The L99LD21 is a flexible LED driver, which is specifically designed for the control of two independent high brightness LED strings for automotive front lighting applications. It consists of a high efficiency monolithic boost controller and a dual buck converter.
The boost controller integrates a high current gate driver for an external n-channel mosfet. It delivers a constant output voltage, up to 60 V, which supplies the inputs of the two integrated or external buck converters.
The boost controller of two devices can be stacked, in order to operate in dual phase for high power applications, with an interleaving pattern for an improved input current ripple.
The buck converters integrate n-channel mosfet which is driven by a bootstrap circuit.
- AEC-Q100 qualified
- ST SPI communication v4.1
- 5.5 to 24V Operating battery voltage range
- Load dump protected
- QFN40L (wettable flanks) with exposed pad
- Timeout watchdog and limp home function
- Low standby current
- Boost Section
- Fixed frequency architecture, programmable by SPI
- Peak current mode control
- Dual phase operation supported
- Input current limitation
- Soft start
- Overvoltage protection (OVP)
- Short feedback failure protection
- Constant voltage control
- Buck section
- Integrated switching mosfets
- Lossless current sensing without need of external components
- Very accurate LED current setting programming inductor's peak current and peak-to-peak current ripple
- Adjustable peak current by SPI
- Adjustable current ripple by SPI
- Integrated PWM generation unit with 10-bit resolution and phase shift
- Peak current control
- Constant VLED x TOFF architecture
- Protection and diagnostic
- Battery under voltage
- Temperature warning (2 thresholds)
- Overtemperature shutdown
- LED voltage digital feedback through SPI
- Buck outputs short circuit and open load protection
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RoHS Compliance Grade
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