Renesas Electronics Introduces New Control IC for Automotive LED Headlights

The new device can be combined with other devices, such as MOSFETs, Schottky diodes, and choke coils, to build electronic-control units for driving LED headlights, such as automotive headlights.

The μPD168891 device is designed to satisfy the requirements of automotive headlight applications by integrating functions required for LED constant current drive as well as other functions.

The main functions of the control IC are as follows:

1) Integration of functions specifically for automotive LED headlight applications

The μPD168891 device can provide constant-current drive control for up to 12 power LEDs connected in a series. The voltage boost switching frequency can be set to a maximum of 500 kilohertz (kHz), a rate slightly lower than the AM radio frequency band, to prevent interference with the car audio system. LED drive is supported for power-supply voltages ranging from 6 volts (V) to 28V. An integrated pre-driver circuit can drive two power MOSFETs used for voltage boost drive and current line cutoff when protection functions are enabled.

2) Integration of multiple protection functions

The μPD168891 device incorporates several protection functions including overcurrent protection for the LED current and external MOSFETs, over voltage/load (LED) open protection, LED pin short-circuit protection and overheating protection.

A diagnostic function can output information on the device state when a protection function is triggered by a malfunction and a shutoff function controls external power MOSFETs to disable current lines. These functions enable a higher-level unit, such as a body control module, to monitor the state of the electronic-control unit and prevent secondary problems due to continuing current flow.

3) Newly developed compact VQFN package with low thermal resistance

To reduce heat generation and board dimensions, the μPD168891 control IC utilizes a newly designed compact package (48-pin VQFN, 7 millimetres (mm) × 7 mm, lead-free) with low thermal resistance, making it possible to build automotive control units that are more compact and lightweight.