Stmicroelectronics S.r.l.

St-Ericsson Sa

Maria Francesca Seminara

Salvatore Rosario Musumeci

Patrizia Milazzo

Marianna Sanza

A LED driver chip includes driver circuits, each being coupled to a different pin and including a fault-detection circuit. Each fault-detection circuit includes a force circuit forcing current to a force node, and a sense circuit including a current sensor coupled to the force node, and a comparator comparing a voltage at the force node to a reference voltage to generate a comparison output. Control circuitry, in a pin-to-pin short detection mode, activates the force circuit of a first of the driver circuits and activates thep sense circuit of a second of the driver circuits, in a pin-to-ground short detection mode, activates the force and the sense circuit of the same driver circuits. The comparison output of the comparator of the activated sense circuit, if is higher or if lower of the reference voltage, indicates if short between pin or to ground, respectively, is present.

LED array driver with channel to channel and channel to ground external PIN short detection

An embodiment LED driver system comprises a power transistor configured to be selectively activated for generating a driving current for an array of LEDs, the power transistor having a first conduction terminal coupled to the array of LEDs and a second conduction terminal coupled to a reference resistor; an operational amplifier having a non-inverting input for receiving a reference voltage, an inverting input coupled to the second conduction terminal of the power transistor, and an output terminal coupled to a first conduction terminal of a transmission gate having a second conduction terminal coupled to a control terminal of the power transistor and a control terminal for receiving an enable signal; and a slew rate control unit configured to control the slew rate of the driving current.

LED array driver system

A LED driver chip includes driver circuits, each being coupled to a different pin and including a fault-detection circuit. Each fault-detection circuit includes a force circuit forcing current to a force node, and a sense circuit including a current sensor coupled to the force node, and a comparator comparing a voltage at the force node to a reference voltage to generate a comparison output. Control circuitry, in a pin-to-pin short detection mode, activates the force circuit of a first of the driver circuits and activates the sense circuit of a second of the driver circuits, in a pin-to-ground short detection mode, activates the force and the sense circuit of the same driver circuits. The comparison output of the comparator of the activated sense circuit, if is higher or if lower of the reference voltage, indicates if short between pin or to ground, respectively, is present.

LED array driver with channel to channel and channel to ground external pin short detection

A multiphase buck converter () is disclosed, comprising: &#x2014;a first buck converter branch (SD, L) comprising a first core section (COR), a first power section (PWR) having a first output node (LX), a first coil () having a first end connected to the first output node (LX), the first power section (PWR) being adapted to be controlled by the first core section (COR) for providing to the coil (L) a coil current (I), the first core section (COR) and the first power section (PWR) being integrated in a chip (IC); &#x2014;a second buck converter branch (SD, L) comprising a second core section (COR), a second power section (PWR) having a second output node (LX), a second coil (L) having a first end connected to the second output node (LX), the second power section (PWR) being adapted to be controlled by the second core section (COR) for providing to the second coil (L) a second coil current (I), the second core section (COR) and the second power section (PWR) being integrated in said chip (IC); &#x2014;a feedback loop adapted to balance said coil currents (I,I). The feedback loop comprises a control block (C_B) that, in order to balance said coil currents, is adapted to compare a first average voltage at the first output node (LX) with a second average voltage at the second output node (LX) and control the first (SD, L) and second branch (SD, L) in order to make said first and second average voltages equal to each other. The control block (C_B) is integrated in said chip (IC) and has a first input directly connected to said first output node (LX) and a second input directly connected to said second output node (LX). The control block (C_B) is adapted to directly obtain said first and second average voltages from the instantaneous voltages of the first (LX) and second (LX) output nodes.

Multiphase buck converter and multiphase buck conversion method

An electronic power supply circuit for a load composed of at least two independent circuit branches connected in parallel to each other, where a first branch requires a different power supply voltage from the power supply voltage of a second branch. The circuit includes a step-up converter, a timer circuit connected to the step-up converter so that the converter generates, alternately, at least a first output voltage able to power the first circuit branch and a second output voltage able to power a second circuit branch, a regulation circuit able to regulate the overvoltages at the ends of an output capacitor of the converter during commutations between the different output voltages; and a commutation circuit able to activate the step-up converter, according to the timer signals coming from the timer circuit, when the output voltage at the ends of the output capacitor has reached the level needed to power the activated branch and regulate the current flowing thereto.

Growing community of inventors

Catania, Italy

Maria Francesca Seminara