ROHM's New Automotive Monolithic LED Driver that Ensures Stable Lighting Even During Battery Voltage Drops - Seite 2

 

Key Features

1. Monolithic design ensures stable lighting during battery voltage drops 

The BD18336NUF-M is the first single-chip (ultra-compact 3.0mm square package) IC to incorporate a current bypass function that enables stable lighting during battery voltage drops. The following features (1-1, 1-2) contribute not only to stable lighting, but greater miniaturization as well in the latest socket-type LED lamps.

 

1-1. Maintains at least 30% brightness at all times even when the vehicle battery voltage decreases to 9V

Vehicle batteries normally supply a voltage of 13V (12V considering the backflow protection diode), but the output can vary due to various factors. With conventional products, when the voltage drops to as low as 9V, unless an external circuit is configured, the LEDs may turn OFF, which can cause problems by creating an unsafe situation when driving.

In contrast, ROHM's new IC includes a current bypass function at voltage drops that makes it possible to smoothly switch the LED lighting path through which current flows from 3 lamps to 2 without flickering when the supply voltage from the vehicle battery drops to 9V, contributing to stable lighting that prevents LED turn OFF while maintaining at least 30% brightness at all times (vs the normal ratio). This function can be configured using 3 external resistors (for the operating start voltage and operating interval), providing greater flexibility for a wide range of applications.

 

1-2. Reduces mounting area by 30% over conventional solutions, enabling support for ultra-compact socket-type LED lamps

The built-in current bypass function ensures stable driving during battery voltage drops that reduces the number of external parts by 7 over conventional designs, making it possible to decrease mounting area by up to 30% (including external circuitry). While conventional products may cause the LEDs to blink if configured without external circuitry (comprised of comparators, transistors, and other components) when the battery voltage drops, ROHM’s new IC makes it easy to stably light up LEDs with a single chip. This enables mounting on 10mm square LED module substrates, allowing the configuration of ultra-compact LED lamps that could not be achieved in the past.