Datasheet · 2016

TI TPS2552 / TPS2553 Precision Adjustable Current-Limited Power-Distribution Switches — Datasheet (SLVS841F)

Precision current-limited USB power switch, up to 1.5 A.

Author: Texas Instruments
Year: 2016
Type: Datasheet
Credit: Texas Instruments (ti.com)

usb
current limit
power switch

Sample & Buy Product Folder Support & Community Tools & Software Technical Documents Reference Design TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 TPS255xx Precision Adjustable Current-Limited Power-Distribution Switches 1 Features 3 Description • • • • The TPS255x and TPS255x-1 power-distribution switches are intended for applications where precision current limiting is required or heavy capacitive loads and short circuits are encountered and provide up to 1.5 A of continuous load current. These devices offer a programmable current-limit threshold between 75 mA and 1.7 A (typical) through an external resistor. Current-limit accuracy as tight as ±6% can be achieved at the higher current-limit settings. The power-switch rise and fall times are controlled to minimize current surges during turnon and turnoff. 1 • • • • • • • • • • Up to 1.5-A Maximum Load Current ±6% Current-Limit Accuracy at 1.7 A (Typical) Meets USB Current-Limiting Requirements Backwards Compatible With TPS2550 and TPS2551 Adjustable Current Limit: 75 mA to 1700 mA (Typical) Constant-Current (TPS255x) and Latch-Off (TPS255x-1) Versions Fast Overcurrent Response - 2 µs (Typical) 85-mΩ High-Side MOSFET (DBV Package) Reverse Input-Output Voltage Protection Operating Range: 2.5 V to 6.5 V Built-In Soft Start 15-kV ESD Protection per IEC 61000-4-2 (With External Capacitance) UL Listed – File No. E169910 and NEMKO IEC60950-1-am1 ed2.0 See the TI Switch Portfolio TPS255x devices limit the output current to a safe level by using a constant-current mode when the output load exceeds the current-limit threshold. TPS255x-1 devices provide circuit breaker functionality by latching off the power switch during overcurrent or reverse-voltage situations. An internal reverse-voltage comparator disables the powerswitch when the output voltage is driven higher than the input to protect devices on the input side of the switch. The FAULT output asserts low during overcurrent and reverse-voltage conditions. Device Information(1) 2 Applications • • • • PART NUMBER USB Ports and Hubs Digital TVs Set-Top Boxes VOIP Phones TPS2552 TPS2553 PACKAGE BODY SIZE (NOM) SOT-23 (6) 2.90 mm x 1.60 mm WSON (6) 2.00 mm x 2.00 mm SOT-23 (6) 2.90 mm x 1.60 mm WSON (6) 2.00 mm x 2.00 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Typical Application TPS2552/53 5V USB Input USB Data 0.1 mF IN OUT USB Port RFAULT 100 kW 120 mF Fault Signal Control Signal FAULT EN ILIM GND Power Pad RILIM 20 kW USB requirement only* *USB requirement that downstream facing ports are bypassed with at least 120 mF per hub Copyright © 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. 1 Applications ........................................................... 1 Description ............................................................. 1 Revision History..................................................... 2 Device Comparison Table..................................... 4 Pin Configuration and Functions ......................... 5 Specifications......................................................... 5 7.1 7.2 7.3 7.4 7.5 7.6 8 9 Absolute Maximum Ratings ...................................... 5 ESD Ratings ............................................................ 6 Recommended Operating Conditions....................... 6 Thermal Information .................................................. 6 Electrical Characteristics........................................... 7 Typical Characteristics .............................................. 8 Parameter Measurement Information ................ 11 Detailed Description ............................................ 13 9.1 9.2 9.3 9.4 9.5 Overview ................................................................. 13 Functional Block Diagram ....................................... 13 Feature Description................................................. 13 Device Functional Modes........................................ 15 Programming........................................................... 15 10 Application and Implementation........................ 17 10.1 Application Information.......................................... 17 10.2 Typical Applications .............................................. 17 11 Power Supply Recommendations ..................... 24 11.1 Self-Powered and Bus-Powered Hubs ................. 24 11.2 Low-Power Bus-Powered and High-Power BusPowered Functions .................................................. 24 11.3 Power Dissipation and Junction Temperature ...... 24 12 Layout................................................................... 25 12.1 Layout Guidelines ................................................. 25 12.2 Layout Example .................................................... 25 13 Device and Documentation Support ................. 26 13.1 13.2 13.3 13.4 13.5 13.6 13.7 Device Support...................................................... 26 Related Links ........................................................ 26 Receiving Notification of Documentation Updates 26 Community Resources.......................................... 26 Trademarks ........................................................... 26 Electrostatic Discharge Caution ............................ 26 Glossary ................................................................ 26 14 Mechanical, Packaging, and Orderable Information ........................................................... 26 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision E (February 2012) to Revision F Page • Added ESD Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ................................................................................................. 1 • Changed 1300 mA to 1700 mA in the adjustable current limit bullet under the Features section ......................................... 1 • Changed from 1.2 A to 1.5 A.................................................................................................................................................. 4 Changes from Revision D (June 2011) to Revision E Page • Changed VEN to VEN in Recommended Operating Conditions ............................................................................................... 6 • Changed VEN to VEN in Recommended Operating Conditions ............................................................................................... 6 Changes from Revision C (September 2009) to Revision D Page • Changed From: Fast Overcurrent Response - 2-µS (typ) To: Fast Overcurrent Response - 2-µs (typ) in the Features ...... 1 • Added text To Feature - UL Listed "and NEMKO IEC60950-1-am1 ed2.0"........................................................................... 1 • Added Features Item "See the TI Switch Portfoilo"................................................................................................................ 1 • Changed the DEVICE INFORMATION table, and Deleted Note 3 ........................................................................................ 1 • Added ESD-system level (contact/air) to the ABS MAX table, and Added Note 3 ................................................................ 6 • Added text to the REVERSE-VOLTAGE PROTECTION section: "A reverse.....when this occurs.".................................... 14 2 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 Changes from Revision B (February 2009) to Revision C Page • Added Feature - Up to 1.5 A Maximum Load Current............................................................................................................ 1 • Changed 1.3 A (typ) To: 1.7 A (typ) ....................................................................................................................................... 1 • Added Text - and provide up to 1.5 A of continuous load current.......................................................................................... 1 • Changed From: 19.1 kΩ ≤ RILIM ≤ 232 kΩ To: 15 kΩ ≤ RILIM ≤ 232 kΩ. ................................................................................. 5 • Changed IOUT values for 1.2A and 1.5A ................................................................................................................................. 6 • Changed TJ values for 1.2A and 1.5A .................................................................................................................................... 6 • Added RILIM = 15 kΩ option .................................................................................................................................................... 7 • Changed Text From: current-limit threshold between 75 mA and 1.3 A (typ) To: current-limit threshold between 75 mA and 1.7 A (typ)................................................................................................................................................................ 13 • Changed Text From: The recommended 1% resistor range for RILIM is 19.1 kΩ ≤ RILIM ≤ 232 kΩ to ensure stability To: The recommended 1% resistor range for RILIM is 15 kΩ ≤ RILIM ≤ 232 kΩ to ensure stability........................................ 15 • Changed From: where 19.1 kΩ ≤ RILIM ≤ 232 kΩ. To: where 15 kΩ ≤ RILIM ≤ 232 kΩ. ........................................................ 15 • Changed Figure 23 - Current-Limit Threshold vs RILIM ........................................................................................................ 16 • Changed Table 2 - added rows for Current Limit of 1400 to 1700....................................................................................... 19 Changes from Revision A (December 2008) to Revision B Page • Added To Features - UL Listed – File No. E169910 .............................................................................................................. 1 • Changed Figure 17 Ttitle From: Current Limit Threshold Vs RILM ......................................................................................... 9 • Changed Figure 18 Ttitle From: Current Limit Threshold Vs RILM ......................................................................................... 9 Changes from Original (November 2008) to Revision A • Page Changed Title from: Adjustable Current-Limited Power-Distribution Switches to: Precision Adjustable CurrentLimited Power-Distribution Switches ...................................................................................................................................... 1 Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 3 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com 5 Device Comparison Table 4 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 6 Pin Configuration and Functions TPS255x DBV Package 6-Pin SOT-23 Top View 6 5 4 1 2 3 IN GND EN TPS255x DRV Package 6-Pin WSON Top View OUT ILIM FAULT 6 IN 1 2 PAD 5 GND 3 4 EN OUT ILIM FAULT EN = Active Low for the TPS2552 EN = Active Low for the TPS2552 EN = Active High for the TPS2553 EN = Active High for the TPS2553 Add –1 to part number for latch-off version Add –1 to part number for latch-off version Pin Functions PIN NAME TPS2552 SOT-23 TPS2553 I/O WSON SOT-23 WSON DESCRIPTION EN 3 4 — — I Enable input, logic low turns on power switch EN — — 3 4 I Enable input, logic high turns on power switch FAULT 4 3 4 3 O Active-low open-drain output, asserted during overcurrent, overtemperature, or reverse-voltage conditions. GND 2 5 2 5 — Ground connection; connect externally to PowerPAD ILIM 5 2 5 2 O External resistor used to set current-limit threshold; recommended 15 kΩ ≤ RILIM ≤ 232 kΩ. IN 1 6 1 6 I Input voltage; connect a 0.1 µF or greater ceramic capacitor from IN to GND as close to the IC as possible. OUT 6 1 6 1 O Power-switch output PowerPAD™ — PAD — PAD — Internally connected to GND; used to heat-sink the part to the circuit board traces. Connect PowerPAD to GND pin externally. Add –1 for Latch-Off version 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) (2) IO MIN MAX UNIT Voltage range on IN, OUT, EN or EN, ILIM, FAULT –0.3 7 V Voltage range from IN to OUT –7 7 V Continuous output current Internally Limited Continuous total power dissipation TJ Continuous FAULT sink current 0 25 mA ILIM source current 0 1 mA Maximum junction temperature –40 150 °C –65 150 °C Tstg Storage temperature (1) (2) See the Thermal Information Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Voltages are referenced to GND unless otherwise noted. Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 5 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com 7.2 ESD Ratings VALUE V(ESD) (1) (2) (3) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 Charged device model (CDM), per JEDEC specification JESD22C101 (2) ±500 IEC 61000-4-2 contact discharge (3) ±8000 IEC 61000-4-2 air-gap discharge (3) ±15000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. Surges per EN61000-4-2. 1999 applied to output terminals of EVM. These are passing test levels, not failure threshold. 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT VIN Input voltage, IN 2.5 6.5 V VEN Enable voltage TPS2552/52-1 0 6.5 V VEN Enable voltage TPS2553/53-1 0 6.5 V VIH High-level input voltage on EN or EN VIL Low-level input voltage on EN or EN IOUT Continuous output current, OUT RILIM IO 1.1 0.66 –40 °C ≤ TJ ≤ 125 °C 0 1.2 –40 °C ≤ TJ ≤ 105 °C 0 1.5 Current-limit threshold resistor range (nominal 1%) from ILIM to GND 15 232 kΩ Continuous FAULT sink current 0 10 mA Input de-coupling capacitance, IN to GND Operating virtual junction temperature (1) TJ (1) V 0.1 A µF IOUT ≤ 1.2 A –40 125 IOUT ≤ 1.5 A –40 105 °C See Power Dissipation and Junction Temperature for details on how to calculate maximum junction temperature for specific applications and packages. 7.4 Thermal Information TPS2552 THERMAL METRIC (1) TPS2553 DBV (SOT-23) DRV (WSON) DBV (SOT-23) DRV (WSON) 6 PINS 6 PINS 6 PINS 6 PINS UNIT RθJA Junction-to-ambient thermal resistance 182.6 72 182.6 72 °C/W RθJC(to Junction-to-case (top) thermal resistance 122.2 85.3 122.2 85.3 °C/W RθJB Junction-to-board thermal resistance 29.4 41.3 29.4 41.3 °C/W ψJT Junction-to-top characterization parameter 20.8 1.7 20.8 1.7 °C/W ψJB Junction-to-board characterization parameter 28.9 41.7 28.9 41.7 °C/W RθJC(b Junction-to-case (bottom) thermal resistance — 11.1 — 11.1 °C/W p) ot) (1) 6 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 7.5 Electrical Characteristics over recommended operating conditions, VEN = 0 V, or VEN = VIN, RFAULT = 10 kΩ (unless otherwise noted) TEST CONDITIONS (1) PARAMETER MIN TYP MAX UNIT POWER SWITCH DBV package, TJ = 25°C 85 DBV package, –40°C ≤TJ ≤125°C rDS(on) Static drain-source on-state resistance DRV package, TJ = 25°C 100 DRV package, –40°C ≤TJ ≤105°C Rise time, output tf Fall time, output 115 mΩ 140 DRV package, –40°C ≤TJ ≤125°C tr 95 135 150 CL = 1 µF, RL = 100 Ω, (see Figure 20) VIN = 6.5 V 1.1 VIN = 2.5 V 0.7 1.5 CL = 1 µF, RL = 100 Ω, (see Figure 20) VIN = 6.5 V 0.2 0.5 VIN = 2.5 V 0.2 0.5 0.66 1.1 V –0.5 0.5 µA 1 ms ENABLE INPUT EN OR EN Enable pin turn on/off threshold IEN Input current VEN = 0 V or 6.5 V, VEN = 0 V or 6.5 V ton Turnon time CL = 1 µF, RL = 100 Ω, (see Figure 20) 3 ms toff Turnoff time CL = 1 µF, RL = 100 Ω, (see Figure 20) 3 ms CURRENT LIMIT RILIM = 15 kΩ, –40°C ≤TJ ≤105°C Current-limit threshold (Maximum DC output current IOUT delivered to load) and Short-circuit current, OUT connected to GND IOS tIOS Response time to short circuit 1610 1700 1800 TJ = 25°C 1215 1295 1375 –40°C ≤TJ ≤125°C 1200 1295 1375 TJ = 25°C 490 520 550 –40°C ≤TJ ≤125°C 475 520 565 RILIM = 210 kΩ 110 130 150 ILIM shorted to IN 50 75 100 RILIM = 20 kΩ RILIM = 49.9 kΩ VIN = 5 V (see Figure 21) 2 mA µs REVERSE-VOLTAGE PROTECTION Reverse-voltage comparator trip point (VOUT – VIN) Time from reverse-voltage condition to MOSFET turn off VIN = 5 V 95 135 190 mV 3 5 7 ms SUPPLY CURRENT IIN_off Supply current, low-level output VIN = 6.5 V, No load on OUT, VEN = 6.5 V or VEN = 0 V 0.1 1 µA RILIM = 20 kΩ 120 140 µA RILIM = 210 kΩ 100 120 µA TJ = 25 °C 0.01 1 µA VIN rising 2.35 2.45 TJ = 25 °C 25 IIN_on Supply current, high-level output VIN = 6.5 V, No load on OUT IREV Reverse leakage current VOUT = 6.5 V, VIN = 0 V UNDERVOLTAGE LOCKOUT UVLO Low-level input voltage, IN Hysteresis, IN V mV FAULT FLAG VOL Output low voltage, FAULT I/FAULT = 1 mA 180 Off-state leakage V/FAULT = 6.5 V 1 µA FAULT deglitch mV FAULT assertion or de-assertion due to overcurrent condition 5 7.5 10 ms FAULT assertion or de-assertion due to reverse-voltage condition 2 4 6 ms THERMAL SHUTDOWN Thermal shutdown threshold 155 °C Thermal shutdown threshold in current-limit 135 °C Hysteresis (1) 10 °C Pulse-testing techniques maintain junction temperature close to ambient temperature; thermal effects must be taken into account separately. Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 7 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com 7.6 Typical Characteristics Figure 1. Turnon Delay and Rise Time Figure 2. Turnoff Delay and Fall Time 8 Figure 3. Device Enabled into Short-Circuit Figure 4. Full-Load to Short-Circuit Transient Response Figure 5. Short-Circuit to Full-Load Recovery Response Figure 6. No-Load to Short-Circuit Transient Response Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 Typical Characteristics (continued) Figure 7. Short-Circuit to No-Load Recovery Response Figure 8. No Load to 1-Ω Transient Response Figure 10. Reverse-Voltage Protection Response Figure 9. 1-Ω to No Load Transient Response 2.40 RILIM = 20 kW UVLO - Undervoltage Lockout - V 2.39 2.38 2.37 UVLO Rising 2.36 2.35 2.34 UVLO Falling 2.33 2.32 2.31 2.30 -50 Figure 11. Reverse-Voltage Protection Recovery Copyright © 2008–2016, Texas Instruments Incorporated 0 50 TJ - Junction Temperature - °C 100 150 Figure 12. UVLO – Undervoltage Lockout – V Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 9 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com Typical Characteristics (continued) 150 0.40 RILIM = 20 kW 135 IIN - Supply Current, Output Enabled - mA IIN - Supply Current, Output Disabled - mA 0.36 0.32 0.28 0.24 VIN = 6.5 V 0.20 0.16 0.12 0.08 VIN = 2.5 V 0 50 TJ - Junction Temperature - °C 100 105 90 75 VIN = 3.3 V VIN = 2.5 V 60 45 30 0 -50 150 Figure 13. IIN – Supply Current, Output Disabled – µA 0 50 TJ - Junction Temperature - °C 100 150 Figure 14. IIN – Supply Current, Output Enabled – µA 150 rDS(on) - Static Drain-Source On-State Resistance - mW 20 VIN = 5 V, 18 RILIM = 20 kW, TA = 25°C 16 Current Limit Response - ms VIN = 5 V 15 0 -50 14 12 10 8 6 4 2 125 DRV Package 100 DBV Package 75 50 25 0 -50 0 0 1.5 3 Peak Current - A 4.5 0 6 Figure 15. Current Limit Response – µs 50 TJ - Junction Temperature - °C 100 150 Figure 16. MOSFET rDS(on) Vs. Junction Temperature 1400 150 1300 140 130 IDS - Static Drain-Source Current - mA 1200 IDS - Static Drain-Source Current - mA VIN = 6.5 V 120 0.04 TA = -40°C 1100 1000 TA = 25°C 900 TA = 125°C 800 700 600 500 400 300 200 VIN = 6.5 V, 100 RILIM = 20 kW 0 0 100 200 300 400 500 600 VIN - VOUT - 100 mV/div 700 800 900 1000 Figure 17. Switch Current Vs. Drain-Source Voltage Across Switch 10 RILIM = 20 kW Submit Documentation Feedback 120 TA = 25°C TA = -40°C 110 TA = 125°C 100 90 80 70 60 50 40 30 20 VIN = 6.5 V, 10 RILIM = 200 kW 0 0 100 200 300 400 500 600 VIN - VOUT - 100 mV/div 700 800 900 1000 Figure 18. Switch Current Vs. Drain-Source Voltage Across Switch Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 8 Parameter Measurement Information TPS2552 10 mF VIN IN VOUT OUT RFAULT 10 kW 150 mF ILIM Fault Signal FAULT Control Signal RILIM GND EN Power Pad Figure 19. Typical Characteristics Reference Schematic OUT tf tr CL RL 90% 90% VOUT 10% 10% TEST CIRCUIT VEN 50% 50% VEN ton VOUT toff toff ton 90% 50% 50% toff 90% VOUT 10% 10% VOLTAGE WAVEFORMS Figure 20. Test Circuit and Voltage Waveforms IOS IOUT tIOS Figure 21. Response Time to Short-Circuit Waveform Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 11 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com Parameter Measurement Information (continued) Decreasing Load Resistance VOUT Decreasing Load Resistance IOUT IOS Figure 22. Output Voltage vs Current-Limit Threshold 12 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 9 Detailed Description 9.1 Overview The TPS255x and TPS255x-1 are current-limited, power-distribution switches using N-channel MOSFETs for applications where short circuits or heavy capacitive loads are encountered and provide up to 1.5 A of continuous load current. These devices allow the user to program the current-limit threshold between 75 mA and 1.7 A (typical) through an external resistor. Additional device shutdown features include overtemperature protection and reverse-voltage protection. The device incorporates an internal charge pump and gate drive circuitry necessary to drive the N-channel MOSFET. The charge pump supplies power to the driver circuit and provides the necessary voltage to pull the gate of the MOSFET above the source. The charge pump operates from input voltages as low as 2.5 V and requires little supply current. The driver controls the gate voltage of the power switch. The driver incorporates circuitry that controls the rise and fall times of the output voltage to limit large current and voltage surges and provides built-in soft-start functionality. There are two device families that handle overcurrent situations differently. The TPS255x family enters constant-current mode while the TPS255x-1 family latches off when the load exceeds the current-limit threshold. 9.2 Functional Block Diagram - Reverse Voltage Comparator + IN OUT 4-ms Deglitch CS Current Sense Charge Pump Driver EN Current Limit FAULT (Note A) UVLO GND Thermal Sense 8-ms Deglitch ILIM Copyright © 2016, Texas Instruments Incorporated A. TPS255x parts enter constant current mode during current limit condition; TPS255x-1 parts latch off 9.3 Feature Description 9.3.1 Overcurrent Conditions The TPS255x and TPS255x-1 respond to overcurrent conditions by limiting their output current to the IOS levels shown in Figure 23. When an overcurrent condition is detected, the device maintains a constant output current and reduces the output voltage accordingly. Two possible overload conditions can occur. The first condition is when a short circuit or partial short circuit is present when the device is powered-up or enabled. The output voltage is held near zero potential with respect to ground and the TPS255x ramps the output current to IOS. The TPS255x devices limits the current to IOS until the overload condition is removed or the device begins to thermal cycle. The TPS255x-1 devices will limit the current to IOS until the overload condition is removed or the internal deglitch time (7.5-ms typical) is reached and the device is turned off. The device remains off until power is cycled or the device enable is toggled. Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 13 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com Feature Description (continued) The second condition is when a short circuit, partial short circuit, or transient overload occurs while the device is enabled and powered on. The device responds to the overcurrent condition within time tIOS (see Figure 21). The current-sense amplifier is overdriven during this time and momentarily disables the internal current-limit MOSFET. The current-sense amplifier recovers and limits the output current to IOS. Similar to the previous case, the TPS255x limits the current to IOS until the overload condition is removed or the device begins to thermal cycle; the TPS255x-1 limits the current to IOS until the overload condition is removed or the internal deglitch time is reached and the device is latched off. The TPS255x thermal cycles if an overload condition is present long enough to activate thermal limiting in any of the above cases. The device turns off when the junction temperature exceeds 135°C (typical) while in current limit. The device remains off until the junction temperature cools 10°C (typical) and then restarts. The TPS255x cycles on and off until the overload is removed (see Figure 5 and Figure 7) . 9.3.2 Reverse-Voltage Protection The reverse-voltage protection feature turns off the N-channel MOSFET whenever the output voltage exceeds the input voltage by 135 mV (typical) for 4-ms (typical). A reverse current of (VOUT – VIN)/rDS(on)) are present when this occurs. This prevents damage to devices on the input side of the TPS255x and TPS2552-1/TPS2253-1 by preventing significant current from sinking into the input capacitance. The TPS255x devices allow the N-channel MOSFET to turn on once the output voltage goes below the input voltage for the same 4-ms deglitch time. The TPS255x-1 devices keep the device turned off even if the reverse-voltage condition is removed and do not allow the N-channel MOSFET to turn on until power is cycled or the device enable is toggled. The reverse-voltage comparator also asserts the FAULT output (active-low) after 4-ms. 9.3.3 FAULT Response The FAULT open-drain output is asserted (active low) during an overcurrent, overtemperature, or reverse-voltage condition. The TPS255x asserts the FAULT signal until the fault condition is removed and the device resumes normal operation. The TPS255x-1 asserts the FAULT signal during a fault condition and remains asserted while the part is latched-off. The FAULT signal is de-asserted once device power is cycled or the enable is toggled and the device resumes normal operation. The TPS255x and TPS255x-1 are designed to eliminate false FAULT reporting by using an internal delay de-glitch circuit for overcurrent (7.5-ms typical) and reverse-voltage (4-ms typical) conditions without the need for external circuitry. This ensures that FAULT is not accidentally asserted due to normal operation such as starting into a heavy capacitive load. The deglitch circuitry delays entering and leaving fault conditions. Overtemperature conditions are not deglitched and assert the FAULT signal immediately. 9.3.4 Undervoltage Lockout (UVLO) The undervoltage lockout (UVLO) circuit disables the power switch until the input voltage reaches the UVLO turnon threshold. Built-in hysteresis prevents unwanted on and off cycling due to input voltage drop from large current surges. 9.3.5 ENABLE (EN or EN) The logic enable controls the power switch, bias for the charge pump, driver, and other circuits to reduce the supply current. The supply current is reduced to less than 1-µA when a logic low is present on EN. A logic low input on EN or a logic high input on EN enables the driver, control circuits, and power switch. The enable input is compatible with both TTL and CMOS logic levels. 9.3.6 Thermal Sense The TPS255x and TPS255x-1 have self-protection features using two independent thermal-sensing circuits that monitor the operating temperature of the power switch and disable operation if the temperature exceeds recommended operating conditions. The TPS255x device operates in constant-current mode during an overcurrent conditions, which increases the voltage drop across power-switch. The power dissipation in the package is proportional to the voltage drop across the power switch, which increases the junction temperature during an overcurrent condition. The first thermal sensor turns off the power switch when the die temperature exceeds 135°C (minimum) and the part is in current limit. Hysteresis is built into the thermal sensor, and the switch turns on after the device has cooled approximately 10°C. 14 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 Feature Description (continued) The TPS255x and TPS255x-1 also have a second ambient thermal sensor. The ambient thermal sensor turns off the power-switch when the die temperature exceeds 155°C (minimum) regardless of whether the power switch is in current limit and turns on the power switch after the device has cooled approximately 10°C. The TPS255x and TPS255x-1 families continue to cycle off and on until the fault is removed. The open-drain fault reporting output FAULT is asserted (active low) immediately during an overtemperature shutdown condition. 9.4 Device Functional Modes There are no other functional modes. 9.5 Programming 9.5.1 Programming the Current-Limit Threshold The overcurrent threshold is user programmable through an external resistor. The TPS255x and TPS255x-1 use an internal regulation loop to provide a regulated voltage on the ILIM pin. The current-limit threshold is proportional to the current sourced out of ILIM. The recommended 1% resistor range for RILIM is 15 kΩ ≤ RILIM ≤ 232 kΩ to ensure stability of the internal regulation loop. Many applications require that the minimum current limit is above a certain current level or that the maximum current limit is below a certain current level, so it is important to consider the tolerance of the overcurrent threshold when selecting a value for RILIM. The following equations and Figure 23 can be used to calculate the resulting overcurrent threshold for a given external resistor value (RILIM). Figure 23 includes current-limit tolerance due to variations caused by temperature and process. However, the equations do not account for tolerance due to external resistor variation, so it is important to account for this tolerance when selecting RILIM. The traces routing the RILIM resistor to the TPS255x and TPS255x-1 must be as short as possible to reduce parasitic effects on the current-limit accuracy. RILIM can be selected to provide a current-limit threshold that occurs 1) above a minimum load current or 2) below a maximum load current. To design above a minimum current-limit threshold, find the intersection of RILIM and the maximum desired load current on the IOS(min) curve and choose a value of RILIM below this value. Programming the current limit above a minimum threshold is important to ensure start-up into full load or heavy capacitive loads. The resulting maximum current-limit threshold is the intersection of the selected value of RILIM and the IOS(max) curve. To design below a maximum current-limit threshold, find the intersection of RILIM and the maximum desired load current on the IOS(max) curve and choose a value of RILIM above this value. Programming the current limit below a maximum threshold is important to avoid current limiting upstream power supplies, causing the input voltage bus to droop. The resulting minimum current-limit threshold is the intersection of the selected value of RILIM and the IOS(min) curve. Current-Limit Threshold Equations (IOS): IOSmax (mA) = 22980V RILIM0.94kW IOSnom (mA) = 23950V RILIM0.977kW IOSmin (mA) = 25230V RILIM1.016kW where 15 kΩ ≤ RILIM ≤ 232 kΩ. (1) While the maximum recommended value of RILIM is 232 kΩ, there is one additional configuration that allows for a lower current-limit threshold. The ILIM pin may be connected directly to IN to provide a 75 mA (typical) currentlimit threshold. Additional low-ESR ceramic capacitance may be necessary from IN to GND in this configuration to prevent unwanted noise from coupling into the sensitive ILIM circuitry. Copyright © 2008–2016, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 15 TPS2552, TPS2553, TPS2552-1, TPS2553-1 SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 www.ti.com Programming (continued) 1800 1700 1600 Current Limit Threshold - mA 1500 1400 1300 1200 1100 1000 900 IOS(max) 800 700 600 IOS(nom) 500 400 300 IOS(min) 200 100 0 15 25 35 45 55 65 75 85 95 105 115 125 135 145 155 165 175 185 195 205 215 225 235 RILIM - Current Limit Resistor - kW Figure 23. Current-Limit Threshold vs RILIM 16 Submit Documentation Feedback Copyright © 2008–2016, Texas Instruments Incorporated Product Folder Links: TPS2552 TPS2553 TPS2552-1 TPS2553-1 TPS2552, TPS2553, TPS2552-1, TPS2553-1 www.ti.com SLVS841F – NOVEMBER 2008 – REVISED AUGUST 2016 10 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 10.1 Application Information 10.1.1 Constant-Current vs Latch-Off Operation and Impact on Output Voltage Both the constant-current devices (TPS255x) and latch-off devices (TPS255x-1) operate identically during normal operation, that is, the load current is less than the current-limit threshold and the devices are not limiting current. During normal operation the N-channel MOSFET is fully enhanced, and VOUT = VIN - (IOUT x rDS(on)). The voltage drop across the MOSFET is relatively small compared to VIN, and VOUT ≉ VIN. Both the constant-current devices (TPS255x ) and latch-off devices (TPS255x-1) operate identically during the initial onset of an overcurrent event. Both devices limit current to the programmed current-limit threshold set to RILIM by operating the N-channel MOSFET in the linear mode. During current-limit operation, the N-channel MOSFET is no longer fully-enhanced and the resistance of the device increases. This allows the device to effectively regulate the current to the current-limit threshold. The effect of increasing the resistance of the MOSFET is that the voltage drop across the device is no longer negligible (VIN ≠ VOUT), and VOUT decreases. The amount that VOUT decreases is proportional to the magnitude of the overload condition. The expected VOUT can be calculated by, IOS × RLOAD where IOS is the current-limit threshold and RLOAD is the magnitude of the overload condition. (2) For example, if IOS is programmed to 1 A and a 1 Ω overload condition is applied, the resulting VOUT is 1 V. While both the constant-current devices (TPS255x ) and latch-off devices (TPS255x-1) operate identically during the initial onset of an overcurrent event, they behave differently if the overcurrent event lasts longer than the internal delay de-glitch circuit (7.5-ms typical). The constant-current devices (TPS255x ) assert the FAULT flag after the deglitch period and continue to regulate the current to the current-limit threshold indefinitely. In practical circuits, the power dissipation in the package increases the die temperature above the overtemperature shutdown threshold (135°C minimum), and the device turns off until the die temperature decreases by the hysteresis of the thermal shutdown circuit (10°C typical). The device turns on and continues to thermal cycle until the overload condition is removed. The constant-current devices resume normal operation once the overload condition is removed. The latch-off devices (TPS255x-1) assert the FAULT flag after the deglitch period and immediately turn off the device. The device remains off regardless of whether the overload condition is removed from the output. The latch-off devices remain off and do not resume normal operation until the surrounding system either toggles the enable or cycles power to the device. 10.2 Typical Applications 10.2.1 Two-Level Current-Limit Circuit Some applications require different current-limit thresholds depending on external system conditions. Figure 24 shows an implementation for an externally controlled, two-level current-limit circuit. The current-limit threshold is set by the total resistance from ILIM to GND (see the Programming the Current-Limit Threshold section). A logiclevel input enables or disables MOSFET Q1