Automatic Headlamp On and Day Running Light

Implement Automatic Headlamp On (AHO) and Day Running Light (DRL) Solution with Increased Fuel Efficiency and Improved Safety

Renesas offers a reference solution for Automatic Headlamp On (AHO) / Day Running Light (DRL) with the low power RL78/F12 series microcontroller and Intelligent Power Devices (IPD) to drive headlamp, tail lamp and tell tale indicators.

Automatic Headlamp On (AHO) / Day Running Light (DRL) is developed to keep the headlamp ON during the ignition ON of a vehicle. This reference design complies with upcoming safety standards for two wheelers. The specifications defined for the reference design are based on the inputs from an Indian two wheeler OEM.

The low power automotive microcontroller RL78/F12 series and IPDs are used for the functional requirement. The reference design unique approach also targets to maintain the overall fuel efficiency even while the electrical load is increased due to the Always ON function of the headlamp. In addition, the design also considers load on the battery during engine idling state.

Block Diagram

Key Features
  • Automatic Headlamp ON with detection of Bike ON state
  • RPM based Interlock for Headlamp
  • Compatible with 12 Volts and 5 Volts PWM and Pulse based RPM signal
  • PWM based Lamp intensity control for dimming to save power
  • Programmable Short Circuit and Overcurrent protection
  • Load dump protection up to 42 Volts
Recommended Products
  • Microcontroller: RL78/F12 (R5F10968)
  • IPD: UPD166029
  • IPD: UPD166031 
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