steps down the first driving voltage or boosts a second driving voltage of the second node based on a level of the contact voltage to provide a boosted voltage to the first node in the contact mode.

A resonant switching power converter includes: at least one capacitor; switches coupled to the at least one capacitor; at least one charging inductor; at least one discharging inductor; and a zero current estimation circuit. The switches switch electrical connection relationships of capacitors according to an operation signal. The zero current estimation circuit estimates a time point at which a charging resonant current is zero during a charging process and/or estimate a time point at which a discharging resonant current is zero during at least one discharging process according to voltage differences across two ends of the charging inductor and/or the discharging inductor, so as to correspondingly generate a zero current estimation signal. The zero current estimation signal is adopted to generate the operation signal.

A converter includes two switching stages coupled in series between positive and negative input terminals. A control circuit is configured for driving the switching stages based on an output voltage of the converter. A first switching stage includes two switches coupled in series between a positive input terminal and a first node. A capacitor and an inductor are coupled in series between the two switches and a positive output terminal. A third switch is coupled between a node between the capacitor and the inductor and the negative input terminal. A second capacitor is coupled between the first node and the negative input terminal. A second switching stage includes a second node coupled to the first node. Two additional electronic switches are coupled in series between the second node and the negative input terminal. A second inductor is coupled between the two additional switches and the positive output terminal.

An the LED driving circuit, for driving an the LED load, includes: a bridge rectifier for rectifying an AC input voltage into a DC voltage; a serial capacitor voltage divider coupled to the bridge rectifier, including a plurality of serial capacitors; a half-bridge switch, coupled to the serial capacitor voltage divider; and a controller coupled to the half-bridge switch, for determining whether the DC voltage is higher than a threshold value and for controlling the half-bridge switch in a full-voltage mode or a half-voltage mode. In the full-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider synchronously supply power to the LED load. In the half-voltage mode, the plurality of serial capacitors of the serial capacitor voltage divider alternatively supply power to the LED load.

A two-stage power converter includes: a resonant switched-capacitor converter (RSCC) receiving an input voltage and generating a first stage voltage; a voltage regulator receiving the first stage voltage and generating an output voltage; and a communication interface and control circuit generating a charging operation signal, at least one discharging operation signal and a switching signal. The charging operation signal and the discharging operation signal are employed to control the RSCC to perform a charging process and at least one discharging process respectively, and the switching signal is employed to control the voltage regulator, so as to synchronize a resonant frequency of the RSCC and a switching frequency of the voltage regulator. The communication interface and control circuit adjusts a delay interval after the discharging process ends, and starts the charging process at an end time point of the delay interval.

A voltage converter includes a charging circuit that includes a plurality of switches, and a first capacitor connected to a first node and that outputs an output voltage based on an input voltage, a switch controller that generates a charging switching signal based on the output voltage and a reference voltage, a charging switch that is connected between the first node and a ground node and turn on or turn off in response to a gate voltage, and a gate voltage controller configured to generate the gate voltage based on a voltage of the first node. The maximum level of the gate voltage may be lower than the maximum level of each of the charging switching signal.

A resonant switching power converter includes: capacitors; switches; at least one charging inductor; at least one discharging inductor; a controller generating a charging operation signal corresponding to charging process and discharging operation signals corresponding to discharging processes, to operate the switches to switch electrical connection relationships of the capacitors. In the charging process, the controller controls the switches via the charging operation signal, so that a series connection of the capacitors and the charging inductor is formed between the input voltage and the output voltage, which forms a charging path. In the discharging processes, the controller controls the switches via the discharging operation signals, so that a series connection of one of the capacitors and the discharging inductor is formed between the output voltage and a ground voltage level, to form plural discharging paths at different periods in a sequential order.

An apparatus is disclosed for operating a charge pump in a high-efficiency low-ripple burst mode. In an example aspect, the apparatus includes a charge pump with a flying capacitor, a switching circuit, and a burst-mode controller. The switching circuit is coupled to the flying capacitor and configured to selectively: be in a burst configuration to charge and discharge the flying capacitor based on a clock signal; or be in a pulse-skipping configuration. The burst-mode controller is coupled to the switching circuit and configured to trigger the switching circuit to transition from the pulse-skipping configuration to the burst configuration at a time that occurs between rising edges of the clock signal. The burst-mode controller is also configured to cause charging of the flying capacitor to occur for approximately half a period of the clock signal responsive to triggering the switching circuit to transition from the pulse-skipping configuration to the burst configuration.

A power converter can include: positive and negative input terminals configured to receive an input voltage; positive and negative output terminals configured to generate an output voltage; first and second power switches sequentially coupled in series between the positive input terminal and a first node; third and fourth power switches sequentially coupled in series between a second node and the negative input terminal, where there is no physical connection between the first node and the second node; a first energy storage element coupled between a common terminal of the first and second power switches and a common terminal of the third and fourth power switches; a first multi-level power conversion circuit coupled between the first node and the positive output terminal; and a second multi-level power conversion circuit coupled between the first node and the positive output terminal.

A single integrated circuit DC-to-DC conversion solution that can be used in conjunction with product designs requiring at least two different DC-to-DC conversion ratios, and in particular both divide-by-2 and divide-by-3 DC-to-DC buck conversion ratios or both multiply-by-2 and multiply-by-3 DC-to-DC boost conversion ratios. Embodiments are reconfigurable between a first Dickson converter configuration that includes at least two non-parallel capacitors (any of which may be off-chip) and associated controlled multi-phase switching to achieve a first conversion ratio, and a second Dickson converter configuration that includes a lesser equivalent number of capacitors than the first circuit configuration (which may be accomplished by parallelizing at least two non-parallel capacitors of the first configuration) and associated controlled multi-phase switching to achieve a second conversion ratio different from the first conversion ratio.