TPS92610QPWPRQ1

Product Folder Order Now Support & Community Tools & Software Technical Documents Reference Design TPS92610-Q1 SLDS233B – OCTOBER 2017 – REVISED JANUARY 2020 TPS92610-Q1 Automotive Single-Channel Linear LED Driver 1 Features 2 Applications • • • 1 • • • • • • • • • • Qualified for Automotive Applications AEC-Q100 Qualified With the Following Results: – Temperature Grade 1: –40°C to 125°C Ambient Operating Temperature Range – Device HBM ESD Classification Level H2 – Device CDM ESD Classification Level C3B Functional safety capable – Documentation available to aid functional safety system design Single-Channel Constant-Current LED Driver With PWM Dimming Wide Input-Voltage Range: 4.5 V–40 V Constant Output Current, Adjustable by Sense Resistor Precision Current Regulation, Tolerance ±4.6% Across Junction Temperature –40°C to 150°C Maximum Current: 450 mA Heat Sharing With External Resistor Low Dropout Voltage (Sense–Resistor Voltage Drop Included) – Maximum Dropout: 150 mV at 10 mA – Maximum Dropout: 400 mV at 70 mA – Maximum Dropout: 700 mV at 150 mA – Maximum Dropout: 1.3 V at 300 mA Diagnostics and Protection – Single-LED Short-Circuit Detection With AutoRecovery – LED Open-Circuit and Short-Circuit Detection With Auto-Recovery – Diagnostic-Enable With Adjustable Threshold for Low-Dropout Operation – Fault Bus up to 15 Devices, Configurable As Either One-Fails–All-Fail or Only-FailedChannel-Off – Low Quiescent Current and Fault-Mode Current ( V(SSH_th) SSL + R2 R1 – VSSL < V(SSL_th) + V(SSL_th) – Copyright © 2017, Texas Instruments Incorporated Figure 20. Single-LED Short Detection 12 Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: TPS92610-Q1 TPS92610-Q1 www.ti.com SLDS233B – OCTOBER 2017 – REVISED JANUARY 2020 Feature Description (continued) Use the following equation to calculate the ratio of R1 and R2. R 2 = (N o. of LE D s - 1) ´ R 1 (2) By using the resistor divider with values calculated in Equation 2, the voltages of SSH and SSL are then equal to the forward voltage of a single LED. With built-in comparators, the device can report failure if any of the LEDs is shorted within this string. An internal resistor string on SSL and resistors R1 and R2 draw current from OUT. TI recommends total resistance of R1 and R2 greater than 100-kΩ, so the current has negligible effect on LED luminance. Even within the same batch of LEDs, the LED forward voltage may vary from one to another. Taking account of forward voltage differences is necessary to avoid any false faults. 4.5 ± 40V 4.5 ± 40V TPS92610 ± Q1 EN EN TPS92610 ± Q1 EN SUPPLY EN SUPPLY R(SNS) DIAGEN PWM DIAGEN PWM R(SNS) DIAGEN IN PWM OUT DIAGEN IN PWM OUT FAULT SSH GND SSL R2 FAULT FAULT SSH GND SSL R2 FAULT R1 GND GND R1 Copyright © 2017, Texas Instruments Incorporated Figure 21. Bypass Single-LED Short Detection Copyright © 2017, Texas Instruments Incorporated Figure 22. With Single-LED Short Detection 7.3.5.6 Overtemperature Protection The TPS92610-Q1 device monitors device junction temperature. When the junction temperature reaches thermal shutdown threshold T(TSD), the output shuts down. Once the junction temperature falls below T(TSD) – T(TSD_HYS), the device resumes normal operation. During overtemperature protection, the FAULT bus is pulled low. 7.3.6 FAULT Bus Output With One-Fails–All-Fail The TPS92610-Q1 device has a FAULT bus for diagnostics output. In normal operation, FAULT is weakly pulled up by an internal pullup current source I(FAULT_pullup) higher than VOH(FAULT). If any fault scenario occurs, the FAULT bus is strongly pulled low by the internal pulldown current source I(FAULT_pulldown). Once V(FAULT) falls below VIL(FAULT), all outputs shut down for protection. The faulty channel keeps retrying until the fault scenario is removed. If FAULT is externally pulled up with a current larger than I(FAULT_pulldown), the one-fails–all-fail function is disabled and only the faulty channel is turned off. The FAULT bus is able to support up to 15 pieces of TPS9261x-Q1, TPS9263x-Q1, or TPS9283x-Q1 devices. Submit Documentation Feedback Copyright © 2017–2020, Texas Instruments Incorporated Product Folder Links: TPS92610-Q1 13 TPS92610-Q1 SLDS233B – OCTOBER 2017 – REVISED JANUARY 2020 www.ti.com Feature Description (continued) Table 1. Fault Table With DIAGEN = HIGH FAULT BUS STATUS FAULT TYPE DETECTION MECHANISM FAULT floating or externally pulled up Open-circuit or short-to-supply V(IN) – V(OUT) < V(OPEN_th_rising) CHANNEL STATE DEGLITCH TIME FAULT BUS FAULT HANDLING ROUTINE FAULT RECOVERY On t(OPEN_deg) Constantcurrent pulldown Device works normally with FAULT pin pulled low. Device sources I(retry) current when PWM is LOW. Device keeps output normal when PWＭ is HIGH. Auto recover Short-to-ground V(OUT) < V(SG_th_rising) On t(SG_deg) Constantcurrent pulldown Device turns output off and retries with constant current I(retry), ignoring the PWM input. Auto recover Single-LED short On t(SS_deg) Constantcurrent pulldown Device turns output off and retry with constant current I(retry), ignoring the PWM input. Auto recover On or off t(TSD_deg) Constantcurrent pulldown Devices turns output off. Auto recover V(SSL) – V(SSH) > V(SS_th) or V(SSL) < V(SSL_th) Overtemperatur TJ > T(TSD) e Externally pulled low Device turns output off Table 2. Fault Table With DIAGEN = LOW FAULT BUS STATUS FAULT TYPE FAULT floating or externally pulled up Open-circuit or short-to-supply DETECTION MECHANISM Short-to-ground VOUT < V(SG_th_rising) CHANNEL STATE DEGLITCH TIME FAULT HANDLING ROUTINE FAULT RECOVERY Ignored On t(SG_deg) Single-LED short Overtemperatur TJ > T(TSD) e FAULT BUS Constantcurrent pulldown Device turns output off and retries with constant current I(retry), ignoring the PWM input. Auto recover Device turns output off. Auto recover Ignored On or off Externally pulled low t(TSD_deg) Constantcurrent pulldown Device turns output off 7.4 Device Functional Modes 7.4.1 Undervoltage Lockout, V(SUPPLY)