High-Voltage Step-Up LED Driver
Description
MCP1662
High-Voltage Step-Up LED Driver with UVLO and Open Load Protection
Features
• 36V, 800 m Integrated Switch • Up to 92% Efficiency • Drive LED Strings in Constant Current • 1.
3A Peak Input Current Limit:
- ILED up to 200 mA @ 5.
0V VIN, 4 White LEDs - ILED up to 125 mA @ 3.
3V VIN, 4 White LEDs - ILED up to 100 mA @ 4.
2V VIN, 8 White LEDs • Input Voltage Range: 2.
4V to 5.
5V • Feedback Voltage Reference: VFB = 300 mV • Undervoltage Lockout (UVLO): - UVLO @ VIN Rising: 2.
3V, typical - UVLO @ VIN Falling: 1.
85V, typical • Sleep Mode with 20 nA Typical Quiescent Current • PWM Operation: 500 kHz Switching Frequency • Cycle-by-Cycle Current Limiting • Internal Compensation • Open Load Protection (OLP) in the Event of: - Feedback pin shorted to GND (prevent
excessive current into LEDs) - Disconnected LED string (prevent overvoltage
to the converter’s Output and SW pin) • Overtemperature Protection • Available Packages:
- 5-Lead SOT-23 - 8-Lead 2x3 TDFN
Applications
• Two and Three-Cell Alkaline or NiMH/NiCd White LED Driver for Backlighting Products
• Li-Ion Battery LED Lighting Application • Camera Flash • LED Flashlights and Backlight Current Source • Medical Equipment • Portable Devices:
- Handheld Gaming Devices - GPS Navigation Systems - LCD Monitors - Portable DVD Players
General Description
The MCP1662 device is a compact, space-efficient, fixed-frequency, non-synchronous step-up converter optimized to drive LED strings with constant current from a two- or three-cell alkaline or lithium Energizer®, or NiMH/NiCd, or one-cell Lithium-Ion or Li-Polymer batteries.
The device integrates a 36V, 800 m low-side switch, which is protected by the 1.
3A cycle-by-cycle inductor peak current limit operation.
All compensation and protection circuitry is integrated to minimize the number of external components.
The internal feedback (VFB) voltage is set to 300 mV for low power dissipation when sensing and regulating the LED current.
A single resistor sets the LED current.
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