MAX16928: Automotive TFT-LCD Display Power Solution

Maxim's MAX16928 is an automotive TFT-LCD display power solution with a boost converter and gate voltage regulator, integrating a boost converter, a 1.8V/3.3V regulator controller and two gate voltage regulators (one 28V provides 20mA, one negative gate voltage). With a high-power boost output of up to 6W, an output voltage of up to 18V and an operating frequency of 2MHz, it is mainly used in automotive instrument panels, information displays and navigation systems.

MAX16928 is a highly integrated power supply suitable for automotive TFT-LCD applications. The device integrates a boost converter, a 1.8V/3.3V regulator controller, and two gate voltage regulators. The device is available in multiple versions to meet the requirements of general automotive TFT-LCD power supplies. The boost converter uses spread spectrum modulation to reduce spike interference and optimize EMI performance. The sequencing input (SEQ) allows for more flexible sequencing of the positive and negative gate voltage regulators. The power good indicator (PGOOD) can indicate a fault in any converter or regulator output. The integrated thermal shutdown circuit prevents the device from overheating. The MAX16928 is currently available in a 20-pin TSSOP package with an exposed pad and operates over the -40NC to 105NC temperature range.

Figure 1 MAX16928 Typical Application Circuit

Figure 2 MAX16928 Boost Converter Functional Block Diagram

MAX16928 Key Features

• High power (up to 6W) boost output voltage up to 18V

• 1.8V or 3.3V regulator External NPN transistor, can provide 500mA

• A positive gate voltage regulator, capable of outputting 20mA at 28V

• A negative gate voltage regulator

• Operates at 2.2MHz

• Flexible independent sequencing

• True Shutdown Boost Converter

• Internal soft start

• Thermal shutdown

• Operates over -40NC~105NC temperature range

• Meets AEC-Q100 standards

MAX16928 Applications

• Automotive instrument panel

• Automotive central information display

• Automotive navigation system

MAX16928 Evaluation Board

The MAX16928 Evaluation Kit (EV kit) is a fully assembled and tested surface mount PCB that provides the required voltages and functions for automotive thin-film transistors (TFTs) and liquid crystal displays (LCDs). The evaluation board includes a boost converter and 3.3V regulator controller with external NPN transistor, two gate voltage regulators, a single-stage positive charge pump and a single-stage negative charge pump. The evaluation board operates from an input voltage of 4.5V to 5.5V and is optimized for automotive TFT-LCD applications.

Its boost converter is configured for 12V output and provides a minimum current of 400mA. The output of the regulator controller is 3.3V and provides a minimum current of 500mA. The positive gate voltage regulator provides an 18V output, while the negative gate voltage regulator provides -5.9V.

Figure 3 MAX16928 evaluation board circuit diagram

Figure 4 MAX16928 evaluation board PCB layout diagram Agilent launches a series of new products for radar and defense electronic test and measurement

MAX16928 evaluation board main features

• 4.5V~5.5V input range

• Output voltage:

- 12V output at 400mA (boost converter)

- 3.3V output at 500mA (regulator controller)

-18V output (positive gate voltage regulator)

- -5.9V output (negative gate voltage regulator)

• Can operate at high frequency

- 2.2MHz (boost converter)

• Single-stage positive/negative charge pump

• Proven PCB layout

• Fully assembled and tested