Components

PMIC with Programmable Output for Large UHD TV LCD Panels

Silicon Mitus, Inc. launched the SM4805. SM4805 is a highly integrated multi-output PMIC that satisfies UHD TV LCD panel application requirements. The device has an input voltage range of 10.2V to 14.7V, and the company claims that it is the first device of its type that can power large UHD TV LCD panels.

The AVDD boost controller drives the external switches to provide high power at voltages required by the application. Three buck converters regulate output voltages from 0.8V to 3.5V with an output current of up to 2.5A. The power up sequence and the output voltages are programmable through the digital interface.

The SM4805 also features 4-channel gamma buffers and two VCOM op-amps that deliver low noise output.

Despite a high degree of integration, the company notes that the device operates at a lower temperature because of highly efficient dc-dc converters based on specialized IPs.

The SM4805 includes a programmable 7-bit VCOM calibrator with EEPROM for VCOM voltage calibration, seven switching regulators (AVDD boost converter, HAVDD buck converter, VGH boost converter and VGL buck-boost converter), VGL2 negative linear regulator, DVDD1 to 3 buck converters, 4-channel gamma buffers, and dual operational amplifiers.

The AVDD boost converter and the HAVDD buck converter deliver the regulated supply voltage for the panel source driver ICs. The DVDD1 to 3 buck converters provide the supply voltage for the I/O interface, the core of the T-CON and the other logic circuits.

A PG function gives it a reliable power sequence. The company designed the dual high-speed op-amps to drive the LCD backplane with the capability of high current and wide bandwidth.

The VGH boost converter delivers the regulated voltage for the positive gate driving supply, and the VGL buck-boost converter outputs the regulated voltage for the negative gate driving supply. VGH voltage can vary based on the temperature sensed by an external NTC thermistor.

The design compensates all regulators internally except AVDD boost converter, and the all switching converters feature high-efficiency and programmable frequency operation. The high switching frequency of these converters enables the use of ultra-small inductors and ceramic capacitors.

In addition to a true shutdown function of the AVDD boost converter, the device has a GPM function that reduces image sticking and enhances display quality.

Silicon Mitus optimized the PMIC for TFT LCD applications.

“With heightened levels of power consumption and power rails in UHD TV LCD panels, LCD panel PMICs require higher output power and integration with higher efficiency at lower IC temperatures. We are proud to offer the SM4805 that makes this possible as part of the Silicon Mitus TV LCD PMIC exhaustive portfolio,” said Henry Jung, Head of Display Marketing.

Features
  • 10.2V to 14.7V Input Supply Voltage Range
  • Programmable Switching Frequency
  • Asynchronous Boost Converter for AVDD
    • Programmable Output Voltage: 12.8V to 19V
    • Programmable Current Sense Threshold Voltage
  • Forced Synchronous Buck Converter for HAVDD
    • Programmable Output Voltage: 6.4V to 9.5V
    • 1.5A Switch Current Limit
  • 3-Channel Asynchronous Buck Converter for DVDD1, 2, 3
    • Output Voltage: 0.8V to 3.5V
    • 2.5A Switch Current Limit
  • Asynchronous Boost Converter for VGH
    • Programmable Output Voltage: 25V to 43V
    • 2A Switch Current Limit
    • Temperature-compensated Output
  • Asynchronous Buck-Boost Converter for VGL
    • Programmable Output Voltage: -16V to -4V
    • 1.5A Switch Current Limit
  • Negative Linear Regulator for VGL2
    • Programmable Output Voltage: -9V to -3V
    • Internal Transistors for Sinking/Sourcing Output Current
  • Positive Gate Pulse Modulation for VGPM
  • Programmable Four Channel Gamma Reference Voltage Outputs with 9-bit Resolution
  • Programmable VCOM Calibrator with EEPROM
    • 7-bit Adjustable Output Voltage
  • Dual Channel Operational Amplifiers
    • 8-bit Programmable DACs for VCOM 1, 2
  • PG Function for Reliable Power Sequence
  • Programmable Output Voltages and Power-up Sequence Applications
  • Part Package Size: 56 QFN 7mm x 7mm

The device comes in a 56 QFN package, and samples are available.

Silicon Mitus
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