Diodes Incorporated ZXLD1320 | Demoboard ZXLD1320EV1

Description

The ZXLD1320 is an inductive DC-DC converter, with an internal switch, designed for driving single or multiple LEDs in series up to a total of 1.5A outputcurrent.Applications cover both commercial andautomotive environments with input voltages ranging from 4V to 18V. Depending upon supply voltage andexternal components, this can provide up to 24W of output power.The device employs a variable ‘on’ and ‘off’ time control scheme with adjustable peak switch current limiting and operates in the step-down (Buck) operating mode, offering higher power 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 features.The feedback control circuitry inside theZXLD1320 provides excellent load and current regulation, resulting in very stable LED current over the full operating voltage and temperature 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.An on-chip LED protection circuit also allows output current to be reduced linearly above a predeterminedthreshold temperature using an external thermistor at the TADJ pin.External resistors set nominal average LED current and coil peak current independently.The ‘Power-OK’ (POK) output flag remains high during normal operation, but switches low if the switch transistor remains on for more than 500us. Thisprovides indication of a low battery, or fault condition.The POK output may be used to drive an LED or the input of an MCU.The device can be shut down by applying a continuous low level dc voltage to the ADJ pin.

Features

• Step Down LED Driver
• 4V to 18V Input Voltage Range
• Up to 1.5A output current
• Typical efficiency *> 85%
• User-defined thermal control of LED output currentusing external thermistor
• 12μA typical standby current
• Adjustable Soft-Start
• Power ‘OK’ flag output
• Capable of driving 4 LEDs in series

Typical applications

• General LED lighting
• LED back-up lighting
• Automotive Lighting
• Low voltage halogen lamp replacement with LEDs
• High Power LED flashlights

More information

• Datasheet
• IC product information