STMicroelectronics ALED1262ZT
ALED1262ZT - Automotive-grade 12-channel LED driver with open detection, local dimming, busdriven and standalone operations
The ALED1262ZT is a monolithic 12 output LED driver designed for automotive exterior and interior lighting applications. The ALED1262ZT guarantees 19 V output driving capability allowing users to connect several LEDs in series. In the output 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 ALED1262ZT, LED open error detection is available. The brightness can be adjusted separately for each channel through a 7-bit 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 current. To further increase EMI performance, this device implements an internal clock dithering to have a spread spectrum noise reduction.
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.
Features
- Designed for automotive applications
- 12 constant current output channels
- 19 V current generator rated voltage
- Output current: from 6 mA to 60 mA
- 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
STEVAL-LLL002V1 - Evaluation kit for automotive rear lights with pattern animations based on ALED1262ZT and STM8AF6266
The STEVAL-LLL002V1 evaluation kit consists of the STEVAL-LLL002M1 main board and the STEVAL-LLL002D1 USB-UART bridge. It has been designed to test and evaluate ALED1262ZT performance.
The STEVAL-LLL002M1 is a LED array driver system evaluation board with local dimming and diagnostics for automotive applications. It is based on the ALED1262ZT 12-channel LED driver controlled through the STM8AF6266 microcontroller I²C interface.
A 48 red LED matrix is driven by four ALED1262ZT LED drivers.
The on-board A7986A DC-DC converter, accepting standard adapter input voltages with reverse polarity protection, provides the voltages and power for the board operation.
The STEVAL-LLL002V1 evaluation kit jumpers simulate LED open circuit faults and the 4-pin SWIM connector is used to debug and develop the STM8AF6266 microcontroller firmware.
The evaluation kit can operate in bus driven mode (BDM), standalone mode (SAM) and GUI mode.
In the bus driven mode, the board is controlled via on-board push buttons and potentiometers. Commands to the ALED1262ZT driver are sent by STM8A microcontroller over I²C bus.
In the standalone mode, the STEVAL-LLL002V1 evaluation kit is not controlled by the MCU and you can select two possible output configurations using OTP ½ SPDT switch (SW2).
In the GUI mode, the board is connected to a PC via USB-UART bridge and you can observe and control various features of the driver through the graphical user interface.
Features
- Various pre-configured and programmable patterns on the 12 x 4 red LED matrix
- 7 bit PWM local dimming control with non-linear steps to adjust brightness to human eye perception
- Speed control
- Push buttons to switch modes
- Safety standalone mode function and OTP pre-programmed mode for custom configuration
- Fast I²C interface with selectable extended Hamming encoding
- Open error simulation and real-time detection
- 12 to 24 V DC power supply with reverse polarity protection
- GUI for advanced driver configuration
- USB-UART bridge (STEVAL-LLL002D1) for PC connection
- RoHS and WEEE compliant
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