Datasheet ALED1262ZT (STMicroelectronics)

ALED1262ZT
Datasheet Automotive-grade 12-channel LED driver with open detection, local dimming, bus driven and standalone operations
Features
• Designed for automotive applications • 12 constant current output channels • 19 V current generator rated voltage • Output current: from 6 mA to 60 mA HTSSOP24 exposed pad • Current programmable by a single external resistor • 7-bit PWM local brightness control • Slow turn-on/off time, gradual output delay and dithered clock for EMI reduction • Error detection for open LEDs • Supply voltage: from 5.5 V to 38 V • Thermal shutdown and overtemperature alert • Standalone and bus-driven mode • Custom configuration by OTP with Redundancy and ECC • 400 kHz fast I²C interface with selectable extended Hamming encoding • Wired-OR error flag connection
Applications
• Automotive rear lights • Automotive interior lighting
Description
The ALED1262ZT is a monolithic 12 output LED driver designed for automotive
Maturity status link
exterior and interior lighting applications. The ALED1262ZT guarantees 19 V output driving capability allowing users to connect several LEDs in series. In the output ALED1262ZT stage, twelve regulated current sources provide from 6 mA to 60 mA constant current to drive LEDs. The current is programmed by a single external resistor. In the
Device summary
ALED1262ZT, LED open error detection is available. ALED1262ZT The brightness can be adjusted separately for each channel through a 7-bit
Order code
ALED1262ZTTR grayscale control. A slow turn-on and turn-off time improves the system low noise generation performance. Moreover the gradual output delay reduces the inrush
Package
HTSSOP24 exposed pad current. To further increase EMI performance, this device implements an internal 62 parts per tube clock dithering to have a spread spectrum noise reduction.
Packing
2500 parts per reel Thermal management is equipped with overtemperature data alert and the output thermal shutdown (170 °C). The I²C high clock frequency, up to 400 kHz, makes the device suitable for high data rate transmissions. The supply voltage range is between 5.5 V and 38 V avoiding any external pre-regulation or additional load dump protection on the power supply stage. This device can operate in bus-driven mode (BDM) using I²C interface or in standalone mode (SAM) using internal custom configuration by OTP.
DS12631
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Rev 4
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February 2019
www.st.com For further information contact your local STMicroelectronics sales office. Document Outline 1 Pin description 2 Absolute maximum ratings 3 Thermal characteristics 4 Electrical characteristics 4.1 Switching characteristics 5 Device pin functions 6 Driver dropout voltage 7 Device functional description 8 Error detection 9 Gradual output delay 10 Thermal warning and protection 11 Device local dimming function 12 Local dimming non-linear step table 13 Register descriptions 13.1 BDM_conf_1 / Enable_CH_1 register 13.2 BDM_conf_2 / Enable_CH_2 register 13.3 BDM_status register 13.4 Faulty_ch_1 register 13.5 Faulty_ch_2 register 13.6 PWM_gain_x register 13.7 LDD register (LED driver device versioning) 13.8 OTP/SAM_conf_1_2 register 13.9 OTP/SAM_conf_1 register 13.10 OTP/SAM_conf_2 register 13.11 OTP/BA_n_SAM_setting register 14 I²C bus operations 14.1 I²C main concepts 15 I²C addressing for the ALED1262ZT 16 I²C selectable Hamming (8, 4) encoding 17 Message structure 17.1 Available commands 17.2 Pattern symbols 17.3 Write operations 17.3.1 BDM configuration register write 17.3.2 FAULTY_ch1[7] bit register write (prescaler) 17.3.3 PWM_gain_x register write 17.3.4 BDM_conf and PWM_gain_x register write 17.3.5 Direct write on registers 17.4 Read operations 17.4.1 Status register 17.4.2 Faulty_ch registers 17.4.3 PWM_gain_x registers 17.4.4 BDM_conf, status, Faulty_ch, PWM_gain_x registers 17.4.5 Direct read from registers 18 OTP operations 18.1 OTP emulate 18.2 OTP burn 18.3 OTP read 19 I²C communication examples 19.1 Communication without parity detection 19.1.1 OTP burning with double zap and read back 19.1.2 All LEDs with power-ON 19.1.3 110 Hz dimming prescaler bit 19.1.4 All LEDs with PWM dimming at 50% (full configuration) 19.1.5 Device status read back 19.1.6 Device full status read back 19.1.7 LDD read back (device identifier) 19.2 Communication with parity detection 19.2.1 All LEDs with power-ON 20 LED supply voltage 21 Higher current requests (outputs in parallel) 22 PCB layout and external component guidelines 22.1 Signal integrity and EMI radiated/conducted immunity 22.2 Radiated emission reduction (EMI) 22.3 Device thermal management 22.4 PCB layout example 23 Package information 23.1 HTSSOP24 exposed pad package information Revision history