Diodes Incorporated
Back to Medium and Low Voltage DC-DC LED Drivers


Contact Sales

Log in or register to manage email notifications about changes to datasheets or PCNs for this part.


The ZXLD1321 is an inductive DC-DC converter, with an internal switch, designed for driving single or multiple 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 current limiting and supports step-up (Boost) mode and self-powering Bootstrap operating modes, 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, high power 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 the ZXLD1321 provides excellent load and current regulation, resulting in very stable LED current over the useful life of the battery and over the full operating 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 to the ADJ pin. An on-chip LED protection circuit also allows output current to be reduced linearly above a predetermined threshold temperature using an external thermistor 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.


  • 1.2V to 12V Input voltage range
  • Up to 1A output current
  • Typical efficiency >85%
  • Bootstrap operation enables input voltage down to 1V
  • User-defined thermal control of LED output current using external thermistor
  • High output current stability over input voltage and temperature
  • 12μA typical standby current
  • LED current adjustable from 100% down to 2%
  • Adjustable soft-start
  • Drives up to 5 white LEDs in series


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

Product Specifications

Product Parameters

AEC Qualified No
Compliance (Only Automotive supports PPAP) Standard
Topologies (Buck) No
Topologies (Buck-Boost) No
Topologies (Boost) Yes
Topologies (Charge Pump) No
Minimum Input Voltage (V) 1.2
Maximum Input Voltage (V) 12
Maximum Output Voltage (V) 18
Maximum LED Current (A) 1
Switching Frequency Maximum (kHz) 600
Dimming (PWM) Yes
Dimming (Analog) Yes
Efficiency (%) 85
Operating Temperature Range (°C) -40 to 125
Quiescent Current Typ (mA) 1.5
AEC-Q100 Grade No

Related Content


Technical Documents

ICP Reports

Design tool model software

Reliability Reports

Evaluation Boards and User Guides

Recommended Soldering Techniques