• Menu
  • Product
  • Email
  • PDF
  • Order now

  • TPS65279 4.5- to 18-V Input, 5-A/5-A Dual Synchronous Step-Down Converter With Current Sharing

    • SLVSC85C August   2013  – May 2015 TPS65279

      PRODUCTION DATA.  

  • CONTENTS
  • SEARCH
  • TPS65279 4.5- to 18-V Input, 5-A/5-A Dual Synchronous Step-Down Converter With Current Sharing
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Enable and Adjusting Undervoltage Lockout (UVLO)
      2. 8.3.2 Adjustable Switching Frequency and Synchronization
        1. 8.3.2.1 Synchronization
      3. 8.3.3 Soft-Start Time
      4. 8.3.4 Out-of-Phase Operation
      5. 8.3.5 Output Overvoltage Protection (OVP)
      6. 8.3.6 Bootstrap Voltage (BOOT) and Low Dropout Operation
      7. 8.3.7 Overcurrent Protection
        1. 8.3.7.1 High-Side MOSFET Overcurrent Protection
        2. 8.3.7.2 Low-Side MOSFET Overcurrent Protection
      8. 8.3.8 Current Sharing Operation
      9. 8.3.9 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 CCM Operation Mode
      2. 8.4.2 PSM Operation Mode
      3. 8.4.3 Current Sharing Mode
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Dual Buck Operation Mode Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Adjusting the Output Voltage
          2. 9.2.1.2.2 Adjusting UVLO
          3. 9.2.1.2.3 Adjustable Switching Frequency (Resistor Mode)
          4. 9.2.1.2.4 Output Inductor Selection
          5. 9.2.1.2.5 Output Capacitor Selection
          6. 9.2.1.2.6 Input Capacitor Selection
          7. 9.2.1.2.7 Loop Compensation
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Current Sharing Mode Operation Application
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Community Resources
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
  14. IMPORTANT NOTICE

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
  • DAP|32
    • MPDS380A
  • RHH|36
    • MPQF144E
サーマルパッド・メカニカル・データ
  • DAP|32
    • PPTD257A
  • RHH|36
    • QFND054L
発注情報
  • slvsc85c_oa
  • slvsc85c_pm
search No matches found.
  • Full reading width
    • Full reading width
    • Comfortable reading width
    • Expanded reading width
  • Card for each section
  • Card with all content

 

DATA SHEET

TPS65279 4.5- to 18-V Input, 5-A/5-A Dual Synchronous Step-Down Converter With Current Sharing

1 Features

  • 4.5-V to 18-V Wide Input Voltage Range
  • Programmable Slew Rate Control for Output Voltage Transition
  • Up to 5-A Maximum Continuous Output Current in Buck 1 and Buck 2
  • Buck 1 and Buck 2 can be Paralleled to Deliver up to 10-A Current
  • Pulse Skipping Mode to Achieve High Efficiency in Light Load
  • Adjustable Switching Frequency
    200 kHz to 1.6 MHz Set by External Resistor
  • Dedicated Enable and Soft-Start for Each Buck
  • Peak Current-Mode Control With Simple Compensation Circuit
  • Cycle-by-Cycle Overcurrent Protection
  • 180° Out-of-Phase Operation to Reduce Input Capacitance and Power Supply Induced Noise
  • Over Temperature Protection
  • Available in 32-Pin Thermally Enhanced HTSSOP (DAP) and 36-Pin VQFN 6-mm × 6-mm (RHH) Packages

2 Applications

  • DTV
  • Telecom and Network
  • Point-of-Load
  • Set Top Boxes
  • Tablet PC

3 Description

TPS65279 is a monolithic dual synchronous buck converter with wide 4.5-V to 18-V operating input voltage range that encompassed most intermediate bus voltage operating off 5-, 9-, 12- or 15-V power bus or battery. The converter with constant frequency peak current mode control is designed to simplify its application while giving the designers options to optimize their usage according to the target applications.

Two bucks in TPS65279 can be paralleled to delivery up to 10-A load current by using current sharing mode, connect ISHARE pin high. Two phase operation in current sharing reduces system filtering capacitance and inductance, alleviates EMI and improves output voltage ripple and noise.

TPS65279 features a dedicated enable pin. An independent soft-start pin provides flexibility in power up programmability. Constant frequency peak current mode control simplifies the compensation and provides fast transient response. Cycle-by-cycle overcurrent protection and hiccup mode operation limit MOSFET power dissipation in short circuit or over loading fault conditions.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
TPS65279 HTSSOP (32) 6.20 mm × 11.00 mm
VQFN (36) 6.00 mm × 6.00 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Schematic

TPS65279 typ_app_mini_slvsc85.gif

Efficiency vs Loading

TPS65279 C009_slvsc85.gif

4 Revision History

Changes from B Revision (December 2013) to C Revision

  • Added ESD Ratings 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 Go
  • Updated conditions for Electrical Characteristics from TJ = 25°C to TJ = –40°C to 125°CGo
  • Updated UVLO minimum for falling VIN to 3.4 from 3.5 Go
  • Updated enable threshold rising maximum to 1.3 and falling minimum to 1.0, from 1.26 and 1.10, respectivelyGo

Changes from A Revision (December 2013) to B Revision

  • Changed ILIMIT2 test conditionsGo
  • Changed Functional Block DiagramGo
  • Changed Current Sharing Operation sectionGo
  • Changed Loop Compensation sectionGo

5 Description (continued)

Low-side reverse overcurrent protection also prevents excessive sinking current from damaging the converter. TPS65279 also features a light load pulse skipping mode (PSM) controlled by MODE pin configuration.

The TPS65279 is available in a 32-pin thermally-enhanced HTSSOP (DAP) package and 36-pin 6-mm × 6-mm VQFN (RHH) package.

6 Pin Configuration and Functions

DAP Package
32-Pin HTSSOP
Top View
TPS65279 po_dap_slvsc83.gif
RHH Package
36-Pin VQFN
Top View
TPS65279 po_rhh_slvsc83.gif

Pin Functions

PIN DESCRIPTION
NAME HTSSOP VQFN
EN1, EN2 1, 2 32, 33 Enable pin. Adjust the input under-voltage lockout with two resistors.
PGND2 3, 4 34, 35, 36 Power ground of buck2, place the input capacitor’s ground pin as close as possible to this pin.
PVIN2 5, 6 1, 2 Power input. Input power supply to the power switches of the power converter 2.
ISHARE 7 3 Logic pin to configure current sharing mode, tie to high to parallel two buck converters, in current sharing mode, buck1 will be used; tie to low to run in separate mode.
MODE 8 4 Connecting this pin to ground, the buck converter forces a continuous current mode (CCM) operation. Connecting this pin to V7V, the buck converter automatically operates in pulse skipping mode (PSM) at light load condition to save the power.
V7V 9 5 Internal low-drop linear regulator (LDO) output to power internal driver and control circuits. Decouple this pin to power ground with a minimum
1-µF ceramic capacitor. Output regulates to typical 6.3 V for optimal conduction on-resistances of internal power MOSFETs. In PCB design, the power ground and analog ground should have one-point common connection at the (-) terminal of V7V bypass capacitor. If VIN is lower than 6.3 V, V7V will be slightly lower than VIN.
VIN 10 6 Power supply of the internal LDO and controllers
PVIN1 11, 12 7, 8 Power input. Input power supply to the power switches of the power converter 1.
PGND1 13, 14 9, 10, 11 Power ground of buck1, place the input capacitor’s ground pin as close as possible to this pin.
PGOOD1 15 12 Power Good pin for buck1, open drain output, when output is within range, output high impedance, a 100-kΩ resistor is recommended to connect to this pin.
PGOOD2 16 13 Power Good pin for buck2, open drain output, when output is within range, output high impedance, a 100-kΩ resistor is recommended to connect to this pin.
FB1 17 14 Feedback sensing pin for buck1 output voltage. Connect this pin to the resistor divider of buck1 output. The feedback reference voltage is 0.6 V ±1%.
RLIM1 18 15 Current limit threshold set pin for buck1, connect a resistor between this pin to GND to set the OCP.
BST1 19 16 Add a bootstrap capacitor between BST1 and LX1. The voltage on this capacitor carries the gate drive voltage for the high-side MOSFET.
LX1 20, 21 17, 18, 19 Switching node of buck1
SS1 22, 27 20, 25 Soft-start and voltage tracking in buck1. An external capacitor connected to this pin sets the internal voltage reference rise time. Since the voltage on this pin overrides the internal reference, it can be used for tracking and sequencing. In current sharing application, this pin serves as the soft-start pin.
COMP1 23 21 Error amplifier output and loop compensation pin for buck1. Connect frequency compensation to this pin; In current sharing application, this pin serves as the compensation pin.
ROSC 24 22 Oscillator frequency programmable pin. Connect an external resistor to set the switching frequency. When connected to an external clock, the internal oscillator synchronizes to the external clock.
AGND 25 23 Analog ground of the controllers
COMP2 26 24 Error amplifier output and loop compensation pin for buck2. Connect frequency compensation to this pin. In current sharing application, float this pin.
SS2 27 25 Soft-start and voltage tracking in buck2. An external capacitor connected to this pin sets the internal voltage reference rise time. Since the voltage on this pin overrides the internal reference, it can be used for tracking and power sequencing. In current sharing application, float this pin.
LX2 28, 29 26, 27, 28 Switching nodes
BST2 30 29 Add a bootstrap capacitor between BST2 and LX2. The voltage on this capacitor carries the gate drive voltage for the high-side MOSFET of
buck2.
RLIM2 31 30 Current limit threshold set pin for buck2, connect a resistor between this pin to GND to set the OCP.
FB2 32 31 Feedback sensing pin for buck2 output voltage. Connect this pin to the resistor divider of buck2 output. The feedback reference voltage is 0.6 V ±1%. In current sharing mode, connect this pin to ground.
Exposed Thermal Pad 33 37 Exposed thermal pad of the package. Connect to the power ground. Always solder thermal pad to the board, and have as many vias as possible on the PCB to enhance power dissipation. There is no electric signal down bonded to the thermal pad inside the IC package.

 
Texas Instruments

© Copyright 1995-2025 Texas Instruments Incorporated. All rights reserved.
Submit documentation feedback | IMPORTANT NOTICE | Trademarks | Privacy policy | Cookie policy | Terms of use | Terms of sale