L99LD21Q6TR STMicroelectronics

L99LD21 High power LED driver for automotive applications Datasheet - production data Peak current control Constant VLED x TOFF architecture Protection and diagnostic Battery under voltage 4)1 / Temperature warning (2 thresholds) * * 36 Overtemperature shutdown LED voltage digital feedback through SPI Features Buck outputs short circuit and open load AEC-Q100 qualified protection General Applications ST SPI communication v4.1 5.5 to 24 V Operating battery voltage range Low Beam Load dump protected High beam QFN40L 6x6 (wettable flanks) with Daytime running light exposed pad Timeout watchdog and limp home function Turn indicator Low standby current Position light Boost Section Side marker Fixed frequency architecture, Fog light programmable by SPI Peak current mode control Description Dual phase operation supported The L99LD21 is a flexible LED driver, which is Input current limitation specifically designed for the control of two Soft start independent high brightness LED strings for Overvoltage protection (OVP) automotive front lighting applications. It consists Short feedback failure protection of a high efficiency monolithic boost controller and Constant voltage control a dual buck converter. Buck section The boost controller integrates a high current gate Integrated switching mosfets driver for an external n-channel mosfet. It delivers Lossless current sensing without need of a constant output voltage, up to 60 V, which external components supplies the inputs of the two integrated or external buck converters. Very accurate LED current setting programming inductor s peak current and The boost controller of two devices can be peak-to-peak current ripple stacked, in order to operate in dual phase for high Adjustable peak current by SPI power applications, with an interleaving pattern Adjustable current ripple by SPI for an improved input current ripple. Integrated PWM generation unit with 10-bit The buck converters integrate n-channel mosfet resolution and phase shift which is driven by a bootstrap circuit. July 2018 DS11130 Rev 5 1/73 This is information on a product in full production. www.st.comContents L99LD21 Contents 1 Introduction 8 1.1 Typical application . 9 2 Boost controller 13 2.1 General description . 13 2.2 Frequency selection . 13 2.3 Output voltage setting . 13 2.4 Overvoltage protection . 13 2.5 Feedback failure protection . 14 2.6 Operation in dual phase interleaved mode 14 2.7 Soft start 16 2.8 Slope compensation . 16 2.9 Operation together with the buck converters 16 3 Buck converters . 18 3.1 General description . 18 3.2 Bootstrap circuit 18 3.3 Peak and average current setting 18 3.4 Buck converters blank time . 20 3.5 Buck converters start-up . 21 3.6 Switching frequency . 21 4 Functional description 22 4.1 Operating modes . 22 4.1.1 Standby mode 22 4.1.2 Pre-standby mode . 23 4.1.3 Reset mode 23 4.1.4 Limp home . 23 4.1.5 Active mode 24 4.2 Programmable functions . 25 4.2.1 Activation of the buck output . 25 4.2.2 PWM dimming 25 2/73 DS11130 Rev 5