CN201226445Y - High-resolution multimedia interface device and control chip thereof - Google Patents

Abstract

The utility model provides a high-resolution multimedia interface device and control chip thereof. The control chip of the high-resolution multimedia interface device comprises a leakage current protection circuit and a resistive element. The leakage current protection circuit comprises a transistor, wherein a control end of the transistor is used for receiving a control voltage, a first end of the transistor is coupled to a consumer electronic control port, and a second end of the transistor is coupled to the resistive element. Utilize the switching characteristic of transistor, the utility model discloses a leakage current protection circuit can reach the function of leakage current protection effectively, makes the high-resolution multimedia interface device accord with the leakage current standard of stipulating in the agreement. In addition, the leakage current protection circuit is integrated in the control chip, so that the production cost is saved, and the practicability of the control chip and the convenience in hardware implementation are improved.

Description

High resolution multimedia interface device and its control chip

technical field

The utility model relates to a high-resolution multimedia interface (HDMI) device and a control chip thereof, in particular to a high-resolution multimedia interface device including a leakage current protection circuit and a control chip thereof.

Background technique

HDMI is a fully digital image/sound transmission interface that can simultaneously transmit uncompressed (uncompressed) audio and video signals, and all devices compatible with HDMI, such as set-top boxes (set-top boxes), CD players, personal computers , TV game consoles, digital audio and television, etc., can pass the minimum transmission differential signal (Transition-Minimized Differential Signaling) channel, display data channel (Display Data Channel) and consumer electronics control (Consumer Electronics Control) regulated by HDMI. CEC) channel to communicate with each other. Therefore, HDMI has gradually replaced existing analog video and audio transmission interfaces (such as SCART and RCA terminals) in the market.

The consumer electronics control channel is used to transmit AV Link protocol signals so that consumers can control multiple connected HDMI devices from a single remote control to perform functions such as One Touch Play, One Touch Recording, etc. Record), and system standby (System Standby) and other functions. Since the consumer electronics control channel directly connects each HDMI device in the network, the HDMI protocol strictly stipulates the electrical specifications that the consumer electronics control port should comply with, and each HDMI device needs to pass through the consumer electronics. Check the current and voltage value of the electronic control port to avoid damage to other electrical products in the network due to excessive leakage current.

The HDMI protocol stipulates that when the power is turned off, the leakage current shall not exceed 1.8μA, and when the power is turned on, the voltage level of the consumer electronics control port shall be maintained at 3.3V.

Utility model content

In view of this, one of the objectives of the present invention is to provide a leakage current protection circuit applied to a consumer electronic control port of an HDMI device, so that the HDMI device complies with the leakage current specification stipulated in the protocol.

In addition, the leakage current protection circuit of the present invention can be integrated into an HDMI control chip to save production cost, improve the practicability of the control chip and the convenience of hardware implementation.

According to an embodiment of the present invention, an HDMI device is provided. The HDMI device includes a consumer electronics control (CEC) port, a leakage current protection circuit and a resistive element, wherein the leakage current protection circuit includes a transistor, the control terminal of the transistor is used to receive a control voltage, and the first terminal is a coupling Connected to the consumer electronics control port, and the first end of the resistive element is used to receive a predetermined voltage level, and the second end of the resistive element is coupled to the second end of the transistor; wherein, when the HDMI device is a power supply When the power off state is turned off, the control voltage will turn off the transistor, and when the HDMI device is in the power on state, the control voltage will turn on the transistor.

According to another embodiment of the present invention, it provides an HDMI control chip. The HDMI control chip includes a leakage current protection circuit and a resistive element, wherein the leakage current protection circuit includes a transistor, the control terminal of the transistor is used to receive a control voltage, the first terminal is coupled to the consumer electronics control port, and The first end of the resistive element is used to receive a predetermined voltage level, and the second end is coupled to the second end of the transistor; wherein, when the HDMI device is powered off, the control voltage will turn off the transistor, when the HDMI When the device is powered on, the control voltage turns on the transistor.

Description of drawings

FIG. 1 is a schematic diagram of an embodiment in which the leakage current protection circuit of the present invention is applied to a consumer electronics control port of an HDMI device.

FIG. 2 is a schematic diagram of an embodiment of integrating the leakage current protection circuit shown in FIG. 1 , the resistor and an electrostatic discharge protection circuit into an HDMI control chip.

FIG. 3 is a schematic diagram showing how the leakage current protection circuit shown in FIG. 1 achieves the performance of leakage current protection when the system power is turned off.

FIG. 4 is a schematic diagram showing how the leakage current protection circuit shown in FIG. 1 achieves the performance of leakage current protection when the system power supply is turned on.

Description of reference symbols

110 Consumer Electronics Control Port 120 transistor 130 HDMI control chip 140 Electrostatic discharge protection circuit 300, 400 electronic device

Detailed ways

Certain terms are used in the specification and subsequent claims to refer to particular elements. It should be understood by those skilled in the art that hardware manufacturers may use different terms to refer to the same element. This description and subsequent patent applications do not use the difference in name as a way to distinguish components, but use the difference in function of components as a criterion for distinguishing. The "comprising" mentioned throughout the specification and subsequent claims is an open-ended term, so it should be interpreted as "including but not limited to". In addition, the term "coupled" here includes any direct and indirect means of electrical connection. Therefore, if it is described that a first device is coupled to a second device, it means that the first device may be directly electrically connected to the second device, or indirectly electrically connected to the second device through other devices or connection means.

Please refer to FIG. 1 , which is a schematic diagram of an embodiment in which the leakage current protection circuit of the present invention is applied to a consumer electronic control port of an HDMI device. The leakage current protection circuit has the function of a switch. In this embodiment, it is implemented by a transistor (such as the NMOS transistor shown in the figure) 120 . The gate of the transistor 120 is used to receive a control voltage Vc, and the control voltage Vc is related to the power supply of the HDMI device (for example, the control voltage Vc is generated from the power supply of the HDMI device), and the drain of the transistor 120 is coupled to A consumer electronic control port 110, and the source is coupled to a resistor R; the other end of the resistor R is coupled to a predetermined voltage level, in the HDMI protocol, the resistance value of the resistor R is 2.7kΩ, and the predetermined voltage The level is +3.3V.

The leakage current protection circuit and the resistor R of the present invention can be arranged outside an HDMI control chip in the form of an external circuit. In another embodiment, in order to save production costs and improve the convenience of hardware implementation, the above-mentioned transistor 120 and resistor R can be integrated into an HDMI control chip 130. In this way, the practicability of the HDMI control chip 130 can also be greatly increased. Please refer to FIG. 2, an electrostatic discharge (ESD) protection circuit 140 may also be integrated in the HDMI control chip 130. In this embodiment, the electrostatic discharge protection circuit 140 includes a plurality of diodes connected in series, but it is worth noting that, for A path for discharging the predetermined voltage level +3.3V is not formed, and the electrostatic discharge protection circuit is not provided in parallel with the resistor R (a diode shown by a dotted line in the figure).

FIG. 3 is a schematic diagram showing how the leakage current protection circuit 120 achieves the performance of leakage current protection when the system power of the HDMI device is turned off. Since the gate of the transistor 120 is controlled by the control voltage Vc related to the power supply of the HDMI device, when the power is turned off, the control voltage Vc is also at a low voltage level, so that the transistor 120 is turned off. Therefore, the consumer electronics control port 110 An open circuit is formed with the internal circuit of the HDMI device, even if the HDMI device is connected to an electronic device 300 , the consumer electronic control port 110 will not form a leakage current. On the other hand, when the system power is turned on, as shown in FIG. 4 , the control voltage Vc will be at a high voltage level, so that the transistor 120 is turned on, and the transistor 120 can be regarded as a pass. Since the HDMI device does not have an ESD protection circuit connected in parallel with the resistor R, there is no discharge path for the predetermined voltage level +3.3V received by the resistor R. Therefore, when the HDMI device is connected to an electronic device 400, the consumer electronics control The voltage level on the port 110 can be maintained at around +3.3V, which meets the leakage current standard specified by the HDMI protocol.

In the above-mentioned embodiments, the leakage current protection circuit utilizes the switching characteristics of the transistor 120 to effectively achieve the function of leakage current protection. When it is applied to the consumer electronics control port of an HDMI device, it can make the HDMI device comply with the relevant leakage current in the HDMI protocol. Specifications: In the state of power off, the leakage current is less than 1.8μA; in the state of power on, the voltage level is maintained at 3.3V.

In addition, in the above disclosure, it is proposed to integrate the leakage protection circuit into the design of the control chip, which can save the production cost, and make the control chip have the advantages of high practicability and convenient hardware implementation.

The above descriptions are only preferred embodiments of the present utility model, and all equivalent changes and modifications made according to the patent scope of the present utility model shall fall within the scope of the present utility model.

Claims (7)

1. high-definition multimedia interface arrangement is characterized in that comprising:

One consumer electronics control port;

One leakage current protection circuit includes:

One transistor includes a control end, one first end and one second end, and wherein, this control end is used to receive a control voltage, and this first end is coupled to this consumer electronics control port; And

One resistance element includes one first end and one second end, and wherein, this of this resistance element first end is used to receive a predetermined voltage level, and this second end of this resistance element is coupled to this transistorized this second end;

Wherein, when this high-definition multimedia interface arrangement was power down state, this control voltage can be closed this transistor, and when this high-definition multimedia interface arrangement was power opening state, this control voltage can be opened this transistor.

2. high-definition multimedia interface arrangement as claimed in claim 1 is characterized in that: this transistorized this control end is coupled to a power supply of this high-definition multimedia interface arrangement.

3. high-definition multimedia interface arrangement as claimed in claim 1 is characterized in that: this leakage current protection circuit is arranged in the control chip of this high-definition multimedia interface arrangement.

4. high-definition multimedia interface arrangement as claimed in claim 1 is characterized in that: an electrostatic storage deflection (ESD) protection circuit in parallel with this resistance element is not set.

5. the control chip of a high-definition multimedia interface arrangement is characterized in that comprising:

One leakage current protection circuit includes:

One transistor includes a control end, one first end and one second end, and wherein, this control end is used to receive a control voltage, and this first end is coupled to a consumer electronics control port of this high-definition multimedia interface arrangement; And

One resistance element includes one first end and one second end, and wherein, this of this resistance element first end is used to receive a predetermined voltage level, and this second end of this resistance element is coupled to this transistorized this second end;

Wherein, when this high-definition multimedia interface arrangement was power down state, this control voltage can be closed this transistor, and when this high-definition multimedia interface arrangement was power opening state, this control voltage can be opened this transistor.

6. control chip as claimed in claim 5 is characterized in that: this transistorized this control end is coupled to a power supply of this high-definition multimedia interface arrangement.

7. control chip as claimed in claim 5 is characterized in that: an electrostatic storage deflection (ESD) protection circuit in parallel with this resistance element is not set.

Images