Automotive backlight driver sustains brightness even during cold crank
Believed to be the only integrated device which retains full, constant brightness of in-car displays even during extreme cold crank conditions down to 3V input voltage, the four-channel, low-voltage MAX25512 automotive LED backlight driver is available from Maxim Integrated. The single chip LED driver has an integrated boost converter and eliminates the need for an external MOSFET and current sense resistor. It also integrates I²C communication. The I²C communication interface is for display settings and diagnostics and there is a hybrid dimming function to reduce electromagnetic interference (EMI) and improve the dimming ratio.
The result is a lower bill of materials cost and board space is reduced by 30 per cent. The LED driver includes four 120mA channels with what Maxim claims is the industry’s highest efficiency at 2.2MHz operation.
The MAX25512 LED backlight driver addresses the common design dilemma of today’s automotive start-stop systems which increase fuel economy but can challenge the power delivery system to maintain the same level of display brightness during re-start. Features like display illumination upon entry can be affected by cold crank situations, for example, as the engine draws down the car battery to cause the display to turn off and back on. The MAX25512 LED backlight driver operates down to 3.0V after start up without the addition of a pre-boost converter, protecting the display from these power disruptions.
The low, 3.0V input voltage and high, 91 per cent 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 ground 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, says Maxim.
The MAX25512 is offered in a small 24-pin, 4.0 x 4.0 x 0.75mm quad flat no-lead (QFN) package.
The MAX25512 backlight LED driver and associated MAX25512EVKIT# evaluation kit are available now from Maxim Integrated and authorised distributors.
