Diodes Incorporated ZXLD1321 | Demoboard ZXLD1321EV2

Description

The ZXLD1321 is an inductive DC-DC converter, with an internal switch, designed for driving single ormultiple LEDs in series up to a total of 1A output current.Applications cover commercial environments with input voltages ranging from 1.2V to 12V.The device employs a variable ‘on’ and ‘off’ time control scheme with adjustable peak switch currentlimiting and supports step-up (Boost) mode and selfpowering Bootstrap operating modes, offering higherpower efficiency and lower system cost than conventional PFM circuitry.The device includes the DC-DC converter, a high-side current monitor and an NPN switching transistor to provide an integrated solution offering small PCB size, competitive cost/performance, highpower efficiency of DC-DC conversion and maximum LED brightness/reliability. More importantly, it retains design flexibility to add customer specific featuresThe feedback control circuitry inside theZXLD1321 provides excellent load and current regulation, resulting in very stable LED current over the useful life of the battery and over the full operatingtemperature range.The LED current can be adjusted from 100% down to 10% of the set value by applying a dc voltage to the ADJ pin and down to 1% by applying a PWM signal tothe ADJ pin. An on-chip LED protection circuit also allows output current to be reduced linearly above a predetermined threshold temperature using an externalthermistor at the TADJ pin.External resistors set nominal average LED current and coil peak current independently.The device can be shut down by applying a continuous low level dc voltage to the ADJ pin.

Features

• 1.2V to 12V Input Voltage Range
• Up to 1A output current
• Typical efficiency (*) : >85%
• Bootstrap operation enables input voltage down to1V
• User-defined thermal control of LED output currentusing external thermistor
• 12μA typical standby current
• Adjustable Soft-Start
• Drives up to 5 white LEDs in series

Typical applications

• LED back-up lighting
• High power LED flashlights
• General LED lighting

More information

• Datasheet
• IC product information