CN2912165Y

CN2912165Y - Level switching circuit between bus and TV set having the same

Info

Publication number: CN2912165Y
Application number: CN 200620085262
Authority: CN
Inventors: 张智华; 谢洪军; 夏海斌
Original assignee: Hisense Group Co Ltd; Qingdao Hisense Electronics Co Ltd
Current assignee: Hisense Group Co Ltd; Qingdao Hisense Electronics Co Ltd
Priority date: 2006-06-01
Filing date: 2006-06-01
Publication date: 2007-06-13
Anticipated expiration: 2016-06-01

Abstract

The utility model discloses a level transfer circuit between bus lines and a television with the transfer circuit, comprising a bus line 1 and a bus line 2. The bus lines are connected with various bus line power separately through each pull-up resistor, a MOS tube is connected between the two bus lines, the grid electrode of the MOS tube is connected with one of the bus line powers, the source electrode and the drain electrode are connected between the two bus lines. A short circuit selective circuit is connected with the source electrode and the drain electrode of the MOS tube in parallel, and when the levels between the bus line 1 and the bus line 2 are incompatible, the short circuit is disconnected; when the levels between the bus line 1 and the bus line 2 are compatible, the short circuit is connected, and source electrode and the drain electrode of the MOS tube is short circuited. The circuit structure of the utility model is simple and reliable, the volume is small, and the utility model realizes level transfer with minimum influence under the condition of almost no power consumption and delay time to ensure the working stability of the main machine effectively.

Description

Level shifting circuit between bus and have the television set of described change-over circuit

Technical field

The utility model belongs to the TV set circuit technical field, specifically, relates to a kind of change-over circuit of level when being applied in the TV set circuit to realize interface between the different bus.

Background technology

At present, level shifting circuit commonly used generally all is to connect or external diode by interior, and general+5.0V incoming level is converted to+3.3V direct current output realization.But,, especially do not having direct current to arrive under the situation of ground path for high impedance circuit, the capacitive coupling electric charge can make output level be increased to+5V, even is higher than+5V, and the voltage that the result causes circuit output end is about+5.0V, rather than expection+3.3V, do not reach the purpose of level conversion.

Summary of the invention

The utility model is in order to solve in the prior art level shifting circuit at high impedance circuit, especially there be not direct current can not finish the problem of level conversion task under the situation of ground path exactly, level shifting circuit between a kind of novel TV machine bus is provided, with simple circuit configuration, under almost negligible situation of consumed power, time of delay hardly, realize the conversion of bus level with the influence of minimum, thereby effectively guaranteed the stability and the reliability of complete machine work.

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

Level shifting circuit between a kind of bus and have the television set of described change-over circuit, comprise bus 1 and bus 2, the pull-up resistor that described two buses are passed through respectively separately connects different bus power source, between described two buses, be connected with a metal-oxide-semiconductor, the grid of described metal-oxide-semiconductor connects one of them bus power source, and source electrode and drain electrode are connected between two buses.

As further qualification to technique scheme, between the source electrode of described metal-oxide-semiconductor and drain electrode, be parallel with a short circuit and select circuit, when the level between bus 1 and the bus 2 is incompatible, disconnect described short-circuit; When the level between bus 1 and the bus 2 is compatible, be communicated with described short-circuit, with the source electrode and the drain electrode short circuit of metal-oxide-semiconductor.Specifically, described short circuit selects circuit to adopt a resistance to realize, described resistance is connected in parallel between the source electrode and drain electrode of metal-oxide-semiconductor, when the level between bus 1 and the bus 2 is incompatible, described resistance is set is tending towards infinitely great; When the level between bus 1 and the bus 2 is compatible, described resistance is changed to 0V.

As to further the limiting again of technique scheme, described metal-oxide-semiconductor is a N channel enhancement metal-oxide-semiconductor, and the less bus power source of its grid and magnitude of voltage links to each other, the bus that the drain electrode connection links to each other with described bus power source, and source electrode connects another bus.Specifically, bus 1 is through pull-up resistor connection+5V bus power source, and bus 2 is through pull-up resistor connection+3.3V bus power source, and the grid of described metal-oxide-semiconductor connects described+3.3V bus power source, drain electrode connecting bus 2, source electrode connecting bus 1.

Compared with prior art, advantage of the present utility model with good effect is: the NMOS pipe BSN20 of the low on-resistance of the utility model by adopting a special use between different buses realizes the level conversion between bus, have that circuit structure is simple, volume is little, can be under almost negligible situation of consumed power, time of delay hardly, realize the conversion of bus level with the influence of minimum, thereby effectively guaranteed the stability and the reliability of complete machine work.

Description of drawings

Fig. 1 is the level shifting circuit schematic diagram between bus in the utility model.

Embodiment

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

In order to realize the mutual conversion of level between different bus, level shifting circuit between the bus that a kind of N of employing channel enhancement metal-oxide-semiconductor BSN20 realizes is provided in the utility model, this circuit mainly is made up of NMOS pipe BSN20, resistance R 001, R004 and R006 etc., and particular circuit configurations is referring to shown in Figure 1.

Among Fig. 1, bus B US1 is through pull-up resistor R004 connection+5V DC power supply, and bus B US2 connects NMOS pipe BSN20 through pull-up resistor R001 connection+3.3V DC power supply between BUS1 and the BUS2.Wherein, the grid 1 of NMOS pipe BSN20 connects described+3.3V DC power supply, and drain electrode 2 connects BUS2, and source electrode 3 connects BUS1.At the source electrode 3 of described NMOS pipe BSN20 with drain and be parallel with a resistance R 006 between 2, select its resistance according to the compatible state of bus level.

When the level of bus B US1, BUS2 was incompatible, off resistance R006 or the resistance of resistance R 006 strengthened as far as possible preferably was tending towards infinitely great.If BUS1 is last is high level+5V, then the V of NMOS pipe BSN20 _GS=-1.7V, so NMOS pipe BSN20 ends, the high level of the last output of BUS2 is+3.3V; If going up, bus B US1 is low level OV, the V of NMOS pipe BSN20 _GS=+3.3V, thus NMOS pipe BSN20 conducting, V _DS=O, it is OV that bus B US2 goes up output low level, thereby realizes the level conversion between double bus.When level is compatible between the two-way bus, the resistance of resistance R 006 can be arranged to 0V, make source electrode 3 and drain electrode 2 short circuits of NMOS pipe BSN20 with this.

The utility model has been realized the conversion of level between different bus by adopting above-mentioned simple circuit configuration, and the bus switch circuit that provides is reliable and stable, has greatly improved the stability and the reliability of system's operation.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 between a bus, comprise bus 1 and bus 2, the pull-up resistor that described two buses are passed through respectively separately connects different bus power source, it is characterized in that: between described two buses, be connected with a metal-oxide-semiconductor, the grid of described metal-oxide-semiconductor connects one of them bus power source, and source electrode and drain electrode are connected between two buses.

2. the level shifting circuit between bus according to claim 1 is characterized in that: be parallel with a short circuit and select circuit between the source electrode of described metal-oxide-semiconductor and drain electrode, when the level between bus 1 and the bus 2 is incompatible, disconnect described short-circuit; When the level between bus 1 and the bus 2 is compatible, be communicated with described short-circuit, with the source electrode and the drain electrode short circuit of metal-oxide-semiconductor.

3. the level shifting circuit between bus according to claim 2, it is characterized in that: it is a resistance that described short circuit is selected circuit, described resistance is connected in parallel between the source electrode and drain electrode of metal-oxide-semiconductor, when the level between bus 1 and the bus 2 is incompatible, described resistance is set is tending towards infinitely great; When the level between bus 1 and the bus 2 is compatible, described resistance is changed to 0V.

4. according to the level shifting circuit between claim 2 or 3 described buses, it is characterized in that: described metal-oxide-semiconductor is a N channel enhancement metal-oxide-semiconductor, the less bus power source of its grid and magnitude of voltage links to each other, and drain electrode connects the bus that links to each other with described bus power source, and source electrode connects another bus.

5. the level shifting circuit between bus according to claim 4, it is characterized in that: bus 1 is through pull-up resistor connection+5V bus power source, bus 2 is through pull-up resistor connection+3.3V bus power source, the grid of described metal-oxide-semiconductor connects described+3.3V bus power source, drain electrode connecting bus 2, source electrode connecting bus 1.

6. television set with level shifting circuit between the described bus of claim 1, comprise bus 1 and bus 2, the pull-up resistor that described two buses are passed through respectively separately connects different bus power source, it is characterized in that: between described two buses, be connected with a metal-oxide-semiconductor, the grid of described metal-oxide-semiconductor connects one of them bus power source, and source electrode and drain electrode are connected between two buses.

7. television set according to claim 5 is characterized in that: be parallel with a short circuit and select circuit between the source electrode of described metal-oxide-semiconductor and drain electrode, when the level between bus 1 and the bus 2 is incompatible, disconnect described short-circuit; When the level between bus 1 and the bus 2 is compatible, be communicated with described short-circuit, with the source electrode and the drain electrode short circuit of metal-oxide-semiconductor.

8. television set according to claim 7, it is characterized in that: it is a resistance that described short circuit is selected circuit, described resistance is connected in parallel between the source electrode and drain electrode of metal-oxide-semiconductor, when the level between bus 1 and the bus 2 is incompatible, described resistance is set is tending towards infinitely great; When the level between bus 1 and the bus 2 is compatible, described resistance is changed to 0V.

9. according to claim 7 or 8 described television sets, it is characterized in that: described metal-oxide-semiconductor is a N channel enhancement metal-oxide-semiconductor, and the less bus power source of its grid and magnitude of voltage links to each other, and drain electrode connects the bus that links to each other with described bus power source, and source electrode connects another bus.

10. television set according to claim 9, it is characterized in that: bus 1 is through pull-up resistor connection+5V bus power source, and bus 2 is through pull-up resistor connection+3.3V bus power source, and the grid of described metal-oxide-semiconductor connects described+3.3V bus power source, drain electrode connecting bus 2, source electrode connecting bus 1.