Sony introduces the 'single wire interface
technology' for mobile devices
Sony has introduced the 'single wire interface technology',
a hybrid transmission technology which facilitates both
data and power transmissions through a single cable. This
technology replaces the internal wiring of a mobile device
with a single cable thus making it to be streamlined. Sony
plans to implement this design in mobile devices with movable
mechanisms to improve their design flexibility, reliability
and durability. Conventionally, the video, audio and control
signals as well as the power transmission were spread out
over several dozen cables within the movable mechanisms
of mobile devices, such as hinges or rotating parts.
The advancement in mobile devices have resulted in advanced
functionallities and high resolution display mechanisms
in a mobile system. As a result, more wiring connections
have been used to accommodate the increasing volume of data
being transmitted within devices. Accordingly, new problems
began to emerge as connectors in devices became larger and
the conecting cables had become more difficult to bend.
Sony's 'single wire interface technology' has achieved bi-directional
transmission of several kinds of signals, including video,
audio and control signals, by using time division duplex
and multiplex. In addition, the DC power is supplied on
the same signal cable. Sony's unique encoding technology
with DC balance enables both DC power supply and high speed
data to be transmitted within a limited frequency bandwidth.
In order to swiftly begin practical implementation of this
technology, Sony has teamed up with ROHM Co., Ltd. ('ROHM'),
which has a track record in peripheral technologies, for
the joint development and technical validation for the analog
portion of the test chip. Hereafter, Sony will grant ROHM
a license for the IP of the digital portion of this newly-developed
technology in order to advance the development of a single
chip which includes both the analog and digital portions.
The development process will focus on the following points:
1. Time division duplex and multiplex have enabled bi-directional
transmission of multiple types of data over a single transmission
cable
Sony developed a unique time division duplex and multiplex
method that enable packets of data, including video (display,
camera), audio, and control signals to be transmitted over
a single cable. Furthermore, Sony has enabled the bi-directional
transmission of different signals, such as display and camera
signals, by incorporating a mechanism that retains individual
synchronization.
2. The multi-level encoding technology has enabled higher
transmission rates within the limited signal frequency bandwidth.
The newly-developed hardware is composed of (1) a digital
portion that performs multi-level encoding, (2) an analog
portion that transmits and receives signals, and
(3) another portion that combines signals with DC power
or separates signals from DC power.
A unique multi-level encoding that has no DC component enables
both high speed transmission with limited frequency bandwidth
and DC power supply on a single common cable. Sony has demonstrated
that high transmission speeds (940Mbps) can be achieved.
Technical specifications (tentative values) of the demonstration
system:
Transmission signal :
video (Display / Camera), audio, control signals
Transmission speed :
940Mbps
Power consumption :
10-80mW (0-940Mbps) during transmission, 0.3mW when on stand-by.
Power supply voltage for analog IC : 1.5V/3.0V
Transmission distance :
60cm
Supplied current value :
600mA
Operating ambient temperature :
-20 - +85°C
A comparison with conventional technology:
The wiring between the main body of a mobile phone and
its display section includes display data, camera data,
audio signals, various kinds of sensor data and control
data, and a DC power supply. The table below presents a
comparison of required wiring for conventional technology,
and required wiring for the newly-developed 'single wire
interface technology'.
| |
Number
or wires when wired using conventional technology
|
Number
or wires when wired using this new technology
|
Total
number of wires
(comprising the following:) |
≒22 |
1 |
| Power supply wires
|
1 |
0 |
| Differential wires
|
5 |
1 |
| Audio wires |
1 |
0 |
| Other miscellaneous
wires |
≒15 |
0 |
|
The above estimates assume the following conditions.
• Screen display: WVGA resolution
Built-in camera on display side: VGA resolution
• Includes audio and DC power wiring.
• Has controls for various sensors (two type) such
as the touch panel sensors and receives data.
• Has 4 key switch data acquisition controls and 2
LED flashing controls.
