MP1529 2.7-5.5V, 1.2MHz Fixed Frequency Step-Up Converter LCD Backlight Plus Flash QFN16

MP1529 2.7-5.5V, 1.2MHz Fixed Frequency Step-Up Converter LCD Backlight Plus Flash QFN16

The MP1529 is a step-up converter for driving two 6-LED backlight strings to 30mA and a 4-LED flash string to 150mA from a single Lithium-Ion battery.

Key Specifications

Features

• 2.7V to 5.5V Input Voltage Range
• 25V Maximum Step-Up Voltage
• <1µA Shutdown Mode
• 1.2MHz Fixed Frequency Operation
• LCD Backlight to 30mA, Flash to 150mA
• Cycle-By-Cycle Current Limit
• Independent Backlight, Preview and Flash Current Adjustment
• Special PWM Dimming
• Over Voltage Protection
• Under Voltage Lockout

Typical Application Circuit

Applications

• Cellular Phones
• Digital Still Cameras
• Digital Video Cameras "MPS" and "The Future of Analog IC Technology" are Registered Trademarks of Monolithic Power Systems, Inc.

Design Notes

• Size the inductor for the ripple current at the actual switching frequency, typically 30% of the DC load — not for the DC rating alone.
• The hot loop from input capacitor through the switch to ground sets conducted EMI. Keep that copper area as small as the layout allows.
• Output ripple is set by the capacitor ESR and its DC-bias derating; a 10 µF ceramic often behaves like 4 µF at the rated output voltage.
• Route the feedback divider from the output capacitor terminals, away from the switch node.

Common Questions