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  • LM516x 具有 Fly-Buck 转换器功能的 0.65A/0.3A、120V 绝对最大值降压转换器

    • ZHCSPF2B December   2021  – December 2024 LM5168 , LM5169

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  • LM516x 具有 Fly-Buck 转换器功能的 0.65A/0.3A、120V 绝对最大值降压转换器
  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Control Architecture
      2. 7.3.2  Internal VCC Regulator and Bootstrap Capacitor
      3. 7.3.3  Internal Soft Start
      4. 7.3.4  On-Time Generator
      5. 7.3.5  Current Limit
      6. 7.3.6  N-Channel Buck Switch and Driver
      7. 7.3.7  Synchronous Rectifier
      8. 7.3.8  Enable, Undervoltage Lockout (EN/UVLO)
      9. 7.3.9  Power Good (PGOOD)
      10. 7.3.10 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 Sleep Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Fly-Buck™ Converter Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Switching Frequency (RT)
        2. 8.2.2.2  Transformer Selection
        3. 8.2.2.3  Output Capacitor Selection
        4. 8.2.2.4  Secondary Output Diode
        5. 8.2.2.5  Setting Output Voltage
        6. 8.2.2.6  Input Capacitor
        7. 8.2.2.7  Type-3 Ripple Network
        8. 8.2.2.8  CBST Selection
        9. 8.2.2.9  Minimum Secondary Output Load
        10. 8.2.2.10 Example Design Summary
      3. 8.2.3 Application Curves
    3. 8.3 Typical Buck Application
      1. 8.3.1 Design Requirements
      2. 8.3.2 Detailed Design Procedure
        1. 8.3.2.1 Switching Frequency (RT)
        2. 8.3.2.2 Buck Inductor Selection
        3. 8.3.2.3 Setting the Output Voltage
        4. 8.3.2.4 Type-3 Ripple Network
        5. 8.3.2.5 Output Capacitor Selection
        6. 8.3.2.6 Input Capacitor Considerations
        7. 8.3.2.7 CBST Selection
        8. 8.3.2.8 Example Design Summary
      3. 8.3.3 Application Curves
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Thermal Considerations
      2. 8.5.2 Typical EMI Results
      3. 8.5.3 Layout Guidelines
        1. 8.5.3.1 Compact PCB Layout for EMI Reduction
        2. 8.5.3.2 Feedback Resistors
      4. 8.5.4 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 第三方产品免责声明
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 接收文档更新通知
    4. 9.4 支持资源
    5. 9.5 Trademarks
    6. 9.6 静电放电警告
    7. 9.7 术语表
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
  13. 重要声明

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LM516x 具有 Fly-Buck 转换器功能的 0.65A/0.3A、120V 绝对最大值降压转换器

本资源的原文使用英文撰写。 为方便起见，TI 提供了译文；由于翻译过程中可能使用了自动化工具，TI 不保证译文的准确性。 为确认准确性，请务必访问 ti.com 参考最新的英文版本（控制文档）。

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1 特性

  • 功能安全型
    • 可提供用于功能安全系统设计的文档
  • 专为在严苛的应用中实现可靠性而设计
    • 6V 至 120V 的宽输入电压范围（绝对最大值）
    • 结温范围：-40°C 至 +150°C
    • 固定 3ms 内部软启动计时器
    • 峰值和谷值电流限制保护
    • 输入 UVLO 和热关断保护
  • 适用于可扩展的工业电源和电池包
    • 最短导通时间和关闭时间低至 50ns
    • 高达 1MHz 的可调节开关频率
    • 可实现高轻负载效率的二极管仿真
    • 自动模式下具有低静态电流 (< 10µA)
    • FPWM 模式支持 Fly-Buck 转换器功能
    • 3µA 关断静态电流
    • 与 LM5164-Q1、LM5163-Q1 和 LM5013-Q1 引脚对引脚兼容
    • 与 LM5017 和 LM34927 具有类似的引脚排列和功能。
  • 通过集成技术减小设计尺寸，降低成本
    • COT 模式控制架构
    • 集成式 1.9Ω NFET 降压开关
    • 集成 0.71Ω NFET 同步整流器
    • 1.2V 内部电压基准
    • 无环路补偿组件
    • 内部 VCC 偏置稳压器和自举二极管
    • 开漏电源正常状态指示器
    • 封装选项：SOIC PowerPAD™-8 集成电路封装或 WSON-8 封装

2 应用

  • 通信 – 砖型电源模块
  • 工业电池组（≥ 10 节）
  • 电池包 – 电动自行车、电动踏板车、LEV

3 说明

LM5169 和 LM5168 同步降压转换器用于在宽输入电压范围内进行调节，从而更大限度地减少对外部浪涌抑制元件的需求。50ns 的最短可控导通时间有助于实现较大的降压比，支持从 48V 标称输入到低电压轨的直接降压转换，从而降低系统的复杂性并减少解决方案成本。LM516x 在输入电压突降至 6V 时能够根据需要以接近 100% 的占空比工作，因而是宽输入电源电压范围工业应用和高电芯数电池包应用的理想之选。

凭借集成式高侧和低侧功率 MOSFET，LM5169 可提供高达 0.65A 的输出电流，LM5168 可提供高达 0.3A 的输出电流。恒定导通时间 (COT) 控制架构可提供几乎恒定的开关频率，具有出色的负载和线路瞬态响应。LM516x 能够以 FPWM 或自动模式运行。FPWM 模式在整个负载范围内实现强制 CCM 运行，支持隔离式 Fly-Buck 转换器应用。自动模式可实现超低 IQ 和二极管仿真模式运行，从而在轻负载下实现高效率。

器件信息
器件型号(3) 封装(1) 封装尺寸(2)
LM5169 DDA（HSOIC，8） 4.9mm × 6mm
NGU（WSON，8） 4.00mm × 4.00mm
LM5168 DDA（HSOIC，8） 4.9mm × 6mm
NGU（WSON，8） 4.00mm × 4.00mm
(1) 有关更多信息，请参阅节 11。
(2) 封装尺寸（长 × 宽）为标称值，并包括引脚（如适用）。
(3) 请参阅器件比较表。
LM5168 LM5169 典型降压应用电路典型降压应用电路
LM5168 LM5169 典型 Fly-Buck™ 转换器应用电路典型 Fly-Buck™ 转换器应用电路

4 Device Comparison Table

DEVICE NUMBER PACKAGE DESCRIPTION OUTPUT CURRENT LIGHT LOAD MODE CURRENT LIMIT
LM5168PDDAR DDA (HSOIC, 8) 0.3 A, buck, AUTO, no-hiccup 0.3 A PFM 0.42 A, no-hiccup
LM5168FDDAR 0.3 A, buck, FPWM, hiccup FPWM 0.42 A, hiccup
LM5169PDDAR 0.65 A, buck, AUTO, hiccup 0.65 A PFM 0.84 A, hiccup
LM5169FDDAR 0.65 A, buck, FPWM, hiccup FPWM 0.84 A, hiccup
LM5168PNGUR NGU (WSON, 8) 0.3 A, buck, AUTO, no-hiccup 0.3 A PFM 0.42 A, no-hiccup
LM5168FNGUR 0.3 A, buck, FPWM, hiccup FPWM 0.42 A, hiccup
LM5169PNGUR 0.65 A, buck, AUTO, hiccup 0.65 A PFM 0.84 A, hiccup
LM5169FNGUR 0.65 A, buck, FPWM, hiccup FPWM 0.84 A, hiccup

5 Pin Configuration and Functions

LM5168 LM5169 8-Pin SO PowerPAD™Integrated Circuit Package(Top View) Figure 5-1 8-Pin SO PowerPAD™Integrated Circuit Package(Top View)
LM5168 LM5169 8-Pin WSON NGU Package (Top View) Figure 5-2 8-Pin WSON NGU Package (Top View)
Table 5-1 Pin Functions
PIN TYPE(1) DESCRIPTION
NO. NAME
1 GND G Ground connection for internal circuits
2 VIN P/I Regulator supply input pin to the high-side power MOSFET and internal bias regulator. Connect directly to the input supply of the buck converter with short, low impedance paths.
3 EN/UVLO I Precision enable and undervoltage lockout (UVLO) programming pin. If the EN/UVLO rising voltage is below 1.1 V, the converter is in shutdown mode with all functions disabled. If the UVLO voltage is greater than 1.1 V and below 1.5 V, the converter is in standby mode with the internal VCC regulator operational and no switching. If the EN/UVLO voltage is above 1.5 V, the start-up sequence begins.
4 RT I On-time programming pin. A resistor between this pin and GND sets the buck switch on time.
5 FB I Feedback input of voltage regulation comparator
6 PGOOD O Power-good indicator. This pin is an open-drain output pin. Connect to a source voltage through an external pullup resistor between 10 kΩ to 100 kΩ. Connect to GND if the PGOOD feature is not needed.
7 BST P/I Bootstrap gate-drive supply. Required to connect a high-quality 2.2-nF X7R ceramic capacitor between BST and SW to bias the internal high-side gate driver.
8 SW P Switching node that is internally connected to the source of the high-side NMOS buck switch and the drain of the low-side NMOS synchronous rectifier. Connect to the switching node of the power inductor.
— EP — Exposed pad of the package. No internal electrical connection. Solder the EP to the GND pin and connect to a large copper plane to reduce thermal resistance.
(1) G = Ground, I = Input, O = Output, P = Power

6 Specifications

6.1 Absolute Maximum Ratings

Over operating junction temperature range (unless otherwise noted)(1) (2)
MIN MAX UNIT
Pin voltage VIN –0.3 120 V
SW –1.5 120
SW, transient < 20 ns –3
BST –0.3 125.5
BST – SW –0.3 5.5
EN –0.3 120
FB –0.3 5.5
RT –0.3 5.5
PGOOD –0.3 14
Bootstrap Capacitor(3) External BST to SW capacitance 2.5 nF
TJ Operating junction temperature –40 150 °C
Tstg Storage temperature –65 150 °C
(1) Operation outside the Absolute Maximum Ratings may cause permanent device damage. Absolute Maximum Ratings do not imply functional operation of the device at these or any other conditions beyond those listed under Recommended Operating Conditions. If used outside the Recommended Operating Conditions but within the Absolute Maximum Ratings, the device may not be fully functional, and this may affect device reliability, functionality, performance, and shorten the device lifetime.
(2) See the Applications section for PCB layout recommendations (Layout Guidelines).
(3) Specification applies to FPWM and Fly-Buck operation.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 V
Charged-device model (CDM), per ANSI/ESDA/JEDEC JS-002 (2) ±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

Over operating junction temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VIN Pin voltage VIN 6 115 V
VEN Pin voltage EN 115 V
IOUT Output current range LM5169 0.65 A
LM5168 0.3 A
CBST
External BST to SW capacitance

 FPWM Mode 2.2 nF
FSW Switching frequency 100 1000 kHz

6.4 Thermal Information

THERMAL METRIC(1) LM516x LM516x UNIT
DDA (SOIC) NGU (WSON)
8 PINS 8 PINS
RθJA(EVM) Junction-to-ambient thermal resistance for EVM(2) 22 15.8 °C/W
RθJA Junction-to-ambient thermal resistance 38.9 41.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 51.7 29.9 °C/W
ψJT Junction-to-top characterization parameter 2.9 0.3 °C/W
RθJB Junction-to-board thermal resistance 14.1 16.4 °C/W
ψJB Junction-to-board characterization parameter 14.1 16.4 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 3.3 4.3 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics
(2) This value is obtained on the LM5168PEVM and LM5169PEVM with approximately 49 cm2 of copper area.  See Thermal considerations section for more information.

6.5 Electrical Characteristics

TJ = –40°C to +150°C. Typical values are at TJ = 25°C and VIN = 24 V (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY
IQ(VIN) VIN quiescent current VEN = 2.5 V, PWM Operation 420 880 µA
VEN = 2.5 V, PFM Operation 10 25 µA
IQ(STANDBY) VIN standby current - LDO only VEN = 1.25 V 17 35 µA
ISD(VIN) VIN shutdown supply current VEN = 0 V, Tj=25°C 3 6 µA
ENABLE
VEN(R) EN voltage rising threshold EN rising, enable switching 1.45 1.5 1.55 V
VEN(F) EN voltage falling threshold EN falling, disable switching 1.35 1.4 1.44 V
VSD(R) EN standby rising threshold EN rising, enable internal LDO, no switching.  1.1 V
VSD(F) EN standby falling threshold EN falling, disable internal LDO. 0.45 V
REFERENCE VOLTAGE
VFB FB voltage VFB falling 1.181 1.2 1.218 V
STARTUP
tSS Internal fixed soft-start time 1.75 3 4.75 ms
POWER STAGE
RDSON(HS) High-side MOSFET on-resistance ISW = –100 mA 1.91 Ω
RDSON(LS) Low-side MOSFET on-resistance ISW = 100 mA 0.74 Ω
tON(min) Minimum ON pulse width 50 ns
tON(1) On-time1 VVIN = 6 V, RRT = 75 kΩ 5000 ns
tON(2) On-time2 VVIN = 6 V, RRT = 25 kΩ 1650 ns
tON(3) On-time3 VVIN = 12 V, RRT = 75 kΩ 2550 ns
tON(4) On-time4 VVIN = 12 V, RRT = 25 kΩ 830 ns
tOFF(min) Minimum OFF pulse width 50 ns
BOOT CIRCUIT
VBOOT-SW(UV_R) BOOT-SW UVLO rising threshold VBOOT-SW rising 2.6 3.4 V
OVERCURRENT PROTECTION
IHS_PK(OC) High-side peak current limit LM5168 0.356 0.42 0.484 A
LM5169 0.71 0.84 0.94 A
ILS_PK(OC) Low-side peak current limit LM5168 0.356 0.42 0.484 A
LM5169 0.71 0.84 0.94 A
IDELTA(OC) Min of IHS_PK(OC) or ILS_PK(OC)  minus ILS_V(OC) LM5168 0.084 A
LM5169  0.168 A
ILS(NOC) Low-side negative current limit LM5169 1.05 1.5 1.90 A
LM5168 0.4 0.75 1.1 A
ILS_V(OC) Low-side valley current limit LM5169 Low-side valley current limit on LS FET 0.569 0.672 0.775 A
LM5168 Low-side valley current limit on LS FET 0.27 0.336 0.42 A
IZC Zero-cross detection current threshold 0 A
TW Hiccup time before re-start 64 ms
POWER GOOD
VPGTH Power Good threshold FB falling, PG high to low 1.055 1.08 1.1 V
FB rising, PG low to high 1.105 1.14 1.175 V
RPG Power Good threshold VFB = 1 V 7 Ω
THERMAL SHUTDOWN
TJ(SD) Thermal shutdown threshold (1) Temperature rising 175 °C
TJ(HYS) Thermal shutdown hysteresis (1) 10 °C
(1) Specified by design, not product tested

6.6 Typical Characteristics

Unless otherwise specified the following conditions apply: At TA = 25°C, VIN = 24 V
LM5168 LM5169 Shutdown Supply Current Versus Input VoltageFigure 6-1 Shutdown Supply Current Versus Input Voltage
LM5168 LM5169 Active Mode Supply Current Versus Input Voltage (FPWM, non-switching)Figure 6-3 Active Mode Supply Current Versus Input Voltage (FPWM, non-switching)
LM5168 LM5169 Feedback Comparator Threshold Versus TemperatureFigure 6-5 Feedback Comparator Threshold Versus Temperature
LM5168 LM5169 Sleep Mode Supply Current Versus Input Voltage (DEM, non-switching)Figure 6-2 Sleep Mode Supply Current Versus Input Voltage (DEM, non-switching)
LM5168 LM5169 COT On Time Versus Input VoltageFigure 6-4 COT On Time Versus Input Voltage
LM5168 LM5169 MOSFETs On-State Resistance Versus TemperatureFigure 6-6 MOSFETs On-State Resistance Versus Temperature

7 Detailed Description

7.1 Overview

The LM5169 and LM5168 are easy-to-use, ultra-low IQ constant on-time (COT) synchronous step-down buck regulators. With integrated high-side and low-side power MOSFETs, the LM516x is a low-cost, highly efficient, buck converter that operates from a wide input voltage of 6 V to 120 V absolute maximum, delivering up to 0.65-A or 0.3-A DC load current. The LM516x is available in an 8-pin SO PowerPAD integrated circuit package with 1.27-mm pin pitch for adequate spacing in high-voltage applications. There is also a smaller 8-pin WSON package option available to help achieve a compact design. This constant on-time (COT) converter is an excellent choice for low-noise, high-current, and fast load transient requirements, operating with a predictive on-time switching pulse. Over the input voltage range, input voltage feed-forward is employed to achieve a quasi-fixed switching frequency. A controllable on time as low as 50 ns permits high step-down ratios and a minimum forced off time of 50 ns provides extremely high duty cycles. This feature enables fixed frequency operation as VIN drops close to VOUT. After the forced off time of 50 ns is reached, the device enters frequency fold-back operation to maintain a constant output voltage. The LM516x implements a smart peak and valley current limit detection circuit to make sure of robust protection during output short circuit conditions. Control loop compensation is not required for this regulator, reducing design time and external component count.

The LM5169 and LM5168 are pre-programmed to operate in auto mode or FPWM mode. When configured to operate in auto mode, at light loads, the device transitions into an ultra-low IQ mode to maintain high efficiency and prevent draining battery cells connected to the input when the system is in standby. When configured in FPWM mode, at light loads, the device maintains CCM operation, enabling Fly-Buck converter operation. The Fly-Buck converter configuration can be used to generate both a non-isolated primary output and an isolated secondary output.

The LM5169 and LM5168 incorporates additional features for comprehensive system requirements, including an open-drain power-good circuit for the following:

  • Power-rail sequencing and fault reporting
  • Internally fixed soft start
  • Monotonic start-up into prebiased loads
  • Precision enable for programmable line undervoltage lockout (UVLO)
  • Smart cycle-by-cycle current limit for optimal inductor sizing
  • Thermal shutdown with automatic recovery

The LM5169 and LM5168 support a wide range of end equipment requiring a regulated output from a high input supply where the transient voltage deviates from the DC level. Examples of such end equipment systems are the following:

  • 48-V automotive systems
  • High cell-count battery-pack systems
  • 24-V industrial systems
  • 48-V telecom and PoE voltage ranges

The pin arrangement is designed for a simple layout that requires only a few external components.

7.2 Functional Block Diagram

LM5168 LM5169

 
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