ZXLD1371 Green 60V HIGH ACCURACY BUCK/BOOST/BUCK-BOOST LED DRIVER-CONTROLLER Description Pin Assignments The ZXLD1371 is an LED driver controller IC for driving external TSSOP-16EP MOSFETs to drive high-current LEDs. It is a multi-topology controller enabling it to efficiently control the current through series connected ADJ 1 16 GI LEDs. The multi-topology enables it to operate in buck, boost and REF PWM 2 15 buck-boost configurations. TADJ 3 14 FLAG The 60V capability coupled with its multi-topology capability enables it SHP ISM 4 13 to be used in a wide range of applications and drive in excess of 15 STATUS 5 12 VIN LEDs in series. SGND 6 11 VAUX The ZXLD1371 is a modified hysteretic controller using a patent PGND GATE 7 10 pending control scheme providing high output current accuracy in all 8 9 N/C N/C three modes of operation. High accuracy dimming is achieved through DC control and high frequency PWM control. The ZXLD1371 uses two pins for fault diagnosis. A flag output highlights a fault, while the multi-level status pin gives further information on the exact fault. Features Typical Application Circuit VIN 8V to 22V 1 to 6 ILED = 1A 0.5% typical output current accuracy LEDs R1 5 to 60V operating voltage range 0R05 L1 LED driver supports Buck, Boost and Buck-boost 33H D1 VAUX VIN ISM C1 configurations PDS3100 PWM 10F Wide dynamic range dimming GI RGI2 GATE ADJ ZXLD1371 o 10:1 DC dimming 75k Q1 C OUT FLAG DMN6068LK3 REF 10F o 1000:1 dimming range at 500Hz STATUS R4 TADJ Up to 1MHz switching SHP NC SGND PGND 1.8k High temperature control of LED current using T ADJ C2 RGI1 TH1 330pF Available in Automotive Grade with AEC-Q100 and TS16949 24k 10k Thermally connected certification Lead-Free Finish RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) Buck-Boost Diagram Utilizing Thermistor and T ADJ An Automotive-Compliant Part is Available Under Separate ILED Datasheet (ZXLD1371Q) REF Rth 100% TADJ TH1 10% 70C 85C TLED Thermal network response in Buck configuration with: Rth = 1.8k and TH1=10k (beta =3900) Curve Showing LED Current vs. T LED Notes: 1. EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. All applicable RoHS exemptions applied. 2. See ZXLD1371 Pin Descriptions Type Pin Name Pin Description (Note 4) Adjust input (for DC output current control) Connect to REF to set 100% output current. Drive with DC voltage (125mV<V < 1.25V) to adjust output current from 10% to 100% of set ADJ 1 I ADJ value. The ADJ pin has an internal clamp that limits the internal node to less than 3V. This provides some failsafe should they get overdriven Internal 1.25V reference voltage output REF 2 O Temperature Adjust input for LED thermal current control Connect thermistor/resistor network to this pin to reduce output current above a preset temperature TADJ 3 I threshold. Connect to REF to disable thermal compensation function. (See section on thermal control.) Shaping capacitor for feedback control loop SHP 4 I/O Connect 330pF 20% capacitor from this pin to ground to provide loop compensation Operation status output (analog output) Pin is at 4.5V (nominal) during normal operation. Pin switches to a lower voltage to indicate specific operation warnings or fault conditions. (See STATUS 5 O section on STATUS output.) Status pin voltage is low during shutdown mode Signal ground (Connect to 0V) SGND 6 P Power ground - Connect to 0V and pin 8 to maximize copper area PGND 7 P Not Connected internally recommend connection to pin 7, (PGND), to maximize PCB copper for N/C 8 - thermal dissipation Not Connected internally recommend connection pin 10 (GATE) to permit wide copper trace to N/C 9 gate of MOSFET Gate drive output to external NMOS transistor connect to pin 9 GATE 10 O Auxiliary positive supply to internal switch gate driver At V < 8V a bootstrap circuit is recommended to ensure adequate gate drive voltage IN (see Applications section) At V > 8V connect to V V 11 P IN IN AUX At V >24V to reduce power dissipation, V can be connected to an 8V to 15V auxiliary power IN AUX supply (see Applications section). Decouple to ground with capacitor close to device (see Applications section) Input supply to device 5V to 60V V 12 P IN Decouple to ground with capacitor close to device (refer to Applications section) Current monitor input. Connect current sense resistor between this pin and V IN The nominal voltage, V , across the resistor is 218mV fixed in Buck mode and initially 225mV SENSE ISM 13 I in Boost and Buck-Boost modes, varying with duty cycle. Flag open drain output Pin is high impedance during normal operation FLAG 14 O Pin switches low to indicate a fault, or warning condition Digital PWM output current control Pin driven either by open Drain or push-pull 3.3V or 5V logic levels. Drive with frequency higher than 100Hz to gate output on and off during dimming c ontrol. PWM 15 I The device enters standby mode when PWM pin is driven with logic low level for more than 15ms nominal (Refer to application section for more details) Gain setting input Used to set the device in Buck mode or Boost, Buck-boost modes and to control the sense voltage in Boost and Buck-boost modes Connect to ADJ pin for Buck mode operation GI 16 I For Boost and Buck-boost modes, connect to resistive divider from ADJ to SGND. The GI divider is required to compensate for duty cycle gating in the internal feedback loop (see Application section). The GI pin has an internal clamp that limits the internal node to less than 3V. This provides some failsafe should it become overdriven. Exposed pad. Connect to 0V plane for electrical and thermal management. EP PAD P Note: 4. Type refers to whether or not pin is an Input, Output, Input/Output or Power supply pin. 2 of 43 ZXLD1371 February 2017 Diodes Incorporated www.diodes.com Document number: DS35436 Rev. 2 - 2