Monolithic High-Efficiency LED Drivers

By STMicroelectronics 44

Monolithic High-Efficiency LED Drivers

STMicroelectronics' LED6001 device is an LED driver that combines a boost controller and a high-side current-sensing circuitry optimized for driving one string of high-brightness LEDs. The device is compatible with multiple topologies such as boost, SEPIC and floating load buck-boost. The brightness of the LEDs can be controlled through PWM dimming and analog dimming (10:1 ratio) by means of two independent pins. Enhanced PWM dimming can be obtained thanks to a MOSFET in series with the LED string and directly driven by a dedicated pin.

The LED2000/2001 is an 850 kHz fixed switching frequency monolithic step-down DC-DC converter designed to operate as precise constant current source with an adjustable current capability up to 3 A and 4 A DC. The embedded PWM dimming circuitry features LED brightness control. The regulated output current is set connecting a sensing resistor to the feedback pin. The embedded synchronous rectification and the 100 mV typical RSENSE voltage drop enhance the efficiency performance. The size of the overall application is minimized thanks to the high switching frequency and ceramic output capacitor compatibility. The device is fully protected against thermal overheating, overcurrent and output short-circuit. The LED2000/2001 is available in VFQFPN 4 mm x 4 mm 8-lead, and standard SO8 package.

The LED5000 is an 850 kHz fixed switching frequency monolithic step-down DC-DC converter designed to operate as a precise constant current source with an adjustable current capability up to 3 A DC. The embedded PWM dimming circuitry features LED brightness control. The regulated output current level is set by connecting a sensing resistor to the feedback pin. The 200 mV typical RSENSE voltage drop enhances performance in terms of efficiency. The size of the overall application is minimized thanks to the high switching frequency and its compatibility with ceramic output capacitors. The device is fully protected against overheating, overcurrent and output short-circuit. The LED5000 is available in an HSOP8 package.

LED6001 Features
  • 5.5 V to 36 V input voltage range
  • Very-low shutdown current: ISHDN< 10 μA
  • Internal +5 V LDO for gate driver supply
  • Internal +3.3 V LDO for device supply
  • Fixed-frequency peak current mode control
  • Adjustable (100 kHz to 1 MHz) switching frequency
  • External synchronization for multi-device applications
  • High-performance external MOSFET driver
  • Cycle-by-cycle external MOSFET OCP
  • Fixed internal soft-start
  • Programmable output OVP
  • Boost, buck-boost and SEPIC topologies supported
LED2000/2001 Features
  • 3.0 V to 18 V operating input voltage range
  • 850 kHz fixed switching frequency
  • 100 mV typ. current-sense voltage drop
  • PWM dimming
  • ± 7% output current accuracy
  • Synchronous rectification
  • 95 mΩ HS / 69 mΩ LS typical RDS(on)
  • Peak current mode architecture
  • Embedded compensation network
  • Internal current limiting
  • Ceramic output capacitor compliant
  • Thermal shutdown
LED5000 Features
  • 5.5 V to 48 V operating input voltage range
  • 850 kHz fixed switching frequency
  • 200 mV typ. current-sense voltage drop
  • Buck / buck-boost / floating-boost topologies
  • PWM dimming
  • ±3% output current accuracy over temperature
  • 200 mW typical RDS(on)
  • Peak current mode architecture
  • Short-circuit protection
  • Compliant with ceramic output capacitors
  • Inhibit for zero current consumption
  • Thermal shutdown

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