LM5155 Non-Synchronous Boost Controller

By Texas Instruments 65

LM5155 Non-Synchronous Boost Controller

Texas Instruments' LM5155 device is a wide input range, non-synchronous boost controller that uses peak current mode control and can be used in boost, SEPIC, and flyback topologies.

The LM5155 device 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 internal VCC regulator also supports BIAS pin operation up to 45 V (50 V absolute maximum). The switching frequency is dynamically programmable with an external resistor from 100 kHz to 2.2 MHz. Switching at 2.2 MHz minimizes AM band interference and allows for a small solution size and fast transient response.

The device features a 1.5 A standard MOSFET driver and a low 100 mV current limit threshold. The device supports the use of an external VCC supply to improve efficiency. Low operating current and pulse-skipping operation improve efficiency at light loads.

The device has built-in protection features such as cycle-by-cycle current limit, overvoltage protection, line UVLO, and thermal shutdown. Hiccup-mode overload protection is available in the LM51551 device option. The controller includes low shutdown IQ, programmable soft-start, programmable slope compensation, precision reference, a PGOOD indicator, and external clock synchronization.

  • Wide input operating range for battery applications
    • Operating range: 3.5 V to 45 V
    • 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 (IQ ≤ 2.6 µA)
    • Low operating current (IQ ≤ 480 µA)
  • Small solution size and low-cost:
    • Maximum switching frequency: 2.2 MHz
    • 12-pin WSON package: 3 mm x 2 mm
    • Integrated error amp allows primary-side regulation without optocoupler (flyback)
    • Minimized undershoot during cranking (start-stop application)
  • Accurate ±1% accuracy feedback reference
  • Programmable extra slope compensation
  • High 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: 100 kHz to 2.2 MHz
  • Integrated protection:
    • Constant peak current limiting over input voltage
    • Optional hiccup-mode short-circuit protection
    • Programmable line UVLO
    • OVP protection
    • Thermal shutdown
  • Adjustable soft-start
  • PGOOD indicator
  • Multiple output flybacks without optocouplers
  • LED bias supplies
  • Wide input boosts, SEPICs, and flyback power modules
  • Portable speakers
  • Battery-powered boosts, SEPICs, and flybacks

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