Abstract:
In a device (1) for driving LEDs (7) with variable light intensity, a supply stage (9) has a first operating mode, in which a controlled supply current (I out ) is generated, and a second operating mode, in which a controlled supply voltage (V out ) is generated. A LED (7) is connected to the supply stage (9), receives the controlled supply current or voltage, and has a turning-on threshold voltage higher than the controlled supply voltage (V out ). A current sensor (11) generates a current-feedback signal (V1 fb ) that is correlated to the current flowing in the LED (7) and is supplied to the supply stage (9) in the first operating mode. An intensity-control stage (13, 14) generates a mode-control signal (V2 fb ) that is sent to the supply stage (9) and controls sequential switching between the first and the second operating modes of the supply stage (9).
Abstract:
A capacitor for sensing the substrate voltage is efficiently and economically realized simply by isolating a portion or segment of the metal layer that normally covers the heavily doped perimetral region of electric field equalization and, in correspondence of such a metal segment isolated by the remaining portion, by not removing preventively the isolation dielectric layer of silicon oxide from the surface of the semiconductor substrate, as it is normally done on the remaining portion of the perimetral edge region before depositing the metal. The unremoved layer of isolated silicon oxide becomes the dielectric layer of the so constituted capacitor, a plate of which is the heavily doped perimetral region that is electrically connected to the substrate (drain or collector region) while the other plate is constituted by the segment of metal, isolated from the remaining metal layer defined directly over the heavily doped perimetral region.
Abstract:
An integrated circuit structure of the type formed on a semiconductor substrate (5) with conductivity of a first type (N), comprising a first circuit portion (2) incorporated into a first well (6) and including at least one power transistor, and a second control circuit portion (3) incorporated into a second well (7), and comprising an intermediate region (4) located between said first and second circuit portions, the first well (6), second well (7) and intermediate region (4) having conductivity of a second type (P). The integrated circuit structure according to the invention comprises a circuit means of biasing the intermediate region (4) at a value of potential which is tied to the value of potential of the first well (6), thereby cutting off a flow of parasitic current from the wells (6,7) to the semiconductor substrate (5).
Abstract:
A capacitor for sensing the substrate voltage is efficiently and economically realized simply by isolating a portion or segment of the metal layer that normally covers the heavily doped perimetral region of electric field equalization and, in correspondence of such a metal segment isolated by the remaining portion, by not removing preventively the isolation dielectric layer of silicon oxide from the surface of the semiconductor substrate, as it is normally done on the remaining portion of the perimetral edge region before depositing the metal. The unremoved layer of isolated silicon oxide (12) becomes the dielectric layer of the so constituted capacitor, a plate of which is the heavily doped perimetral region (4) that is electrically connected to the substrate (drain or collector region) while the other plate is constituted by the segment of metal (4'), isolated from the remaining metal layer defined directly over the heavily doped perimetral region (4).
Abstract:
A device for recognizing the power supply of discharge lamps comprises an output block for the power supplying of the lamp and a power-factor correction block 20 for correcting the power factor on the basis of a given conduction time. A control circuit, such as a microcontroller, which is sensitive to the supply voltage of the lamp, is able to detect the striking voltage of the lamp and to obtain a first recognition of the power supply of the lamp as a function of the striking voltage, likewise estimating the conduction time for the correction of the power factor as a function of the power supply corresponding to the aforesaid first recognition. The control circuit is configured for measuring the conduction time for the correction of the power factor effectively applied to the lamp and comparing the estimated conduction time for the correction of the power factor with the measured one. Consequently: - i) if the estimated conduction time and the measured conduction time are consistent with one another, the control circuit recognizes the power supply as the one corresponding to the first recognition; and - ii) if the estimated conduction time and the measured conduction time are not consistent with one another, the control circuit recognizes the power supply as the one corresponding to the conduction time measured.
Abstract:
The voltage converter circuit (20) with a self-oscillating half-bridge configuration has a first and a second input terminal (21a, 21b), and a first and a second output terminal (22a, 22b), and includes: a first power switch (60) coupled between the first input terminal (21a) and the first output terminal (22a), a second power switch (80) coupled between the first output terminal (22a) and the second input terminal (21b), a first voltage sensor (70) having a first and a second sensing terminals coupled between the first input terminal (21a) and a control terminal (61) of the first power switch (60), and a second voltage sensor (90) having a first and a second sensing terminals coupled between the first output terminal (22a) and a control terminal (81) of the second power switch (80). Each voltage sensor (70, 90) detects a voltage variation supplied on its respective first sensing terminal and generates on the respective second sensing terminal an activation potential for the respective power switch (60, 80).
Abstract:
An electronic differential switch (20) of the type connected to at least one phase cable (L1) and to one neutral cable (L2) of an electric network and comprising at least one toroid (2) associated with a first winding (W1) in turn associated with a second winding (W2) is described, the second winding (W2) being associated with a driving relay (3) of a main switch (T), in turn connected to the phase and neutral cables (L1, L2). The first and second windings (W1, W2) are connected to each other through the series of a measuring and driving integrated circuit (8) and of a bridge of diodes (7), the measuring and driving integrated circuit (8) being apt to measure a differential current flowing in the first winding (W1) and to generate a driving signal. Advantageously according to the invention, the electronic differential switch comprises at least one driven switch (21) connected to the integrated circuit (8) and driven thereby by means of the driving signal and connected to the relay (3) by means of the bridge of diodes (7), the driven switch (21) exciting, respectively, releasing the relay (3), which in turn closes, respectively, opens the main switch (T). A method is also described for controlling an alarming condition in an electric network comprising at least one phase cable (L1) and one neutral cable (L2) associated with a main switch (T) and connected to an electronic differential switch (20).