Dear Sir/Madam,
I am currently using the LP8868-Q1 LED driver IC in a buck-boost topology to drive 5 LEDs under the following operating conditions:
- Input Voltage Range: 9 V to 16 V (Typical: 13.5 V)
- LED Forward Voltage:
- At startup: Min 1.85 V, Typ 2.09 V, Max 2.45 V
- At 30th minute: Min 1.90 V, Typ 2.14 V, Max 2.50 V
- Ambient Temperature: Initially constant at 25°C
- LED Solder Point Temperature: Starts at 30°C and reaches 60°C after 30 minutes
- Output Current Requirements:
- Initially: 220 mA
- At 30th minute: 300 mA
- Thermal Derating Requirement:
- If ambient temperature exceeds 55°C, the output current should be derated to not less than 40% of the active current level, up to 85°C
- Note: The input voltage remains constant at 13.5 V after the initial 30 minutes
I would like to understand how to configure the LP8868-Q1 to meet these requirements. Specifically:
- How can I implement the dual-current profile using temperature feedback (e.g., via TEMP or RTEMP pins)?
- Can the thermal foldback feature be customized to support the described derating behavior?
- Are there any reference designs or application notes demonstrating similar functionality?
Your guidance on configuring the LP8868-Q1 for this application would be greatly appreciated.
Best regards,
RAVIKRISHNAN Gokul
