Renesas Electronics Corporation announced the availability of its new control IC (part number PD168891) for automotive light-emitting diode (LED) headlights.
The main features of the PD168891 IC are (1) an integrated current-control function for constant-current drive of LEDs and a pre-driver function for driving external metal-oxide-semiconductor field-effect transistors (MOSFETs); (2) integrated protection functions essential for automotive applications, including LED current and external MOSFET overcurrent protection; and (3) a newly developed compact package with low thermal resistance. The new device can be combined with other devices, such as MOSFETs, Schottky diodes, and choke coils to build electronic-control units for LED headlights in automobiles.
The PD168891 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.
Main functions of the control IC
(1) Integration of functions specifically for automotive LED headlight applications
The PD168891 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 in case of protection works.
(2) Integration of multiple protection functions
The PD168891 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 PD168891 control IC uses a newly designed compact package (48-pin VQFN, 7 millimeters (mm) x 7 mm, lead-free) with low thermal resistance, making it possible to build automotive control units that are more compact and lightweight.
Pricing and Availability
Samples of Renesas Electronics' new PD168891 control IC are currently available. Sample pricing begins at US$5.00 for 100-piece quantities. Mass production is scheduled for first half fiscal 2012.