CN201156773Y

CN201156773Y - Electronic apparatus having HDMI/USB interface and interface circuit

Info

Publication number: CN201156773Y
Application number: CNU2008200919783U
Authority: CN
Inventors: 江五讲
Original assignee: Shenzhen Coship Electronics Co Ltd
Current assignee: Shenzhen Coship Electronics Co Ltd
Priority date: 2008-01-29
Filing date: 2008-01-29
Publication date: 2008-11-26
Anticipated expiration: 2018-01-29
Also published as: DE202008015802U1

Abstract

The utility model discloses an electronic device and an interface circuit. The electronic device is provided with an HDMI/USB interface, and comprises an HDMI module/USB module which is connected with the host of the device, and a one-way communication module which is connected between the host of the device and the HDMI module/USB module. The one-way communication module comprises triodes (Q1) and (Q2), and resistances (R1) and (R2); the base of the triode (Q1) is connected with a DC power supply through the resistance (R1); the emitter is earthed; and the collector is connected with the base of the triode (Q2) through the resistance (R2). The collector of the triode (Q2) is connected with the power input end of the HDMI/USB module; and the emitter is connected with the host of the device. The electronic device can effectively prevent the external device from reversely providing power for the HDMI module/USB module through the HDMI line/USB line, when the main device is arranged under the false stand-by or powerdown condition, and such condition can result in the loss of the performances of the main device and the damage to the chip. Moreover, the electronic device has the advantages of simple structure and low costs.

Description

A kind of electronic equipment and interface circuit thereof with HDMI/USB interface

Technical field

The utility model relates to the technical field that prevents reverse power supply in the electronic product, especially relates to a kind of electronic equipment with HDMI/USB interface and interface circuit thereof that prevents oppositely power supply.

Background technology

HDMI (High-Definition Multimedia Interface Specification Revision 1.2) has become the standard digital interface of whole world consumption electronic product rapidly.From the set-top box to DVD, DTV, HDMI has become FPD at present, the preferred configuration interface of HDTV television receiver and digital home's movie theatre.

USB (Universal Serial Bus) has been widely used in computer, keyboard, pickup camera, set-top box, products such as external hard disk even display.500 milliamperes electric current can be provided simultaneously, and the smaller equipment of some power consumption just can external power supply.

As shown in Figure 1, be set-top box with HDMI and USB interface power supply power supply schematic diagram when the operate as normal, wherein power module is module for power supply such as CPU, single-chip microcomputer, AV, HDMI, USB.Yet in false standby or outage, under the situation that the ancillary equipment (such as television set) that is connected with its set-top box is still worked or powered on, ancillary equipment can oppositely be powered by HDMI or USB power line, cause the functions of the equipments disappearance of band HDMI interface or USB interface easily, even the defective chip circuit.As shown in Figure 2.

Because HDMI module and USB module generally adopt the self-powered mode, so when device powers down, no matter be main equipment or slave unit, so long as not outage of the method, apparatus that HDMI or USB connect, and the opposing party's equipment has cut off the power supply or false standby, and the equipment that does not have an outage all can be by the HDMI line that connects or USB line to power cutoff device or the false module for power supply for the treatment of the employing 5V power supply of machine equipment.When oppositely powering,, the module that adopts the 5V power supply is impacted, cause set-top box partial function disappearance so long as the module that links to each other with HDMI module or USB module all can be in running order, even defective chip.

The utility model content

Technical problem to be solved in the utility model provides a kind of HDMI/USB interface circuit, it can effectively avoid electronic equipment to cause that under the situation of false standby or outage HDMI module or USB module oppositely power, thereby influences functions of the equipments, defective chip, and it is simple in structure, with low cost.

A kind of HDMI/USB interface circuit comprises the HDMI module/USB module of connection device main frame and the unidirectional conduction module between connection and Device Host and the HDMI module/USB module.Wherein said unidirectional conduction module comprises triode Q1, Q2 and resistance R 1, R2, the base stage of described triode Q1 connects DC power supply by resistance R 1, emitter is connected to systematically, collector electrode connects the base stage of triode Q2 by resistance R 2, the collector electrode of triode Q2 is connected HDMI/USB modular power source input, emitter connection device main frame.

Another technical problem to be solved in the utility model provides a kind of electronic equipment of the HDMI/USB of having interface circuit, it can effectively avoid electronic equipment to cause that under the situation of false standby or outage HDMI module or USB module oppositely power, thereby influence functions of the equipments, defective chip, and it is simple in structure, with low cost.

A kind of electronic equipment with HDMI/USB interface circuit, its HDMI/USB interface circuit comprise the HDMI module/USB module of connection device main frame, and the unidirectional conduction module between connection and Device Host and the HDMI module/USB module.Wherein said unidirectional conduction module comprises triode Q1, Q2 and resistance R 1, R2, the base stage of described triode Q1 connects DC power supply by resistance R 1, emitter is connected to systematically, collector electrode connects the base stage of triode Q2 by resistance R 2, the collector electrode of triode Q2 is connected HDMI/USB modular power source input, emitter connection device main frame.

Wherein said electronic equipment is a set-top box.

Compared with prior art, the utlity model has following beneficial effect: by being connected unidirectional conduction module between the power input of HDMI module or USB module and the main frame, thereby effectively avoid main equipment to cause that under the situation of false standby or outage HDMI module/USB module oppositely powers, make the master device functionality disappearance, defective chip, and circuit structure is simple, and is with low cost.

Description of drawings

Fig. 1 is the power supply of the power supply during a set-top box operate as normal schematic diagram in the prior art;

Fig. 2 is the set-top box schematic diagram that ancillary equipment is oppositely powered when false standby or outage in the prior art;

Fig. 3 is that set-top box of the present utility model prevents the oppositely schematic diagram of power supply of ancillary equipment when false standby or outage;

Fig. 4-the 1st, the HDMI interface circuit structure chart of the utility model one embodiment;

Fig. 4-the 2nd, the usb circuit structure chart of the utility model one embodiment;

Fig. 5-the 1st, the HDMI interface circuit structure chart of another embodiment of the present utility model;

Fig. 5-the 2nd, the usb circuit structure chart of another embodiment of the present utility model.

Fig. 6-the 1st, the HDMI interface circuit structure chart of the 3rd embodiment of the present utility model;

Fig. 6-the 2nd, the usb circuit structure chart of the 3rd embodiment of the present utility model.

Embodiment

Below in conjunction with drawings and Examples, the utility model is described in further detail.

The HDMI/UDB interface circuit that the utility model provides mainly is to add unidirectional conduction module between HDMI module/USB module and Device Host, prevents that HDMI module or USB module from oppositely powering.

Below to be applied to set-top box with the utility model be that example describes operation principle of the present utility model in detail.

As shown in Figure 3, after having increased unidirectional conduction module on the HDMI of set-top box module or the USB module, the ancillary equipment of set-top box (such as: television set) when false standby of set-top box or the outage, because the effect of unidirectional conduction module can not (comprise: modules such as CPU, AV, single-chip microcomputer, network, tuner, hard disk, Karaoke) power supply to each module for power supply in the set-top box main frame.

Embodiment 1

As Fig. 4-1, shown in Fig. 4-2, present embodiment preferably adopts Schottky diode as unidirectional conduction module, the power module of its anode junctor top box main frame, negative electrode is connected HDMI module/USB module+5V power input, its forward voltage drop is 0.3V, when the HDMI of set-top box line or USB line are connected communication with television set or other external played equipment, through the voltage behind this Schottky diode is 4.7V, because what HDMI module and USB module were used is the 5V power supply, so but voltage range operate as normal between 4.7V-5.25V.Should export the 5.1-5.25V power supply therefore in set-top box, for the power circuit of HDMI module and USB module for power supply.

In the time of set-top box outage or false standby, because oppositely ending of Schottky diode, the external connection apparatus of set-top box (such as: television set), just can not oppositely power, also just can not influence the module of all 5V power supplies in the set-top box by the power line of HDMI and USB to set-top box.Just can not make because after set-top box outage or the false standby, other 5V supply modules have also just been avoided the influence to STB working status certainly still in work.Simultaneously, can not influence its operating state because of the problem of electrifying timing sequence because of when set-top box re-powers yet.

Embodiment 2

As Fig. 5-1, shown in the 5-2, present embodiment adopts triode and its configuration resistance as unidirectional conduction module, its base stage connects+power supply about 12V, emitter is connected HDMI module/USB modular power source and imports out end, collector electrode connection device main frame, utilize the reverse cut-off characteristics of triode, when making set-top box outage or false standby, the external connection apparatus of set-top box (such as: television set), just can not oppositely power, also just can not influence the module of all 5V power supplies in the set-top box by the power line of HDMI and USB to set-top box.Just can not make because after set-top box outage or the false standby, other 5V supply modules have also just been avoided the influence to STB working status certainly still in work.Simultaneously, can not influence its operating state because of the problem of electrifying timing sequence because of when set-top box re-powers yet.

Embodiment 3

As Fig. 6-1, shown in Fig. 6-2, pressure drop features of smaller when present embodiment utilizes the conducting of PNP triode saturated between collector electrode and emitter, adopt two triodes and configuration resistance thereof as unidirectional conduction module, wherein the base stage of triode Q1 by resistance R 1 connect+power supply about 3.3V or other be higher than+power supply of 0.7V, grounded emitter, collector electrode are connected to the base stage of another triode Q2 by resistance R 2; The collector electrode of triode Q2 is connected HDMI module/USB modular power source input, emitter connection device main frame.Utilize the reverse cut-off characteristics of triode Q2, when making set-top box outage or standby, the external connection apparatus of set-top box (such as: television set), just can not oppositely power, also just can not influence the module of all 5V power supplies in the set-top box by the power line of HDMI and USB to set-top box.Just can not make because after set-top box outage or the standby, other 5V supply modules have also just been avoided the influence to STB working status certainly still in work.Simultaneously, can not influence its operating state because of the problem of electrifying timing sequence because of when set-top box re-powers yet.

The operation principle of its circuit is as follows:

When Device Host powers on and need power to peripheral hardware, at first by+3.3V or other be higher than+power supply of 0.7V opens triode Q1, the collector current that is produced by triode Q1 drives the base stage of triode Q2 then, make triode Q2 be operated in saturation condition, at this moment the voltage difference minimum between the emitter and collector of triode Q2; When Device Host is in standby or outage, external connection apparatus is under the situation about powering on, the power supply of external connection apparatus can pour in down a chimney to the collector electrode of triode Q2, but because this moment, non-transformer drove triode Q1, Q1 is in cut-off state, therefore, can't produce the base stage that electric current drives triode Q2, thereby make triode Q2 be in cut-off state, the power supply of external connection apparatus can't arrive the 5V electric power network of Device Host.Can keep anti-function of pouring in down a chimney like this, the voltage drop in the time of can also reducing the power supply of power supply forward has reduced the loss of power on the one hand, has also prevented on the other hand owing to give the low excessively external connection apparatus work that causes of the supply power voltage of external connection apparatus undesired.This programme adopts positive-negative-positive triode Q2 to do power supply control, and when power supply power supply stream was big, the triode of also optional majority kind model used, and makes things convenient for actual production.

Claims

1, a kind of HDMI/USB interface circuit, the HDMI module or the USB module that comprise the connection device main frame, it is characterized in that: also comprise the unidirectional conduction module between connection and Device Host and HDMI module/USB module, described unidirectional conduction module comprises triode (Q1), (Q2) and resistance (R1), (R2), the base stage of described triode (Q1) connects DC power supply by resistance (R1), grounded emitter, collector electrode connects triode (Q2) base stage by resistance (R2), the collector electrode of triode (Q2) is connected HDMI/USB modular power source input, emitter connection device main frame.

2, a kind of electronic equipment with HDMI/USB interface circuit, its HDMI/USB interface circuit comprises the HDMI module or the USB module of connection device main frame, it is characterized in that: described HDMI/USB interface circuit also comprises the unidirectional conduction module between connection and Device Host and the HDMI module/USB module, described unidirectional conduction module comprises triode (Q1), (Q2) and resistance (R1), (R2), the base stage of described triode (Q1) connects DC power supply by resistance (R1), emitter is connected to systematically, collector electrode connects the base stage of triode (Q2) by resistance (R2), the collector electrode of triode (Q2) is connected HDMI/USB modular power source input, emitter connection device main frame.

3, the electronic equipment with HDMI/USB interface circuit as claimed in claim 2 is characterized in that: described electronic equipment is a set-top box.