Video connectors are often subject to interference from ESD/EOS static electricity, such as electrostatic surges caused by thunderstorm weather or electrostatic events occurring during hot-plugging processes. If the connector is not protected against ESD/EOS, it can lead to abnormal video output: inability to display images, color abnormalities, and flickering screens. In severe cases, it may be necessary to have a professional replace the video output chip, and in some cases, the television connected to this connector can be burned out. Such situations should be avoided whenever possible.
Figure 1: Application diagram of JY Electronics’ product
Different display connectors have varying signal paths and control paths, and the rate at which they transmit signals also differs. This results in different process technologies and ESD tolerances for the control chips of each connector. Therefore, different connectors require the selection of different ESD protection chip sets for effective ESD protection.
VGA Connector
| Product | Package | VRWM (V) | VBR (V) | VC (V) | IR(μA) | Cj.(pF) |
| TT0514TL | SOT23-6L | 5 | 6 | 12 | 1 | 0.6 |
As shown in Figure 2, it is a schematic diagram of the VGA connector connected with an ESD protection chip. The left part of the circuit is the video transmission signal port, and the right side is the downstream circuit. JY Electronics recommends using two integrated TVS diode arrays, TT0514TL, for electrostatic surge protection of the VGA connector.
Specific connection method: For the first chip on top, pins “1, 3, 6” are connected to the “RBG (Red, Blue, Green)” signals respectively, pin 2 is grounded, and the remaining two pins can be left floating; For the second TT0514TL chip below, pin 1 is connected to the VSYNC (vertical sync) signal, pin 6 is connected to the HSYNC (horizontal sync) signal, pin 2 is grounded, pin 3 is connected to the IDbit0 signal, pin 4 is connected to the IDbit1 signal, and the remaining pin 5 can be grounded.
When a high voltage is generated from the video signal, this large current can flow through the ESD protection chip to the power ground, and the high voltage is clamped at its clamping voltage VC, thereby protecting the downstream circuit from being damaged by the surge voltage and maintaining the stability of the video signal transmission.
Figure 2: Protection circuit of VGA connector using TT0514TL chip
