LED drivers can be used standalone or integrated into ADAS
Two LED driver ICs from Allegro MicroSystems, are designed to reduce the number of ICs ICs required to create safety-enhanced automotive lighting systems, enabling higher performance and more compact designs at lower system cost, says the company.
The A80803 automatically manages the electrical transition from low to high beam, without the need for multiple LED drivers and local microcontrollers. The A80804, provides lighting designers a cost-effective way to enable animations and other lighting effects in a way that simplifies the design process while enhancing visibility and driver safety, as well as minimising bills of materials, says Allegro.
The A80803 leverages multi-topology conversion and patented IP to enable smooth high/low/high beam transitions in a single IC. The A80804 linear LED driver provides high power for automotive lighting applications through multiple, independently-configurable channels.
Vehicle lighting plays a key role when it comes to driver and passenger safety. ADAS applications and lighting enhancements that improve night-time road and vehicle visibility can significantly improve driver response times, to help prevent crashes and save lives.
The A80803 is a switch-mode, constant-current controller for high-power LED automotive lighting applications. The multi-topology single-ended controller design, combined with wide I/O voltage capability has options for SPI-based control or EEPROM-based end-of-line programming for standalone operation.
The A80804 is Allegro’s first four-channel linear driver for high-power LEDs. In addition to targeted applications such as DRL/position and stop/tail or brake lights, it gives lighting designers the flexibility for popular features such as sequential turn signals, animation effects, and theatre-style transitions. No switching elements or inductors are required, and the A80804’s low EMI output helps it achieve CISPR25 Class 5 compliance. The IC also offers multiple analogue and PWM dimming methods, dual brightness mode operation, and is configurable without the need for a
The A80803 includes multi-topology high/low beam switchover, removing the need for a second LED driver IC and a slew-control feature that minimises LED current over- and under-shoot while transitioning between high and low beams. Two configuration options are available: a factory-programmed EEPROM to remove the need for a local microcontroller and an SPI for control and status registers to enable software control. There are also diagnostics for ASIL capability, with two programmable fault pins and reporting via SPI.
There are also multiple methods for analogue LED setting/control for base intensity, foldback for thermal conditions via NTC, or using a single design with different LED “bins”. PWM LED control can be via an internal PWM signal (standalone mode) or an external PWM signal for direct PWM control on the EN/PWM pin (MCU mode).
The A80804 provides linear control over four channels, each with an independent enable/PWM input. PWM LED control can be via an internal PWM signal (standalone mode) including automatic phase shifting, or an external PWM signal for direct control on the EN/PWM pin (MCU mode).
The IC also has the ability to switch between low and full intensity for applications including stop/tail or DRL/position lighting, without the need of a local microcontroller. A selectable LED current slew-rate control tunes PWM edge times, improving EMI performance. Analogue LED setting/control, LED binning, NTC foldback, or hybrid dimming options are offered. The IC also has integrated/optional derating for high Vin and/or temperature. A “MINOUT” function is claimed to significantly reduce power losses by dynamically adjusting for the inherent changes in LED Vf versus temperature. The ICs can be paralleled to extend the number of strings.
The A80803 is available in a thermally enhanced 32-pin 5.0 x 5.0mm QFN package with wettable flank. The A80804 is available in a 32-pin 5.0 x 5.0mm QFN package with wettable flank.
