摘要:
A power converter is provided, which may include_a transformer having primary and secondary windings; a primary side switching bridge arrangement including at least two switches switcheable at a switching frequency to drive the primary winding of said transformer, said primary side switching bridge arrangement including at least one decoupling capacitor; and a secondary side rectifying and filtering stage coupled to the secondary winding of said transformer, wherein said secondary side rectifying and filtering stage includes a current doubler with at least one inductor, wherein said at least one decoupling capacitor and said at least one inductor in said current doubler comprise a resonant tank circuit having a resonant frequency range encompassing said switching frequency, whereby said converter exhibits a gain defined by the position of said switching frequency within said resonant frequency range.
摘要:
A power converter is provided, which may include_a transformer having primary and secondary windings; a primary side switching bridge arrangement including at least two switches switcheable at a switching frequency to drive the primary winding of said transformer, said primary side switching bridge arrangement including at least one decoupling capacitor; and a secondary side rectifying and filtering stage coupled to the secondary winding of said transformer, wherein said secondary side rectifying and filtering stage includes a current doubler with at least one inductor, wherein said at least one decoupling capacitor and said at least one inductor in said current doubler comprise a resonant tank circuit having a resonant frequency range encompassing said switching frequency, whereby said converter exhibits a gain defined by the position of said switching frequency within said resonant frequency range.
摘要:
An arrangement for supplying a constant current to at least one LED includes a current source (2; 2a, 2b) with an output capacitor (3) connected across the terminals of the current source. An output inductor (4) is associated with the output capacitor (3) whereby the current supplied flows through the inductor (4). A smoothing resistor (5) is preferably connected in parallel to the output inductor (4).
摘要:
A method of protecting from over-temperature a device associated with an electronic converter including a feedback path for regulating the output signal of said electronic converter may include providing a thermal sensitive component sensitive to the temperature of said device, and including said thermal sensitive component in said feedback path of said electronic converter, whereby said output signal of said electronic converter is reduced as a function of the temperature of said device as sensed by said thermal sensitive component.
摘要:
A drive arrangement for light sources may include: a connection line to feed a light source, a switch element coupled to said line to apply on/off signals to said line, and a controller to control operation of said switch, said controller being sensitive to at least one of a dimming signal representative of a desired dimming level for said light source and an information-carrying digital signal, wherein said controller is configured to control operation of said switch to: a) PWM modulate an on/off signal applied to said line as a function of said dimming signal, whereby the average current conveyed towards said light source and determined by said PWM modulated on/off signal controls the brightness of said light source, b) transmit said information-carrying digital signal as an on/off information signal applied to said line, whereby the information carried by said information-carrying digital signal is transmitted over said line.
摘要:
In various embodiments, a method for powering light sources from a input power supply through a converter circuit is provided including a primary side and a secondary side separated by a galvanic barrier, wherein the primary side includes a power factor control block with an output capacitor. The method may include providing save circuitry on said secondary side for saving operational data of the converter upon failure of said input power supply; and powering said save circuitry during saving said operational data with energy derived from said output capacitor of said power factor control block.
摘要:
A driver arrangement for LEDs may include a PWM controller to deliver a feed voltage between an output line and a ground output line, said controller having a pin, a current regulator to regulate the feed current, a switch to connect said pin to a scaled-down version of the voltage on the first output line, and a control line to receive a signal to produce dimming, said control line coupled to said regulator and said switch to couple said regulator to a reference voltage and control switching, whereby: in one of the levels of a PWM control signal, said regulator interrupts said feed current, the voltage on said ground output line is floating, and in the other levels, said regulator is coupled to said reference voltage, said switch disconnects said pin from said voltage on the output line and the voltage on said ground output line is regulated.
摘要:
A converter for feeding a load via an inductor with a current having a controlled intensity between a maximum level and a minimum level may include: a switch switchable on and off to permit or prevent, respectively, feeding of current towards said inductor; first and second current sensors sensitive to the current flowing through said switch when said switch is on or off, respectively; comparator circuitry to identify if the current intensity detected by said first current sensor and said second current sensor reaches said maximum level and said minimum level, respectively, by generating respective logical signals; and drive circuitry for said switch sensitive to said logical signals and configured to turn off said switch when the current intensity detected by said first sensor reaches said maximum level and turning on said switch when the current intensity detected by said second current sensor reaches said minimum level.
摘要:
A converter circuit to produce a dc output signal from a stabilized input voltage may include a flyback inductor and a drive arrangement to drive said flyback inductor. A control unit is provided sensitive to the demagnetisation of said flyback inductor, said control unit configured to act on a first, a second and a third switch to effect in a cyclical manner the sequence including: a) producing a ramp-like increase of a magnetising current in said flyback inductor following activation of said first switch and said second switch; b) de-activating said first and second switch when the magnetising current in said flyback inductor reaches a predetermined peak value, c) activating said third switch thus producing energy transfer in said flyback inductor, and d) activating said first switch and de-activating said third switch when the voltage on said first electronic switch has reached zero.
摘要:
Dimming a light source such as a LED over a dimming range (0%-100%) involves adjusting at least one of the intensity (I) and the duty-cycle (DR) of a current flowing through the light source. The dimming range includes at least one portion (L%-H%; 0%-H%) where the light source is fed with a current whose intensity (I) is switched with a given duty cycle (DR) between a non-zero on value and zero, the non-zero on value being a fraction of the rated value (Irated), whereby joint CC and PWM dimming is achieved.