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LM51551

ACTIVE

2.2-MHz wide VIN nonsynchronous boost, flyback, & SEPIC controller with hiccup

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Data sheet

LM51551

ACTIVE
Data sheet Order now

Product details

Rating Catalog Topology Boost, Flyback, SEPIC Vin (max) (V) 45 Vin (min) (V) 1.5 Vout (max) (V) 300 Vout (min) (V) 1.5 Features Adjustable current limit, Frequency synchronization, Hiccup mode protection, Nonsynchronous rectification, Power good, UVLO adjustable Duty cycle (max) (%) 93 Iq (typ) (A) 0.00045 TI functional safety category Functional Safety-Capable Operating temperature range (°C) -40 to 125
Rating Catalog Topology Boost, Flyback, SEPIC Vin (max) (V) 45 Vin (min) (V) 1.5 Vout (max) (V) 300 Vout (min) (V) 1.5 Features Adjustable current limit, Frequency synchronization, Hiccup mode protection, Nonsynchronous rectification, Power good, UVLO adjustable Duty cycle (max) (%) 93 Iq (typ) (A) 0.00045 TI functional safety category Functional Safety-Capable Operating temperature range (°C) -40 to 125
WSON (DSS) 12 6 mm² (3 mm × 2 mm)
  • Functional Safety-Capable
    • Documentation available to aid functional safety system design
  • Wide input operating range for battery applications
    • 3.5-V to 45-V operating range
    • 2.97-V to 16-V when BIAS = VCC
    • Minimum boost supply voltage 1.5 V when BIAS ≥ 3.5 V
    • Input transient protection up to 50 V
  • Minimized battery drain
    • Low shutdown current (I Q ≤ 2.6 µA)
    • Low operating current (I Q ≤ 480 µA)
  • Small solution size and low cost
    • Maximum switching frequency of 2.2 MHz
    • 12-Pin WSON package (3 mm × 2 mm)
    • Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
    • Minimized undershoot during cranking (start-stop application)
  • Higher efficiency with low-power dissipation
    • 100-mV ±7% Low current limit threshold
    • Strong 1.5-A peak standard MOSFET driver
    • Supports external VCC supply
  • Avoid AM band interference and crosstalk
    • Optional clock synchronization
    • Dynamically programmable switching frequency from 100 kHz to 2.2 MHz
  • Integrated protection features
    • Constant peak current limiting over input voltage
    • Optional hiccup mode short-circuit protection (see the Device Comparison Table)
    • Programmable line UVLO
    • OVP protection
    • Thermal shutdown
  • Accurate ±1% accuracy feedback reference
  • Programmable extra slope compensation
  • Adjustable soft start
  • PGOOD indicator
  • Create a custom design using the LM5155x with the WEBENCH power designer
  • Functional Safety-Capable
    • Documentation available to aid functional safety system design
  • Wide input operating range for battery applications
    • 3.5-V to 45-V operating range
    • 2.97-V to 16-V when BIAS = VCC
    • Minimum boost supply voltage 1.5 V when BIAS ≥ 3.5 V
    • Input transient protection up to 50 V
  • Minimized battery drain
    • Low shutdown current (I Q ≤ 2.6 µA)
    • Low operating current (I Q ≤ 480 µA)
  • Small solution size and low cost
    • Maximum switching frequency of 2.2 MHz
    • 12-Pin WSON package (3 mm × 2 mm)
    • Integrated error amplifier allows primary-side regulation without optocoupler (flyback)
    • Minimized undershoot during cranking (start-stop application)
  • Higher efficiency with low-power dissipation
    • 100-mV ±7% Low current limit threshold
    • Strong 1.5-A peak standard MOSFET driver
    • Supports external VCC supply
  • Avoid AM band interference and crosstalk
    • Optional clock synchronization
    • Dynamically programmable switching frequency from 100 kHz to 2.2 MHz
  • Integrated protection features
    • Constant peak current limiting over input voltage
    • Optional hiccup mode short-circuit protection (see the Device Comparison Table)
    • Programmable line UVLO
    • OVP protection
    • Thermal shutdown
  • Accurate ±1% accuracy feedback reference
  • Programmable extra slope compensation
  • Adjustable soft start
  • PGOOD indicator
  • Create a custom design using the LM5155x with the WEBENCH power designer

The LM5155x (LM5155 and LM51551) is a wide input range, non-synchronous boost controller that uses peak current mode control. The device can be used in boost, SEPIC, and flyback topologies.

The LM5155x can start up from a 1-cell battery with a minimum of 2.97 V if the BIAS pin is connected to the VCC pin. It can operate with the input supply voltage as low as 1.5 V if the BIAS pin is greater than 3.5 V.

The LM5155x (LM5155 and LM51551) is a wide input range, non-synchronous boost controller that uses peak current mode control. The device can be used in boost, SEPIC, and flyback topologies.

The LM5155x can start up from a 1-cell battery with a minimum of 2.97 V if the BIAS pin is connected to the VCC pin. It can operate with the input supply voltage as low as 1.5 V if the BIAS pin is greater than 3.5 V.
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Technical documentation

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Top documentation Type Title Format options Date
* Data sheet LM5155x 2.2-MHz Wide Input Nonsynchronous Boost, SEPIC, Flyback Controller datasheet (Rev. E) PDF | HTML May 9, 2023
Technical article Isolating a SEPIC PDF | HTML Feb 26, 2024
Technical article Designing a CCM flyback converter PDF | HTML Feb 23, 2024
Technical article Designing a DCM flyback converter PDF | HTML Feb 23, 2024
Technical article Flyback converter design considerations PDF | HTML Feb 21, 2024
Technical article Get more boost from your boost converter PDF | HTML Dec 21, 2023
Application note How to Implement the Soft Start in a Flyback PDF | HTML Jul 10, 2023
Application note Programmable ±HV Power Supply With Low Static Power Consumption for Smart Probe PDF | HTML Sep 19, 2022
Application note How to Design an Isolated Flyback Using LM5155 (Rev. A) PDF | HTML Jan 5, 2021
Functional safety information LM5155x FIT Rate and Failure Mode Distribution Feb 4, 2020
Application note How to Design a Boost Converter Using LM5155 Dec 17, 2018

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM5155EVM-BST — LM5155 Boost Controller Evaluation Module

The LM5155EVM-BST evaluation module showcases the features and performance of the LM5155, wide input non-synchronous boost controller. The standard configuration is designed to provide a regulate output of 24V at 2A from an input of 6V to 18V, switching at 440 kHz.

This EVM is designed for ease of (...)

User guide: PDF
Supported products & hardware
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Evaluation board

LM5155EVM-FLY — LM5155 Flyback Controller Evaluation Module

The LM5155EVM-FLY evaluation module showcases the features and performance of the LM5155 as a wide input non-synchronous flyback controller. The standard configuration is designed to provide a regulated output of 5V at 4A from an input of 18V to 36V, switching at 250 kHz. This evaluation module is (...)
User guide: PDF | HTML
Supported products & hardware
In stock
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Evaluation board

LM5155EVM-SEPIC — LM5155 SEPIC evaluation module

The LM5155EVM-SEPIC evaluation module showcases the features and performance of the LM5155 as wide input non-synchronous SEPIC controller. The standard configuration is designed to provide a regulated output of 12V at up to 2A from an input of 3V to 42V, switching at 2.2 MHz.
User guide: PDF | HTML
Supported products & hardware
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Simulation model

LM5155-Q1 PSpice Transient Model (unencrypted) (Rev. H)

SNVMBL2H.ZIP (206 KB) - PSpice model
Supported products & hardware
Simulation model

LM5155-Q1 TINA-TI STARTUP REFERENCE DESIGN

SNVMBV8.TSC (1162 KB) - TINA-TI reference design
Supported products & hardware
Simulation model

LM5155-Q1 TINA-TI TRANSIENT SPICE MODEL

SNVMBV7.ZIP (52 KB) - TINA-TI Spice model
Supported products & hardware
Simulation model

Unencrypted LM5155-Q1 PSpice Average Model (Rev. B)

SNVMBY3B.ZIP (81 KB) - PSpice model
Supported products & hardware
Calculation tool

SNVC224 — LM5155/56 Boost Controller Quick Start Calculator

Supported products & hardware
Calculation tool

SNVC240 — LM5155/56 Flyback Controller Quick Start Calculator

LM5155/56 Flyback Controller Quick Start Calculator
Supported products & hardware
Calculation tool

SNVR481 — LM5155/56 SEPIC Controller Quick Start Calculator

Supported products & hardware
Reference design

PMP22764 — Isolated flyback converter (24-V to 56-V/1.25-A) reference design

This reference design utilizes a diode rectified flyback converter for a 24-V input to isolated 56-V/1.25-A output. The LM51551 PWM controller provides the control for the flyback converter, including hiccup mode short circuit protection. This reference design is ideal for when any well-regulated (...)
Supported products & hardware
Reference design

PMP22800 — 24V, 1.2A DC/DC flyback reference design

This reference design uses the LM51551 as a secondary side regulated (SSR) flyback controller. It converts an input of 8 to 28.8 V and 24 V at a maximum power of 28.8 W. The supply starts up at a minimum input of 15.5 V and can operate to 8-V input. The design also includes the synchronous buck (...)
Supported products & hardware
Reference design

PMP30805 — Tiny automotive SEPIC reference design

This tiny automotive SEPIC reference design contains a 6-W auxiliary power supply and is designed for a 12-V bias rail. The wide input accepts cranking down to 4.5 Vmin and surge up to 40 Vmax. Due to switching frequency of 2 MHz, the dual inductor is fairly small, resulting in excellent dynamic (...)
Supported products & hardware
Package Pins CAD symbols, footprints & 3D models
WSON (DSS) 12 Ultra Librarian
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