Microchip MCP1664

Description

The MCP1664 is a compact, space-efficient,fixed-frequency, non-synchronous step-up converteroptimized to drive multiple strings of LEDs withconstant current powered from two and three-cellalkaline or NiMH/NiCd as well as from one-cell Li-Ion orLi-Polymer batteries.The device integrates a 36V, 400 m low-side switch,which is protected by the 1.8A cycle-by-cycle inductorpeak current limit operation. The MCP1664 starts upwithout high inrush current or output overshoot. Allcompensation and protection circuitry is integrated tominimize the number of external components.The internal feedback (VFB) voltage is set to 300 mV forlow power dissipation when sensing and regulating theLED current. A single resistor sets the LED current.The device features an UVLO which avoids start-upwith low inputs or discharged batteries for twocell-powered applications.The MCP1664 features an open load protection (OLP)which turns off the operation in situations when theLED string is accidentally disconnected or the feedbackpin is short-circuited to GND.While in Shutdown mode (EN = GND), the device stopsswitching, and consumes 40 nA typical of input current.

Features

• 36V, 400m Integrated Switch
• Up to 92% Efficiency
• Drive LED Strings in Constant Current
• 1.8A Peak Input Current Limit:
• ILED up to 200 mA at 3.3V VIN, 4 White LEDs
• ILED up to 300 mA at 5.0V VIN, 4 White LEDs
• ILED up to 150 mA at 4.2V VIN, 8 White LEDs
• Input Voltage Range: 2.4V to 5.5V
• Undervoltage Lockout (UVLO):
• UVLOatVIN Rising: 2.3V, typical
• UVLOatVIN Falling: 1.85V, typical
• Shutdown Current (EN = GND): 40 nA Typical
• 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 (PreventExcessive Current into LEDs)
• Disconnected LED String (PreventOvervoltage to the Converter’s Output andSW Pin)
• Overtemperature Protection
• Available Packages:
• 5-Lead SOT-23
• 8-Lead 2x3 TDFN

Typical applications

• Camera Flash
• GPS Navigation Systems
• Medical Equipment
• LED Flashlights and Backlight Current Source
• Portable Devices:
• Li-Ion Battery LED Lightning Application
• Hand-Held Gaming Devices
• Two and Three-Cell Alkaline or NiMH/NiCd White LED Driver for Backlighting Products
• Portable DVD Players
• LCD Monitors

More information

• Datasheet
• IC product information