CN2824465Y

CN2824465Y - Level converting circuit for TV set

Info

Publication number: CN2824465Y
Application number: CNU200520088173XU
Authority: CN
Inventors: 谢红军; 林勇鹏; 杨勇
Original assignee: Hisense Electric Co Ltd; Hisense Co Ltd
Current assignee: Hisense Electric Co Ltd; Hisense Co Ltd
Priority date: 2005-10-18
Filing date: 2005-10-18
Publication date: 2006-10-04
Anticipated expiration: 2015-10-18

Abstract

The utility model discloses a kind of level shifting circuit of television set, the LVDS interface that comprises television set main control chip and display screen, by between the LVDS of television set main control chip and display screen interface, setting up level transferring chip, the Transistor-Transistor Logic level of main control chip output is converted to the LVDS level, thereby solved the unmatched problem of TV SKD and display screen interface, the electromagnetic radiation of Transistor-Transistor Logic level also solved simultaneously owing to can realize complicated function by simple circuit configuration.Circuit structure of the present utility model is simple and reliable, and is with low cost, has important practical application meaning aspect consumer electronics.

Description

The level shifting circuit of television set

Technical field

The utility model relates to a kind of improvement of TV set circuit, specifically, relates to a kind of TV set circuit that is used for and realizes the change-over circuit of Transistor-Transistor Logic level to the LVDS level.

Background technology

Along with the develop rapidly of TV tech, panel TV is more and more universal, and the interface of various display terminals also is not quite similar, and what the display screen that has adopted is the TTL interface, and what the display screen that has adopted is the LVDS interface.But for the control chip of various mainboards, its interface that is connected with display screen also has nothing in common with each other, and has plenty of the TTL interface, has plenty of the LVDS interface.If main control chip output is Transistor-Transistor Logic level, and the display screen configuration is the LVDS interface, and this just need set up the matching problem that a level transferring chip solves main control chip and display screen interface.Simultaneously, also can reach the purpose that reduces electromagnetic interference EMI to the conversion of LVDS level by carrying out Transistor-Transistor Logic level.

Summary of the invention

The utility model is for the unmatched problem of incoming level of the display screen interface of the output level that solves television set main control chip in the prior art and its configuration, a kind of novel TV machine level shifting circuit is provided, realized conversion with simple circuit configuration from Transistor-Transistor Logic level to the LVDS level, the level signal of television set main control chip output can normally be received by display screen interface, also played the effect that reduces the EMI radiation simultaneously.

For solving the problems of the technologies described above, the utility model is achieved by the following technical programs:

A kind of level shifting circuit of television set, the LVDS interface that comprises television set main control chip and display screen, between the LVDS interface of described television set main control chip and display screen, be connected with a level shifting circuit, the input of described level shifting circuit links to each other with R, G, B signal output part, row, field sync signal output, data enable signal output and the clock differential signal output of television set main control chip respectively, after the Transistor-Transistor Logic level of television set main control chip output is converted to the LVDS level, connect the LVDS interface of display screen by its output.

As the further qualification to technique scheme, described level shifting circuit is connected the LVDS interface of described display screen by 4 pairs of image difference signal output parts and 1 pair of clock differential signal output.

As the further qualification again to technique scheme, it is the LVDS level transferring chip realization of DS90C385 that described level shifting circuit adopts a model.

Compared with prior art, advantage of the present utility model and good effect are: the utility model is by setting up level transferring chip between the LVDS of television set main control chip and display screen interface, the Transistor-Transistor Logic level of main control chip output is converted to the LVDS level, thereby solved the unmatched problem of TV SKD and display screen interface, the electromagnetic radiation of Transistor-Transistor Logic level also solved simultaneously owing to can realize complicated function by simple circuit configuration.Circuit structure of the present utility model is simple and reliable, and is with low cost, has wide application value.

Description of drawings

Fig. 1 is the inside schematic diagram of the utility model level transferring chip;

Fig. 2 is the annexation figure of level transferring chip and television set main control chip and display screen interface in the utility model.

Embodiment

Below in conjunction with the drawings and specific embodiments the utility model is done explanation in further detail.

LVDS (Low Voltage Differential Signaling) is a kind of little difference of vibration sub-signal technology, uses low-down range signal (about 350mV) by a pair of difference PCB cabling or parallel cable transmission data.Fig. 1 is based on the inside schematic diagram of the level transferring chip DS90C385 of LVDS technology, and its driver drives a pair of differential signal line by a constant-current source (being generally 3.5mA) and forms.At receiving terminal a high direct current input impedance is arranged, hardly can current sinking, 100 ohm the terminal resistance so most drive current will be flowed through produces the voltage of about 350mV at the receiver input.When driving condition reversed, the sense of current of the resistance of flowing through changed, so produce effective " 0 " or " a 1 " logic state at receiving terminal.

In order to solve the matching problem of television set main control chip and display screen interface, described LVDS level transferring chip DS90C385 is connected between the LVDS interface of television set main control chip and display screen, its concrete annexation is referring to shown in Figure 2.

Among Fig. 2,24 R of television set main control chip (HOST GRAPHIC CONTROLLER), G, B data-signal output (each data-signal accounts for 8), the line synchronizing signal output, the field sync signal output, data enable signal output and clock signal terminal respectively with the RED of described level transferring chip DS90C385, GRN, BLU picture signal input, HSYNC, VSYNC, DATAENABLE and the corresponding connection of CLOCKIN end, under the control action of main control chip control signal, the Transistor-Transistor Logic level of main control chip output is converted to the LVDS level, link to each other with the LVDS interface of display screen with 1 couple of clock differential signal output CLOCK (LVDS) by its 4 couples of image difference signal output part DATA (LVDS), output LVDS picture signal and clock signal, carry out of the conversion of LVDS level again in display screen PANEL inside to Transistor-Transistor Logic level, come a row matrix of control display screen, and then realize the reliable output of image on display screen.

The utility model has not only been realized the conversion of Transistor-Transistor Logic level to the LVDS level by adopting above-mentioned simple circuit configuration, solved the matching problem of television set main control chip and display screen interface, but also effectively reduce the radiation effect of EMI, aspect consumer electronics, have important practical application meaning.Certainly; above-mentioned explanation is not to be to restriction of the present utility model; the utility model also is not limited in above-mentioned giving an example, and variation, remodeling, interpolation or replacement that those skilled in the art are made in essential scope of the present utility model also should belong to protection range of the present utility model.

Claims

1. the level shifting circuit of a television set, the LVDS interface that comprises television set main control chip and display screen, it is characterized in that: between the LVDS interface of described television set main control chip and display screen, be connected with a level shifting circuit, the input of described level shifting circuit respectively with the R of television set main control chip, G, the B signal output part, OK, the field sync signal output, the data enable signal output links to each other with clock differential signal output, after the Transistor-Transistor Logic level of television set main control chip output is converted to the LVDS level, connect the LVDS interface of display screen by its output.

2. the level shifting circuit of television set according to claim 1, it is characterized in that: described level shifting circuit is connected the LVDS interface of described display screen by image difference signal output part and clock differential signal output.

3. the level shifting circuit of television set according to claim 2, it is characterized in that: the image difference signal output part of described level shifting circuit has 4 pairs, and clock differential signal output has 1 pair, connects the LVDS interface of described display screen respectively.

4. the level shifting circuit of television set according to claim 3 is characterized in that: it is that the LVDS level transferring chip of DS90C385 realizes that described level shifting circuit adopts a model.