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IC-Hersteller Microchip

IC-Hersteller (79)

Microchip MCP1643 | Demoboard ADM00435

1 MHz Low Start-up Voltage Synchronous Boost LED Constant Current Regulator

Details

Topologie Sonstige Topologie
Schaltfrequenz 850-1150 kHz
IC-Revision A

Beschreibung

MCP1643 is a compact, high-efficiency, fixed frequency, synchronous step-up converter optimized to drive one LED with constant current, that operates from one and two-cell alkaline and NiMH/NiCd batteries.The device can also drive two red/green/yellow series connection LEDs.

Low-voltage technology allows the regulator to start up without high-output voltage and load-current overshoot from a low 0.65V input. High efficiency is accomplished by integrating the low resistance N-Channel Boost switch and synchronous P-Channel switch. All compensation and protection circuitry are integrated to minimize external components.

The internal feedback (VFB) voltage is set to 120 mV for low power Dissipation when sensing and regulating LED current. A single resistor sets the constant current output that drives the LED load.

The device features an output overvoltage protection That limits the output voltage to 5.0V typical, in case the LED fails or output load is disconnected.

The LED will either be turned OFF or turned ON using the enable input. A True Output Load Disconnect mode provides input-to-output isolation while Shutdown (EN = GND) by removing the normal boost regulatordiode path from input to output. Shutdown state consumes 1.2 μA from input at room temperature.

The LED can be turned on and off with a variable duty cycle pulse-width modulation (PWM) signal applied to the EN pin for dimming applications.

The device also features a thermal shutdown at +150°C, with +25°C hysteresis.

Two package options, MSOP-8 and 2x3 DFN-8, are available.

Eigenschaften

  • 1.6A Typical Peak Input Current Limit
  • Up to 550 mA LED Load Current
  • Low Start-up Voltage: 0.65V (typical, 25 mA LEDCurrent)
  • Low Operating Input Voltage: down to 0.5V
  • Maximum Input Voltage < VLED < 5.0V
  • Maximum Output Voltage:
  • 5.0V
  • Overvoltage Protection
  • Low Reference Voltage:
  • VFB = 120 mV
  • Minimal Power Loss on Sense Resistor
  • Pulse-Width Modulation Mode Operation (1 MHz)
  • Internal Synchronous Rectifier
  • Internal Compensation
  • Inrush Current Limiting
  • Internal Soft-Start (240 μs typical)
  • Shutdown (EN = GND):
  • True Load Disconnect
  • Dimming Control by Variable Duty Cycle
  • Shutdown Current: 1.2 μA (typical)
  • Overtemperature protection
  • Packages:
  • MSOP-8
  • 2x3 DFN-8

Typische Anwendungen

  • Wall LED Lamps with Motion Detectors
  • General LED constant current applications
  • One and Two Cell Alkaline and NiMH/NiCd Portable LED Lighting Products
  • Rechargeable Flashlights
  • LED Flashlight and Head Lamps
  • LED supply for backlights

Weiterführende Informationen

Artikeldaten

Artikel Nr. Daten­blatt Downloads Produktserie L
(µH)
IR
(A)
ISAT
(A)
RDC typ.
(mΩ)
fres
(MHz)
Montageart Poles Muster
744025004
STE ALT EAG CAD LTS PSP SPE IGS CAD WE-TPC SMT-Speicherdrossel 4.7 1.35 1.7 100 84 SMT
418121270801
STE 3D ALT EAG IGS CAD WS-DISV Small Compact SMT with Raised Actuator 2.54 mm 0.025 1
416131160802
IGE STE 3D ALT EAG CAD WS-DISV Small Compact SMT Flat Actuator with Top Tape 1.27 mm 2
Artikel Nr. Daten­blatt
744025004
418121270801
416131160802
Muster
Artikel Nr. Daten­blatt Downloads Produktserie L
(µH)
IR
(A)
ISAT
(A)
RDC typ.
(mΩ)
fres
(MHz)
Montageart Poles Muster