ROHM 12 channel Constant Current LED drivers offer advanced communication, diagnostics, and protection

Date
12/03/2014

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BD1837xEFV-M serial input controlled constant-current LED driver

ROHM Semiconductor extends it comprehensive series of automotive LED drivers with its new AEC Q100 qualified 12 channel BD1837XEFV-M family. Due to its individual calibration and PWM features it not only offers advanced LED accuracy and flexibility but also a complete design solution for automotive clusters with a multitude of options. This and the integrated diagnostic and protection characteristics enable augmented reliability and efficiency, component as well as cost savings and in consequence, simplify extensive qualification processes.

The BD1837xEFV-M is a serial input controlled constant-current LED driver in a small HT-SSOP28 package with 10V output rating. 6 bit current brightness calibration for individual LED binning is available for each output while 6 global PWM channels allow dimming from almost 0 – 100% on all outputs. It includes 12 constant current output channels with a maximum of 50mA per channel and, in order to achieve a higher output current, the channels can be combined in parallel.

The device is able to perform comprehensive diagnostic checks (open / short load / temperature / under voltage) to detect LED failure and over temperature on chip. Due to its emergency warning, it prevents total failure of the application and makes the chip setting back to “limp function” (typically 10mA) if the external resistor fails. The settings of all internal registers can be read out to verify written information at any time while the integrated SPI interface ensures sophisticated communication even during over-temperature up to 150°. Also, slew limited switching reduces conducted and radiated noise (EMI). The BD1837xEFV-M is daisy chain compatible with ROHM’s different constant current LED drivers.

Key Features
• Package: HTSSOP28
• SPI interface for communication
• 12 constant current output channels
• Max. current per channel : 50mA
• Channels can be combined for higher output current
• 6 bit Brightness calibration for LED binning (individual setting per channel)
• Diagnostics on Iref
• Limp home functionality
• Active and Passive open/short detect with own error flag
• 6 PWMs with separate inputs (can be mapped to any channel)
• PWM dimming 0.1-100% global
• PWM diagnostics
• Over Temperature Protection and thermal Feedback
• Communication during over-Temperature
• Emergency warning pin
• Read-back of all register settings
• Daisy chain possible
• AEC Q-100 qualified for automotive
• Slew limited switching reduces conducted and radiated Noise (EMI).

Key Specifications
• Input voltage range: 3.0V to 5.5V
• Output voltage range: 0.5V to 10V
• Output Current range/channel: 15mA to 50mA
• Output Current accuracy at 30mA: 3.5% (Typ.)
• Min PWM ON Time: 5uS
• Maximum circuit current: 5mA
• Maximum clock frequency: 1250KHz
• Operating temperature range: -40℃ to +105℃

ROHM Semiconductor

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