The MAX25530 is a highly integrated TFT power supply and LED backlight driver IC for automotive TFT-LCD applications. The IC integrates one buck-boost converter, one boost converter, two gate-driver supplies, and a boost/SEPIC converter that can power one to four strings of LEDs in the display backlight.
The source-driver power supplies consist of a synchronous boost converter and an inverting buck-boost converter that can generate voltages up to +18V and down to -7V. The positive source driver can deliver up to 120mA, while the negative source driver is capable of 100mA. The positive source-driver supply-regulation voltage (VPOS) is set by connecting an external resistor-divider on FBP or through I2C. The negative source-driver supply voltage (VNEG) is always tightly regulated to -VPOS (down to a minimum of -7V). The source-driver supplies operate from an input voltage between 2.8V and 5.5V.
The gate-driver power supplies consist of regulated charge pumps that generate from +28V to -21.5V and can deliver 10mA or more each depending on the exact configuration.
The IC features a quad-string LED driver that operates from a separate input voltage (VBATT) and can power up to four strings of LEDs with 150mA (max) of current per string. The IC features logic-controlled pulse-width-modulation (PWM) dimming, with minimum pulse widths as low as 500ns with the option of phase shifting the LED strings with respect to one another. When phase shifting is enabled, each string is turned on at a different time, reducing the input and output ripple, as well as audible noise. With phase shifting disabled, the current sinks turn on simultaneously and parallel connection of current sinks is possible.
The startup and shutdown sequences for all power domains are controlled using one of the seven preset modes, which are selectable through a resistor on the SEQ pin or through the I2C interface.
The MAX25530 is available in a 40-pin (6mm x 6mm) TQFN package with an exposed pad, and operates over the -40°C to +105°C ambient temperature range.
Applications
- Automotive Central Information Displays
- Automotive Dashboards
- Automotive Head Up Displays
- Automotive Navigation System
