Automotive backlight driver sustains brightness even during cold crank
The single-chip MAX25512 automotive LED backlight driver eliminates an external MOSFET and current sense resistor and integrates I2C communication to lower bill of material cost and reduce board space by 30 percent. The highly integrated LED driver includes four 120-mA channels with what the company says is the industry’s highest efficiency at 2.2-MHz operation.
“Car manufacturers are demanding LED drivers with higher integration to reduce solution cost and PCB area,” says Szu-Kang Hsien, director of business management for the Automotive Business Unit at Maxim Integrated. “Maxim Integrated’s MAX25512 LED driver provides the highest level of integration and efficiency at 2.2MHz switching frequency.”
While today’s automotive start-stop systems increase fuel economy, says the company, they can challenge the power delivery system to maintain the same level of display brightness during re-start. For example, features like display illumination upon entry can be affected by cold crank situations, with the engine drawing down the car battery enough to cause the display to turn off and back on. The MAX25512 LED backlight driver is designed to operate down to 3V after startup without the addition of a pre-boost converter, protecting the display from these power disruptions.
The key advantages of the MAX25512 are offered as:
- Lowest Cold Crank and Start-Stop Voltage: The MAX25512’s low, 3V input voltage and high, 91-percent efficiency at 2.2MHz operation drives full, constant brightness of in-car displays during the most demanding cold crank/start-stop conditions. Diagnostic functions such as SHORT to GND on each current sink alerts the microcontroller and individual channel pulse width modulation (PWM) settings through the I2C interface to ensure a safer and higher quality display.
- Highest Integration: The MAX25512 integrates a boost converter and current sense resistor and eliminates the external MOSFET typically required to drive automotive displays. Additional integration includes an I2C communication interface to display settings and diagnostics, as well as a hybrid dimming function to reduce electromagnetic interference (EMI) and improve the dimming ratio.
- Smallest Solution: Offered in a small 24-pin, 4mm x 4mm x 0.75mm quad flat no-lead (QFN) package, the MAX25512’s high integration shrinks solution size by 30 percent through elimination of external components.
The MAX25512 backlight LED driver and associated MAX25512EVKIT evaluation kit are available now.