- Dual high-side current sources
- Cathode grounding allows for better heat dissipation and LED routing
- > 90% efficiency
- 超小型解决方案尺寸： 2
- Four working modes: torch, flash, LED indicator and voltage output
- Accurate and programmable LED current from 1.2A to 37.5 mA
- Programmable 4.5V or 5.0V fixed output voltage
- Hardware flash and flashlight enabled
- LED thermal induction and current scaleback
- Software-selectable input voltage monitor
- Programmable Flash timeout
- RF power amplifier dual synchronous input pulse events
- LED open circuit and short circuit detection
- High level enables system hardware fault protection
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400kHz me 2 C compatible interface
- 16 bumps (1.7 mm× 1.7 mm×0.6 mm) micro SMD
illustrate
The LM3554 is a 2MHz fixed-frequency, current-mode synchronous boost converter. The device is designed to work as two 600mA (1.2A total) constant current high-current white LED drivers, or as a regulated 4.5V or 5V voltage source.
Dual high-side current sources allow LED cathode grounding operation. An adaptive regulation approach that ensures efficiency is maintained and maximized at each LED current source regulated.
Its main functions include: an I 2 C-compatible interface for controlling LED current or desired output voltage, hardware flash enables direct flash pulse trigger input, dual TX input, forced into low-current torch synchronization mode allows for flash pulse RF power amplifier events or other high-current conditions. In addition, the aggressive high hardware enable (HWEN) input provides hardware shutdown in the event of a system software failure.
Five protection features include a software-selectable input voltage monitor, an interface with external temperature sensor, four selectable current limits to ensure battery current is constantly below predetermined peaks, an overvoltage protection function, an internal comparator limits the output voltage on the LED open circuit and output short-circuit protection to limit the output current when shorting to GND. In addition, the device provides indicators of various faults, including: a thermal fault flag indicating that the LED temperature has tripped over, a flag indicating that the TX event has occurred, a flag indicating that the flash timeout counter has expired, a flag indicating that the device chip temperature has reached the thermal shutdown threshold, and an open flag indicating or short-circuiting the LED.
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