Date: 20/05/2012

LED driver from New Japan Radio for backlighting of medium/small sized LCDs in cars

New Japan Radio Co., Ltd. (New JRC) has introduced to the market the NJW4605, LED driver for backlight of medium/small sized LCD panels suitable for in-car equipments such as car navigation system, rear entertainment monitors and so on.

The NJW4605 consists of three constant current drivers and a step-up switching regulator allowing up to 24 LEDs driving. Various controls such as LED current control, error detection etc. by microcomputer are available though the I2C serial interface.

The NJW4605 offers high accuracy brightness control and high accuracy LED string current and string-to-string tolerance both kept within ±2.0% (max.), which can reduce uneven coloring caused by the characteristics variation between LEDs.

NJW4605 is especially suitable for LCD panel requiring high quality in color rendition.

When changing LED brightness, the NJW4065 automatically generates the interpolated value between previous brightness and newly brightness set by CPU. It generates interpolated dimming PWM pulse by up to 1,024-step, which can offer natural brightness control without CPU stress.

Internal step-up switching regulator with external clock synchronous function can reduce interference by radio waves, because the external clock minimizing radio wave interference can be input from host CPU. Therefore the NJW6405 is suitable for in-car equipments such as car navigation systems.

Feature and Characteristics:
Wide operating voltage range: 6.0V to 30V
Operating temperature range: -40°C to +105°C
I2C serial interface
3-Chanel constant current driver: 10mA to 80mA/ch.
High accuracy LED current: ±2% max. (@ILED=40mA)
Switching frequency: 300kHz to 1MHz
PWM brightness control
FAULT signal output
Protection circuits
LED open/short protection, over-current protection, over-voltage protection,
UVLO(Under Voltage Lockout), thermal shut down
Package outline SSOP32 (11.0 × 7.6 × 1.25mm)