公开(公告)号：EP3923683A1

公开(公告)日：2021-12-15

申请号：EP21177957.4

申请日：2021-06-07

Applicant: STMicroelectronics S.r.l.

Inventor： SEMINARA, Maria Francesca ,  MUSUMECI, Salvatore Rosario

IPC: H05B45/325

Abstract: A LED driver system (200) adapted to be coupled to an array of LEDs (102) for driving said array of LEDs is provided. The LED driver system comprises:
- a power transistor (N1) configured to be selectively activated for generating a driving current (Iset) for the array of LEDs, the power transistor having a first conduction terminal coupled to the array of LEDs (102) and a second conduction terminal coupled to a reference resistor (Rset);
- an operational amplifier (130) having a non-inverting input for receiving a reference voltage (Vref), an inverting input coupled to the second conduction terminal of the power transistor (N1) , and an output terminal coupled to a first conduction terminal of a transmission gate (TG1), said transmission gate having a second conduction terminal coupled to a control terminal of the power transistor (N1) and a control terminal for receiving an enable signal (ENA), said first and second conduction terminals of the transmission gate (TG1) being electrically connected to each other when the enable signal is at an enabling value to cause activation of said power transistor (N1) , and being electrically insulated from each other when the enable signal is at a disabling value to cause deactivation of said power transistor (N1);
- a slew rate control unit (210) configured to control the slew rate of the driving current (Iset), the slew rate control unit being configured to selectively charge an equivalent parasitic capacitance (C) at the control terminal of the power transistor (N1) through a charging current (Ich) and to selectively discharge said equivalent capacitance (C) through a discharging current (Idsch), said charging current and said discharging current depending at least in part on a target value ( Iset(h) ) of the driving current.

公开(公告)号：EP4284120A1

公开(公告)日：2023-11-29

申请号：EP23173538.2

申请日：2023-05-16

Applicant: STMicroelectronics S.r.l.

Inventor： SEMINARA, Maria Francesca ,  MUSUMECI, Salvatore Rosario

IPC: H05B45/52 ,  H05B45/46

Abstract: 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.