64 results about "Class e amplifier" patented technology

A power supply including an inverter receiving a DC input signal from a DC input source (11). The inverter is implemented as a single-ended inverter. Each inverter is driven by a signal source (13A, 13B), which outputs an AC signal. The output from each inverter is input to a first stage harmonic filter. The power supply includes an output circuit that includes a rectifier (D1) arranged about a point so that if the inverter attempts to drive the point beyond a predetermined voltage, the rectifier conducts in order to return at least one of power and current to the DC input source. The output from the first harmonic filter (L1A, C1; L1B, C1) is output to a second harmonic filter (L2, C2) and is then output from the power supply.

The object of the invention is to provide a small-sized noncontact IC card reader / writer that can enhance the efficiency of an amplifier at a low cost. To achieve the object, in the invention, a loop antenna that supplies electric power and a send signal to a noncontact IC card by electromagnetic induction and acquires a receive signal from the noncontact IC card by load fluctuation, a first resonance circuit for resonating the loop antenna with a desired first frequency, a radio transmitter that supplies electric power and send data to the loop antenna via the first resonance circuit and further, a radio receiver that acquires the receive signal from the loop antenna via a second resonance circuit connected to the loop antenna via a coupling capacitor and resonated with a desired second frequency are provided, the radio transmitter and the radio receiver are respectively connected to CPU, and a low-pass filter for removing a high frequency, a class E amplifier and a modulator are connected to the radio transmitter in series.

An inductive power transfer system (10) for roadways includes at least one drive unit arrangement (50) coupled to at least one drive coil arrangement (40) disposed along a roadway (20) for generating a magnetic field extending upwardly from the roadway (20), and at least one vehicle (30) including a corresponding pickup coil arrangement (60) coupled to a power conditioning circuit arrangement (80, 200) for receiving the extending magnetic field for providing power to operate the at least one vehicle (30). The at least one drive unit arrangement (50) is operable to excite, for example at resonance, the at least one drive coil arrangement (40) at a fundamental frequency (f0) of at least 30 kHz, preferably at least 50 kHz, more preferably at least 100 kHz, and most preferably at least 140 kHz. The at least one drive coil arrangement (40) is implemented to be substantially devoid of ferromagnetic components for providing a path for the extending magnetic field. Optionally, the at least one drive unit arrangement (50) is operable to employ a balanced class-E amplifier arrangement for exciting the at least one drive coil arrangement (40) at the fundamental frequency (f0). Optionally, the at least one drive unit arrangement (50) is operable to employ one or more Silicon Carbide semiconductor devices for switching the currents provided to the corresponding at least one drive coil arrangement (40). Optionally, there is further included a passive and / or active suppression arrangement (100, 110, 120, 130, 140) for suppressing harmonic magnetic field components generated by the system (10) at multiples of the fundamental frequency (f0) when in operation.

An inductive power transfer system comprises a transmitter circuit comprising a transmitter coil and a receiver circuit comprising a receiver coil spaced from the transmitter coil. The transmitter circuit is in the form of a Class E amplifier with a first inductor and a transistor in series between the terminals of a power supply. A first transmitter capacitance is in parallel with the transistor between the first inductor and a power supply terminal, a primary tank circuit in parallel with the first transmitter capacitance, the primary tank circuit comprising the transmitter coil and a second transmitter capacitance arranged in parallel with the transmitter coil, and a third transmitter capacitance in series with the first inductor between the first transmitter capacitance and the primary tank circuit. The second transmitter capacitance is selected such that a resonant frequency of the primary tank circuit is not equal to the first frequency.