Abstract: A piezoelectric transformer converts a first voltage, supplied from a voltage source, into a second, different, stabilized voltage by a DC/AC converter followed by a rectifier connected in cascade to a filter. The DC/AC converter block includes a driver block followed by the piezoelectric transformer, such that the driver block feeds the piezoelectric transformer with a pulse train (21) the frequency of which coincides with the switching frequency (F1) of switching elements included in the driver block. The switching frequency (F1) is less than a resonant frequency (FR) of the piezoelectric transformer; for example, the switching frequency is a sub-harmonic of the resonant frequency (FR).

Abstract: The switched power converter comprises a first rectifier module (11-1) connected to a first capacitor (11-2) that, in turn, is connected to an excitation module (11-3) that applies a voltage to some input terminals (PT-1, PT-2) of a piezoelectric transformer (PT). A controller device (11-3-3) governs the excitation module (11-3) in order that the piezoelectric transformer (PT) works at constant frequency and regulates the power delivered to the output of the converter by enabling/disabling the voltage applied to the terminals (PT-1, PT-2). When the piezoelectric transformer (PT) is not transferring energy between its input terminals (PT-1, PT-2) and its output terminals (PT-3, PT-4), the converter output voltage is supplied by a second capacitor included in a second filter (11-6).

Abstract: Universal switched power converter having a transformer that comprises a first winding (11-3) divided into two parts and having an intermediate tap (11-3-1), and a second winding (11-9) connected in cascade with rectifier means (12) and filter means (13), so that a first current flows through the part of said first winding (11-3) comprised between the end of the primary winding (11-3) connected to a first input terminal (11-1) and the intermediate tap (11-3-1) and through a second switching element (11-6) connected to the intermediate tap (11-3-1) and to a second input terminal (11-2), when the input voltage applied across the input terminals (11-1, 11-2) is close to a first predetermined voltage value and the second switching element (11-6) is in a conducting state.

Abstract: The switched power converter comprises a first rectifier module (11-1) connected to a first capacitor (11-2) that, in turn, is connected to an excitation module (11-3) that applies a voltage to some input terminals (PT-1, PT-2) of a piezoelectric transformer (PT).

Abstract: Resonant switched power converter in which the end of a resonant period coincides with the start of a conducting period of a first switching element, undesirable dead times being avoided during the operation of a self-excited synchronous rectifier. To achieve this, a first capacitor is added which has the characteristic that its capacitance is a function of the duty cycle of the first switching element. The variation in the value of the capacitance of the first capacitor is implemented by adding in parallel thereto a serial combination of a second capacitor and a second switching element. The value of the capacitance varies between a first value and a second value.

Abstract: Universal switched power converter having a transformer that comprises a first winding (11-3) divided into two parts and having an intermediate tap (11-3-1), and a second winding (11-9) connected in cascade with rectifier means (12) and filter means (13), so that a first current flows through the part of said first winding (11-3) comprised between the end of the primary winding (11-3) connected to a first input terminal (11-1) and the intermediate tap (11-3-1) and through a second switching element (11-6) connected to the intermediate tap (11-3-1) and to a second input terminal (11-2), when the input voltage applied across the input terminals (11-1, 11-2) is close to a first predetermined voltage value and the second switching element (11-6) is in a conducting state.

Abstract: Resonant switched power converter in which the end of a resonant period coincides with the start of a conducting period of a first switching element, undesirable dead times being avoided during the operation of a self-excited synchronous rectifier.