Abstract: In some embodiments, a power supply, for example, for battery chargers of mobile telephones, includes: a control circuit having a driving terminal coupled to a control terminal of a power transistor, where the power transistor drives a primary winding of a transformer of the power supply; a current sense input for detecting a first current flowing through the power transistor; and a switched signal generator coupled to the driving terminal, the switched signal having a period that is the sum of an active time, a dead time, and a demagnetization time of the transformer. The control circuit also includes a control network coupled to the current sense input and to the switched signal generator; a regulating network having a detection unit configured to detect the first current reaching a lower limit; and a variation unit configured to increment the dead time when the active time reaches the lower limit.

Abstract: An automated soil sampler is removably mounted on an agricultural tractor and collects soil samples in a farm field while the tractor is driven through the field. At a periodic interval, the soil sampler momentarily lowers a soil collection knife into the soil to collect a soil sample, raises the collection knife out of the soil, and transfers the collected soil sample into a bar-coded storage container. The GPS location of the soil sample is associated with the storage container's bar-code in a data file. The interval between successive periodic soil samples corresponds to a determined forward displacement of the tractor. Storage containers that have received soil samples are moved to a storage area until all of the soil samples for a given field have been collected.

Abstract: An automatic soil sampler for taking samples of topsoil has a soil breakdown assembly that cuts a shallow furrow in the soil and moves debris to the side. Soil is collected with a sampling knife having a series of empty chambers adapted to receive samples of topsoil. A rotating discus is disposed opposite the soil sampling empty chambers for urging soil into the soil sampling empty chambers. A cup carrousel carries empty identified cups for receiving soil samples. A delivery assembly places one of the empty identified cup in a cup receiving station. A filling assembly connects the knife chambers carrying collected soil samples with the cup receiving station. The cups are filled with soil samples in a collecting station. Each filled cup has its identifier sent to memory along with the location at which the sample was taken.

Abstract: An automated soil sampler is removably mounted on an agricultural tractor and collects soil samples in a farm field while the tractor is driven through the field. At a periodic interval, the soil sampler momentarily lowers a soil collection knife into the soil to collect a soil sample, raises the collection knife out of the soil, and transfers the collected soil sample into a bar-coded storage container. The GPS location of the soil sample is associated with the storage container's bar-code in a data file. The interval between successive periodic soil samples corresponds to a determined forward displacement of the tractor. Storage containers that have received soil samples are moved to a storage area until all of the soil samples for a given field have been collected.

Abstract: A receiver of a signal communication apparatus; the apparatus including a transmitter adapted to transmit coded signals, the receiver for receiving the signal and a wireless interface interposed between the transmitter and the receiver and having a transmitting antenna and a receiving antenna. The receiver includes a decoder configured to decode the received signal and circuitry coupled to the receiving antenna and capable of triggering the decoder if the value of the received signal is outside a logical hysteresis having a first logic threshold having a value smaller than the value of the direct current component of the received signal and a second logic threshold having a value greater than the value of the direct current component of the received signal.

Abstract: A receiver of a signal communication apparatus; the apparatus having a transmitter for transmitting the signals, the receiver for receiving the signals and a galvanically isolated wireless interface interposed between the transmitter and the receiver and having a transmitting antenna and a receiving antenna. The receiver including a disturbance rejection circuit coupled to the receiving antenna and capable of compensating for the parasite currents flowing between the transmitting antenna and the receiving antenna at the potential variations between the input and output of the galvanic isolation interface.

Abstract: An embodiment of a voltage converter, provided with: a voltage transformer having a primary winding receiving an input voltage, a secondary winding supplying an output voltage, and an auxiliary winding supplying a feedback voltage correlated to the output voltage; a main switch, coupled to the primary winding; a control circuit, which controls switching of the main switch and has a sampling stage for sampling and holding the feedback voltage and supplying a sampled signal; and a voltage limiting circuit, provided with a clamp capacitor, designed to be coupled across the primary winding. A sampling control stage is coupled to the sampling stage, and is designed, during a given operating condition of the voltage converter, to enable updating of the sampled signal on the basis of a state of charge of the clamp capacitor.

Abstract: An embodiment of a voltage converter, designed to convert an input voltage into a regulated output voltage, having: a voltage transformer having a primary winding receiving the input voltage, a secondary winding supplying the output voltage (Vout), and an auxiliary winding supplying a feedback signal correlated to the output voltage; a control switch, connected to the primary winding; and a control circuit, connected to a control terminal of the control switch for controlling switching thereof as a function of the feedback signal. The control circuit is provided with a sampling stage that samples the feedback signal and supplies a sampled signal. An averager stage is connected to the output of the sampling stage and implements a low-pass filtering of the sampled signal so as to reduce undesirable oscillations due to sampling.

Abstract: An embodiment of a voltage converter includes: voltage-transformer means having a primary side, designed to receive an input voltage, and a secondary side, designed to supply an output voltage; control-switch means coupled to said primary side; and a control circuit, coupled to a control terminal of said control-switch means and designed to control switching thereof as a function of a first signal correlated to said output voltage; said control circuit being provided with an error-amplifier stage, designed to process a difference between said first signal and a reference signal, wherein said error-amplifier stage is configured so as to have a transconductance characteristic with a linear-operation region, having a given slope, and at least one first clamped region, which has a slope lower than said given slope and is contiguous to said linear-operation region.

Abstract: A receiver of a signal communication apparatus; the apparatus having a transmitter for transmitting the signals, the receiver for receiving the signals and a galvanically isolated wireless interface interposed between the transmitter and the receiver and having a transmitting antenna and a receiving antenna. The receiver including a disturbance rejection circuit coupled to the receiving antenna and capable of compensating for the parasite currents flowing between the transmitting antenna and the receiving antenna at the potential variations between the input and output of the galvanic isolation interface.

Abstract: A receiver of a signal communication apparatus; the apparatus including a transmitter adapted to transmit coded signals, the receiver for receiving the signal and a wireless interface interposed between the transmitter and the receiver and having a transmitting antenna and a receiving antenna. The receiver includes a decoder configured to decode the received signal and circuitry coupled to the receiving antenna and capable of triggering the decoder if the value of the received signal is outside a logical hysteresis having a first logic threshold having a value smaller than the value of the direct current component of the received signal and a second logic threshold having a value greater than the value of the direct current component of the received signal.

Abstract: An embodiment of a voltage converter, provided with: a voltage transformer having a primary winding receiving an input voltage, a secondary winding supplying an output voltage, and an auxiliary winding supplying a feedback voltage correlated to the output voltage; a main switch, connected to the primary winding; a control circuit, which controls switching of the main switch and has a sampling stage for sampling and holding the feedback voltage and supplying a sampled signal; and a voltage limiting circuit, provided with a clamp capacitor, designed to be connected across the primary winding. A sampling control stage is connected to the sampling stage, and is designed, during a given operating condition of the voltage converter, to enable updating of the sampled signal on the basis of a state of charge of the clamp capacitor.

Abstract: An embodiment of a voltage converter, designed to convert an input voltage into a regulated output voltage, having: a voltage transformer having a primary winding receiving the input voltage, a secondary winding supplying the output voltage (Vout), and an auxiliary winding supplying a feedback signal correlated to the output voltage; a control switch, connected to the primary winding; and a control circuit, connected to a control terminal of the control switch for controlling switching thereof as a function of the feedback signal. The control circuit is provided with a sampling stage that samples the feedback signal and supplies a sampled signal. An averager stage is connected to the output of the sampling stage and implements a low-pass filtering of the sampled signal so as to reduce undesirable oscillations due to sampling.

Abstract: A water dealkylation catalyst of aromatic hydrocarbons containing at least one metal of Group VIII and eventually, one metal of group VII.sub.b deposited on a gamma alumina of special properties containing at least 1000 ppm of sulfate ions having undergone a pre-treatment in aqueous medium at a pH between 1 and 10 at a temperature below 100.degree. C. The catalysts contain rhodium on pre-treated gamma alumina and the bimetallic catalysts contain 2 metals of the group VIII or one metal of the group VII and one metal of the group VII.sub.b on pre-treated gamma alumina.

Abstract: A process for the catalytic conversion of aromatic fractions additionally containing variable proportions of C.sub.5 to C.sub.11 non-aromatic hydrocarbons, to obtain substantially pure benzene and hydrogen, by water dealkylation of the aromatic hydrocarbons and simultaneous reforming of the non-aromatic hydrocarbons, characterized in that aromatic fractions having boiling points which may be varied depending on the yield of hydrogen desired, are treated by steam at temperatures from 350.degree. C. to 600.degree. C., at a pressure of 1 to 80 bars, a volume of liquid passed per unit volume of catalyst of 0.1 to 10 and a water/hydrocarbon charge flow rate ratio of 0.2 to 4, in the presence of a dealkylation catalyst selected from at least one group VIII metal, on a support selected from a sieve L, a pretreated gamma alumina, and a mixed spinel (M.sub.x M'.sub.1-x) Al.sub.2 O.sub.4, M being a non-noble group VIII metal, and M' being selected from the group consisting of magnesium, manganese, and copper.

Abstract: Catalyst for water dealkylation of oil fractions containing monoalkylated or polyalkylated aromatic hydrocarbons, said catalyst containing at least one metal of group VIII in a proportion of 0.1 to 5% by weight on a carrier, characterized in that said carrier is a zeolite L that can be exchanged with either alkaline cations or polyvalent cations of groups V.sub.b, VI.sub.b and VII.sub.b. The zeolite L can be exchanged with a solution of metals such as lithium, sodium, caesium, chromium, manganese, and rhodium. A method of using the catalyst by contacting the hydrocarbons with the catalyst at a temperature of 400.degree.-600.degree. C., a pressure of 0-80 bars, a space velocity of the hydrocarbon of from 0.1 to 10h.sup.-1, and a water to hydrocarbon mol ratio of 2-20.

Abstract: Water dealkylation catalysts of petroleum fractions containing monoalkylated or polyalkylated aromatic hydrocarbons including at least one metal of group VIII deposited in a proportion of from 0.1 to 5% by weight on a spinel, and having deposited in a proportion of from 0.1 to 5% by weight on a spinel, and having improved properties of activity, selectivity and stability, characterized in that the carrier is a mixed spinel of the formula (M.sub.x M'.sub.1-x)Al.sub.2 O.sub.4 wherein M is a bivalent base metal of group VIII such as nickel, iron and cobalt and M' is a bivalent metal belonging to groups 2a, 7b, 1b or 2b such as magnesium, manganese, copper and zinc.The mol. ratio M/M' may vary from 0.5:1 to 50:1, preferably from 1:1 to 20:1.

Abstract: In a method of catalytic conversion of a butane cut to propane, a butane cut and hydrogen are introduced respectively into a reaction zone containing a catalyst consisting of mordenite in acid form in such a manner as to ensure that the partial pressure of hydrogen is higher than 5 bar.