The latest technology for full high definition large liquid crystal display televisions.

Driven by the popularization of digital broadcasting and diversification of services, liquid crystal display televisions are now being made with screens that are larger and have higher definition as well as greater numbers of colors, with many 50-inch and larger full high definition products on the market.
NEC Electronics has a newly developed interface technology called PPmL™, which allows point-to-point communication between the timing controller IC and LCD driver IC. This technology permits devices to be driven by fewer components, thus contributing to cost reduction.
As a way of promoting standardization of the specifications within the industry, NEC Electronics plans to disclose its PPmL specifications to liquid crystal component manufacturers during new product launching, and will cooperate with other companies.
Details regarding the new PPmL technology from NEC Electronics are given below.


Development background

The wiring length between the timing controller IC and the LCD driver IC in the driving circuit of 45-inch and larger displays commonly exceeds 50 cm, thus making communication difficult via a conventional bus interface.
Problem of very large LCD televisions


One practical solution for shortening the wiring length is to use 2 to 4 timing controller ICs for frequency reduction. This method, however, requires more components, including peripheral flexible printed circuits (FPCs) and connectors, resulting in higher cost.
Practical solutions for very large LCD televisions 1


Wide and long FPCs are used
→Cost increase factor (several million yen)
Practical solutions for very large LCD televisions 2


Dividing the timing controller IC to decrease frequencies and shorten communication distance.
→Very costly


NEC Electronics‘ PPmL technology

PPmL technology is interface technology that allows point-to-point communication between the timing controller IC and LCD driver IC, achieving communication over a longer wiring length. This technology allows control by one timing controller IC, decreasing the number of components in devices, thus contributing to cost reduction.
PPmL solution


The number of pins can be reduced by about half despite there being more FPCs and connectors, thus avoiding higher cost.
Point-to-point connection

In a conventional bus connection (known as the multi-drop method), the number of wires will remain the same even if the number of LCD driver ICs changes. In sum, the effect (load) of the LCD driver ICs commonly connect to the bus line makes it difficult to achieve higher speeds.
Point-to-point connection and bus connection

Bus connection (multi-drop method)

The number of wires remains the same, no matter if the number of LCD driver ICs changes.
Higher speed cannot be readily achieved due to the influence (load) of the commonly connected LCD driver ICs.
Point-to-point connection (one-to-one connection)

Fewer LCD driver ICs mean fewer wires.
One-to-one connection avoids the effect of LCD driver ICs and higher speed can be gained easily.
PPmL features

Higher communication due to point-to-point connection (up to 600 Mps/lane)
The newly developed PPmL technology allows communication between the timing controller IC and LCD driver IC via point-to-point (one-to-one) connections. This technology achieves high-speed communication because communication is not influenced by LCD driver ICs, regardless of wiring length.
Devices can therefore be controlled by one timing controller IC, with the results being the need for fewer components for driving and reduced costs. Standards which flexibly support display resolution (WXGA, full high definition)
PPmL achieves, in a chip which is the same size as a conventional liquid crystal display driver, a linear output function that allows the characteristics to be changed via software, to meet the needs of the liquid crystal display to be manufactured.
Liquid crystal display manufacturers can use the same liquid crystal display LCD driver IC in a wide variety of displays, without a need to change the peripheral components. In contrast to conventional methods wherein a different liquid crystal LCD driver IC is used for each liquid crystal display, production and component management can be more efficient. Adopting standard physical layers (mini-LVDS) (Implementing in silicon eased (development TAT reduction))
The newly developed PPmL adopts standard physical layers (mini-LVDS). This allows crystal display manufacturers to easily implement in silicon and contributes to shortened development TAT.


Introduction of new products

Main features of µPD160290

On-chip PPmL interface
On-chip mini-LVDS (switcheable)
Programmable gamma control possible by on-chip 12-bit linear D/A converter when combined with timing controller IC.
Multi-output of 720 channels allows full high definition configuration with eight controllers or WXGA configuration with six controllers.
Moving video response can be improved with a black insertion function.
µPD160290 product overview

Parameter Specification
Logic power supply voltage 3.0 V to 3.6 V
Liquid crystal driving power supply voltage 10 V to 16.5 V
Interface (mini-LVDS and new PPmL interfaces are mounted) Mini-LVDS: 6 pairs, µPD160015 upward compatible (communicating upper 6 bits and lower 6 bits as two pairs)
Point-to-point: mini-LVDS 1 pair, 12-bit serial 1-pair communication
Clock frequency 280 MHz (max.)
Number of outputs 720/702/690/642
Polarity inversion function Horizontal: Dot inversion, 2H dot inversion
Vertical: Arbitrary
D/A converter resolution 12-bit linear (+12 bits, -12 bits)
Gray scale power supply 18 (for voltage stabilization)
Black insertion function 000H or FFFH black can be output at arbitrary timing
Press release

NEC Electronics Introduces New LCD Driver IC and Interface Technology for Large, Flat-Panel Televisions (18 Apr, 2006)