CN208046769U - HDMI-CEC circuits and HDMI-CEC equipment - Google Patents

Abstract

The utility model discloses a kind of HDMI-CEC circuits and HDMI-CEC equipment, wherein HDMI-CEC circuits include HDMI chips, MCU chip, the ports HDMI, isolation circuit and power circuit；The first end of the ports HDMI and the signal output end of external equipment connect, the second end of the ports HDMI is connect with HDMI chips, the second end of the ports HDMI is also connect through isolation circuit with MCU chip, and power circuit is connect with the second end of the power input of MCU chip, the power input of HDMI chips and the ports HDMI respectively.Technical solutions of the utility model can solve the problems, such as to cannot be satisfied CEC bus leakage current requirements when realizing CEC functions using MCU chip.

Description

HDMI-CEC circuits and HDMI-CEC equipment

Technical field

The utility model is related to HDMI-CEC technical fields, more particularly to a kind of HDMI-CEC circuits and HDMI-CEC are set It is standby.

Background technology

The equipment of band HDMI (High Definition Multimedia Interface, high-definition multimedia interface) In, CEC (Consumer Electronics Control, consumer electronics control) bus functionality is generally all carried, is significantly facilitated Mutual coordinated signals of the user in each equipment room.Although most HDMI chips can support CEC functions, works as and need to consider When meeting stand-by power consumption requirement, since HDMI chips cannot be satisfied the requirement of low-power consumption, so generally by HDMI cores when standby The power supply of piece is closed, and is needed to realize CEC functions at this time, is only simulated CEC functions with MCU chip, another situation is small part HDMI chips also need to simulate CEC functions using MCU chip without CEC functions.But since MCU chip is not specially to use The chip of CEC functions is done, more CEC hardware specification is not necessarily supported.

As shown in Figure 1, in existing HDMI-CEC circuits, closed in power supply, at this point, equipment is interfered in order to prevent Other equipment in CEC buses, CEC bus leakage currents need to be less than 1.8uA under off-mode, and in CEC general lines plus When pull-up circuit, V (CEC_IN) voltage range should be in predetermined voltage range.But MCU chip is in no electricity, CEC_IN State is uncertain, may be equivalent to the load that leakage current is 100uA, it is also possible to be equivalent to R33=100K Ω.When it is equivalent to When 100uA, it has been unsatisfactory for<The requirement of 1.8uA, when being equivalent to R33=100K, external test circuitry adds resistance on 27k to arrive 3.3V, at this time V (CEC_IN) be less than predeterminated voltage, be equally unsatisfactory for CEC voltage requests.Therefore MCU chip cannot achieve CEC work( Energy.

Utility model content

The main purpose of the utility model is to provide a kind of HDMI-CEC circuits, it is intended to solve to realize using MCU chip The problem of cannot be satisfied CEC bus leakage current requirements when CEC functions.

To achieve the above object, the utility model proposes a kind of HDMI-CEC circuits, which includes HDMI chips, MCU chip, the ports HDMI, isolation circuit and power circuit；The first ends of the ports HDMI and external equipment Signal output end connects, and the second end of the ports HDMI is connect with the HDMI chips, and the second end of the ports HDMI is also Connect with the MCU chip through the isolation circuit, the power circuit respectively with the power input of the MCU chip, institute State the power input connection of HDMI chips and the second end connection of the ports HDMI；Wherein,

The ports HDMI are used for when the power circuit is closed, external pull-up circuit to predeterminated voltage；And When the HDMI chips are standby, by the CEC orders received via the isolation circuit be sent to the MCU chip and via The isolation circuit receives the response signal of the MCU chip feedback；And in normal work, the CEC orders that will receive It is sent to the HDMI chips or is sent to the MCU chip via the isolation circuit, and receive the HDMI chips feedback Response signal or the response signal of MCU chip feedback is received via the isolation circuit；The HDMI chips are used for It is remained off when standby, and in normal work, is confirmed whether to receive the CEC orders simultaneously according to HDMI chip types Output response signal；The isolation circuit, it is standby for ending when the power circuit is closed, and in the HDMI chips When and normal work when be connected；The MCU chip, for being received via the isolation circuit when the HDMI chips are standby CEC orders and feedback response signal；And when normal work, it is confirmed whether to receive the CEC orders according to HDMI chip types And output response signal；The power circuit, for providing supply voltage for the HDMI chips and the MCU chip.

Preferably, the predeterminated voltage is more than or equal to 2.88V and is less than or equal to 3.63V.

Preferably, the power circuit includes first power source unit, second power source unit, third power supply unit and the first work Make voltage input end；Wherein, the power input of the first power source unit, the second power source unit power input and The power input of the third power supply unit is connect with the first operating voltage input terminal, the first power source unit Power output end is connect with the power input of the MCU chip, the power output end of the third power supply unit with it is described The power input of HDMI chips connects, and the power output end of the second power source unit is connect with the second end of the ports HDMI.

Preferably, the first power source unit includes first resistor and the first capacitance；Wherein, the first of the first resistor End, first capacitance first end connect with the first operating voltage input terminal, the second end of first capacitance is grounded, The second end of the first resistor is the power output end of the first power source unit.

Preferably, the second power source unit includes second resistance, the second capacitance and the first diode；Wherein, described The first end of two resistance, the first end of second capacitance are connect with the first operating voltage input terminal, second capacitance Second end ground connection, the second end of the second resistance connect with the anode of first diode, first diode Cathode is the power output end of the second power source unit.

Preferably, the isolation circuit includes the second diode, 3rd resistor, the 4th resistance, the 5th resistance and the one or three Pole pipe；Wherein, the anode of second diode is the second signal end of the isolation circuit, the moon of second diode The collector of pole, the first end of the 5th resistance and first triode interconnects, and the second end of the 5th resistance is institute The first signal end of isolation circuit is stated, the second end of the 5th resistance is connect with the second end of the ports HDMI, and described The first end of three resistance is the third signal end of the isolation circuit, the first end of the 3rd resistor and the MCU chip Signal output end connect, the second end of the 3rd resistor, the first end of the 4th resistance and first triode base Pole interconnects, and the second end of the 4th resistance and the emitter of first triode are grounded.

The utility model also proposes a kind of HDMI-CEC equipment, including HDMI-CEC circuits as described above, wherein described HDMI-CEC circuits include MCU chip, the ports HDMI, isolation circuit and power circuit；The first end of the ports HDMI It is connect with the signal output end of external equipment, the second end of the ports HDMI is connect with the HDMI chips, the ends HDMI Mouthful second end also connect with the MCU chip through the isolation circuit, the power circuit electricity with the MCU chip respectively The second end of source input terminal, the power input of the HDMI chips and the ports HDMI connects；Wherein,

The ports HDMI are used for when the power circuit is closed, external pull-up circuit to predeterminated voltage；And institute State HDMI chips it is standby when, the CEC orders received via the isolation circuit are sent to the MCU chip and via institute State the response signal that isolation circuit receives the MCU chip feedback；And in normal work, the CEC orders received are sent out It send to the HDMI chips or is sent to the MCU chip via the isolation circuit, and receive the HDMI chips feedback Response signal or the response signal that the MCU chip feedback is received via the isolation circuit；The HDMI chips, for waiting for It is remained off when machine, and in normal work, is confirmed whether to receive CEC orders and defeated according to HDMI chip types Go out response signal；The isolation circuit, for ending when the power circuit is closed, and the HDMI chips it is standby and It is connected when normal work；The MCU chip, for receiving CEC lives via the isolation circuit when the HDMI chips are standby Enable simultaneously feedback response signal；And when normal work, it is confirmed whether to receive the CEC orders and exports according to HDMI chip types Response signal；The power circuit, for providing supply voltage for the HDMI chips and the MCU chip.

Technical solutions of the utility model are formed by using MCU chip, the ports HDMI, isolation circuit and power circuit HDMI-CEC circuits.

When work, when HDMI chips type carry CEC functions, when power circuit is closed, in external test tools Whether CEC bus voltages are pulled to predeterminated voltage by pull-up circuit, full to test leakage current and CEC bus voltages in CEC buses Sufficient HDMI certifications need the requirement met, and isolation circuit is ended at this time, therefore, leakage current in CEC buses, and also, electricity is isolated The voltage of the output end on road is equal to the predeterminated voltage of pull-up circuit, thus when power circuit is closed, the HDMI-CEC circuits CEC buses do not interfere with other equipment normal work, and when HDMI chips are standby, HDMI chips do not work, and external equipment passes through The ports HDMI send CEC orders, and isolation circuit is connected at this time, and MCU chip detects normal CEC orders, and export response letter It number is replied, to which MCU chip simulated implementation CEC functions, when equipment works normally, external equipment can be utilized when standby CEC orders are sent by the ports HDMI, HDMI chips detect normal CEC orders, and output response signal is replied, real The CEC communications of existing monobus.

When HDMI chips are without CEC functions, when equipment works normally, external equipment sends CEC by the ports HDMI It orders, isolation circuit is connected at this time, and HDMI chips do not work, and MCU chip detects normal CEC orders, and exports response letter It number is replied.Technical solutions of the utility model can be realized using MCU chip simulated implementation CEC functions, to solve in profit The problem of CEC bus leakage current requirements being cannot be satisfied when realizing CEC functions with MCU chip.

Description of the drawings

In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only It is some embodiments of the utility model, for those of ordinary skill in the art, in the premise not made the creative labor Under, the structure that can also be shown according to these attached drawings obtains other attached drawings.

Fig. 1 is the electrical block diagram of prior art HDMI-CEC circuits；

Fig. 2 is the high-level schematic functional block diagram of one embodiment of the utility model HDMI-CEC circuits；

Fig. 3 is the high-level schematic functional block diagram of another embodiment of the utility model HDMI-CEC circuits；

Fig. 4 is the electrical block diagram of one embodiment of the utility model HDMI-CEC circuits.

The embodiments will be further described with reference to the accompanying drawings for the realization, functional characteristics and advantage of the utility model aim.

Specific implementation mode

The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model Clearly and completely describing, it is clear that described embodiment is only a part of the embodiment of the utility model, rather than all Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are not making creative work premise Lower obtained every other embodiment, shall fall within the protection scope of the present invention.

It is to be appreciated that the description for being related to " first ", " second " etc. in the present invention is used for description purposes only, and cannot It is interpreted as indicating or implying its relative importance or implicitly indicates the quantity of indicated technical characteristic.Define as a result, " the One ", the feature of " second " can explicitly or implicitly include at least one of the features.In addition, the skill between each embodiment Art scheme can be combined with each other, but must can be implemented as basis with those of ordinary skill in the art, when technical solution It will be understood that the combination of this technical solution is not present in conjunction with there is conflicting or cannot achieve when, also not in the utility model It is required that protection domain within.

The utility model proposes a kind of HDMI-CEC circuits.

It is the high-level schematic functional block diagram of one embodiment of the utility model HDMI-CEC circuits, the present embodiment with reference to Fig. 2, Fig. 2 In, which includes HDMI chips 10, the ports HDMI 20, MCU chip 30, isolation circuit 40 and power circuit 50.

Specifically, the first end of the ports HDMI 20 is connect with the signal output end of external equipment 300, and the of the ports HDMI 20 Two ends are connect with HDMI chips 10, and the second end of the ports HDMI 20 is also connect through isolation circuit 40 with MCU chip 30, power circuit 50 connect with the power input of the power input of MCU chip 30, HDMI chips 10 and the second end of the ports HDMI 20 respectively Connection.

The ports HDMI 20 are used for when power circuit 50 is closed, external pull-up circuit 200 to predeterminated voltage；And When HDMI chips 10 are standby, by the CEC orders received via isolation circuit 40 be sent to MCU chip 30 and via isolation electricity Road 40 receives the response signal that MCU chip 30 is fed back；And in normal work, the CEC orders received are sent to HDMI Chip 10 is sent to MCU chip 30 via isolation circuit 40, and receive HDMI chips 10 feedback response signal or via every The response signal that MCU chip 30 is fed back is received from circuit 40.

It should be noted that in the present embodiment, in order to not influence the linkage of other equipment, when power circuit 50 is closed, The ports HDMI 20 of this equipment are used as CEC buses, CEC bus voltages and CEC bus leakage currents to need to meet specification, because This is needed when power circuit 50 is closed plus puller circuit 200 to predeterminated voltage in the CEC buses of the ports HDMI 20, to survey Whether CEC buses leakage current and CEC bus voltages meet the requirements when examination MCU chip realizes CEC functions.

It should be noted that when HDMI chips 10 are standby, 10 unpowered voltage of HDMI chips remains off, this When in order to realize that CEC functions, the CEC orders of external equipment 300 are sent to MCU chip 30 by the ports HDMI 20, and normal When work, when HDMI chips 10 carry CEC functions, the CEC orders of external equipment 300 are sent to HDMI by the ports HDMI 20 Chip 10, when HDMI chips 10 are without CEC functions, the CEC orders of external equipment 300 are sent to by the ports HDMI 20 MCU chip 30, to utilize 30 simulated implementation CEC functions of MCU chip.

HDMI chips 10, for being remained off when standby, and in normal work, according to 10 class of HDMI chips Type is confirmed whether to receive the CEC orders and output response signal.

It should be noted that according to the characteristic of HDMI chips, when HDMI chips 10 are standby, HDMI chips 10 unpowered electricity Pressure, remains off, at this point, in order to realize CEC functions, can only exist simultaneously small part by 30 simulated implementation of MCU chip HDMI equipment in without CEC functions, so normal work when, when HDMI chips 10 carry CEC functions when, HDMI chips 10 then need according to the CEC orders and feedback response signal that receive in CEC buses when HDMI chips 10 are without CEC functions Pass through 30 simulated implementation CEC functions of MCU chip.

Isolation circuit 40, for ending when power circuit 50 is closed, and when HDMI chips 10 are standby and normal work Conducting when making.

It should be noted that in 50 unpowered voltage output of power circuit, in order to ensure the leakage current and electricity of CEC buses Pressure meets the requirements, 20 external pull-up circuit 200 of the ports HDMI to predeterminated voltage, at this point, isolation circuit 40 needs to keep cut-off shape State could realize that the leakage current of CEC buses and voltage meet the requirements, and HDMI chips 10 it is standby or normal work need profit When realizing CEC functions with MCU chip 30, isolation circuit 40 must tend to remain on, to realize MCU chip 30 and external equipment 300 carry out the detection and communication of CEC signals.

MCU chip 30, for receiving CEC orders and feedback response letter via isolation circuit 40 when HDMI chips 10 are standby Number；And when normal work, it is confirmed whether to receive the CEC orders and output response signal according to 10 type of HDMI chips.

It should be noted that when HDMI chips 10 carry CEC functions, MCU chip 30 is in 10 standby mode of HDMI chips Lower progress simulated implementation CEC functions realize CEC functions in normal work without work, HDMI chips 10.

When HDMI chips 10 are without CEC functions, then mould is kept when HDMI chips 10 are standby and when working normally The work of quasi- CEC functions.

Power circuit 50, for providing supply voltage for HDMI chips 10 and MCU chip 30.

It should be noted that when power circuit 50 powers off, the equal unpowered electricity of three power output ends of power circuit 50 Pressure output, when HDMI chips 10 are standby, the input of 10 non-transformer of HDMI chips, i.e., HDMI chips 10 do not work.

Technical solutions of the utility model are by using HDMI chips 10, MCU chip 30, the ports HDMI 20, isolation circuit 40 And power circuit 50 forms HDMI-CEC circuits.

When work, when HDMI chips 10 are with CEC functions and when power circuit 50 is closed, external pull-up circuit 200 will CEC bus voltages are pulled to predeterminated voltage, to test whether leakage current and CEC bus voltages in CEC buses meet HDMI certifications The requirement met, isolation circuit 40 is needed to end, therefore, leakage current in CEC buses, also, the output end of isolation circuit 40 Voltage be equal to the predeterminated voltage in pull-up circuit 200, to when power circuit 50 is closed, the CEC of the HDMI-CEC circuits Bus does not interfere with other equipment normal work, and when HDMI chips 10 are standby, HDMI chips 10 do not work, external equipment 300 CEC orders are sent by the ports HDMI 20, isolation circuit 40 is connected at this time, and MCU chip 30 detects normal CEC orders, and Output response signal is replied, to utilize 30 simulated implementation CEC functions of MCU chip when standby, in the normal work of equipment When making, external equipment 300 sends CEC orders by the ports HDMI 20, and HDMI chips 10 detect normal CEC orders, and defeated Go out response signal to be replied, realizes the CEC communications of monobus.

When HDMI chips 10 are without CEC functions, in normal work, external equipment 300 is sent by the ports HDMI 20 CEC orders, at this time isolation circuit 40 be connected, HDMI chips 10 do not work, and MCU chip 30 detects normal CEC orders, and defeated Go out response signal to be replied.Technical solutions of the utility model can realize using 30 simulated implementation CEC functions of MCU chip, to It solves the problems, such as to cannot be satisfied CEC bus leakage current requirements when realizing CEC functions using MCU chip.

Further, in the present embodiment, the predeterminated voltage is more than or equal to 2.88V and is less than or equal to 3.63V.

It should be noted that in the present embodiment, in order to make HDMI chips 10 meet the requirement of low-power consumption, under ideal case Generally the power supply of HDMI chips 10 is closed, according to HDMI code requirements, in the case where power circuit 50 is closed, in order to prevent CEC bus leakage currents interfere the CEC buses of other equipment, need to arrive plus puller circuit 200 in the CEC buses of the ports HDMI 20 3.3V, at this point, CEC reference voltage bus is needed in 2.88V between 3.63V, CEC is total when meeting the shutdown of HDMI-CEC circuits The voltage request of line.

Fig. 3 is the high-level schematic functional block diagram of another embodiment of the utility model HDMI-CEC circuits, together with reference to Fig. 2 and figure 3, in the present embodiment, power circuit 50 includes first power source unit 51, second power source unit 52, third power supply unit 53 and first Operating voltage input terminal.

Specifically, the power input of first power source unit 51, the power input of second power source unit 52 and third electricity The power input of source unit 53 is connect with the first operating voltage input terminal, the power output end of first power source unit 51 It is connect with the power input of MCU chip 30, the power input of the power output end and HDMI chips 10 of second power source unit 52 End connection, the power output end of third power supply unit 53 are connect with the second end of the ports HDMI.

It should be noted that first power source unit 51 is used to provide supply voltage, third power supply unit 53 for MCU chip 30 For being HDMI chips 10 for supply voltage, in the present embodiment, the first operating voltage size is 3.3V, is closed in power circuit 50 When, first power source unit 51, second power source unit 52 and the output of 53 equal non-transformer of third power supply unit are standby in HDMI chips 10 When, the output DC power supply of first power source unit 51 to MCU chip 30, the second DC power supply output DC power supply to CEC buses, the Three power supply units, 53 non-transformer exports, when HDMI-CEC circuits work normally, first power source unit 51 and third power supply unit 53 be respectively that MCU chip 30 and HDMI chips 20 provide supply voltage.

Fig. 4 is the electrical block diagram of one embodiment of the utility model HDMI-CEC circuits, in the present embodiment, the first electricity Source unit 51 includes first resistor R1 and the first capacitance C1.

Specifically, the first end of first resistor R1, the first end of the first capacitance C1 and the first operating voltage input terminal Connection, the second end ground connection of the first capacitance C1, the second end of first resistor R1 is the power output end of first power source unit 51.

In the present embodiment, the first capacitance C1 is used to be filtered, and prevents harmonic wave from entering in MCU chip 30 and causes false triggering, First resistor R1 is for being depressured current limliting.

Preferably, second power source unit 52 includes second resistance R2, the second capacitance C2 and the first diode D1.

Specifically, the first end of second resistance R2, the first end of the second capacitance C2 and the first operating voltage input terminal Connection, the second end ground connection of the second capacitance C2, the second end of second resistance R2 are connect with the anode of the first diode D1, and the one or two The cathode of pole pipe D1 is the power output end of second power source unit 52.

In the present embodiment, the second capacitance C2 prevents harmonic wave from entering CEC buses and causes to cause signal dry for being filtered It disturbs, second resistance R2 is for being depressured current limliting, and the first diode D1 when the first operating voltage input terminal voltage is zero for being isolated The leakage current of first power source unit 51.

Preferably, isolation circuit 40 includes the second diode D2,3rd resistor R3, the 5th resistance R5 of the 4th resistance R4 and the One triode Q1.

The anode of second diode D2 is the second signal end of isolation circuit 40, the cathode of the second diode D2, the 5th electricity The first end of R5 and the collector interconnection of the first triode Q1 are hindered, the second end of the 5th resistance R5 is the first letter of isolation circuit 40 Number end, the second end of the 5th resistance R5 connect with the second end of the ports HDMI 20, and the first end of 3rd resistor R3 is isolation circuit The first end of 40 third signal end, 3rd resistor R3 is connect with the signal output end of MCU chip 30, and the second of 3rd resistor R3 The base stage interconnection at end, the first end of the 4th resistance R4 and the first triode Q1, the second end and the first triode of the 4th resistance R4 The emitter of Q1 is grounded.

In the present embodiment, when power circuit 50 is closed, the voltage of the first operating voltage input terminal is equivalent to 0V, according to One diode D1 forward conductions, the characteristic reversely ended, 52 leakage current of second power source unit flow into CEC buses, at this time MCU core The state of 30 unpowered power supply of piece, MCU chip 30 is uncertain, and MCU chip 30 may be equivalent to the leakage current close to 100uA, or Person is equivalent to the load of 100K Ω, when it is equivalent to 100uA, the first of the output end MCU_CEC_OUT controls of MCU chip 30 The base stage of triode Q1 is low level, and the first triode Q1 cut-offs, therefore, leakage current in CEC buses leaks in CEC buses Electric current is less than 1.8uA, meets the requirement of CEC bus leakage currents, and when MCU chip 30 is equivalent to 100K Ω, pull-up circuit 200 will Voltage is pulled to predeterminated voltage, at this point, due to the buffer action of the second diode D2, for MCU chip 30 without partial pressure, CEC is total Line voltage is equal to predeterminated voltage, meets the voltage request of CEC buses, therefore, when power circuit 50 is closed, isolation circuit 40 rises The effect of isolation leakage current and voltage is arrived.

When HDMI chips 10 are standby, the input of third DC power supply 53 (not shown) non-transformer, the not work of HDMI chips 10 Make, external equipment 300 sends CEC orders by the ports HDMI 20, when the CEC_IN signals for being input to isolation circuit 40 are low electricity Usually, due to the effect of the second diode D2, clamped MCU_CEC_IN terminal voltages in 0.5V or so, 0.5V are the pressure of diode It drops, MCU chip 30 detects that CEC orders are low level at this time, when CEC_IN signals are high level 3.3V, also due to second The presence of diode D2, when MCU chip 30 is equivalent to 100uA, the signal input part MCU_CEC_IN of MCU chip 30 at this time The high-level input voltage of voltage V (MCU_CEC_IN)=3.3V-100uA*R1, MCU chip 30 are 0.7*3.3V=2.31V, In the present embodiment, first resistor R1 is smaller, and voltage V (MCU_CEC_IN) is more than the high-level input voltage of MCU chip 30, when When MCU chip 30 is equivalent to 100K Ω, voltage V (MCU_CEC_IN)=3.3V*100/ (R1+100K Ω), voltage V (MCU_ CEC_IN) also greater than the high level input terminal voltage of MCU chip 30, therefore, in HDMI chips 10, isolation circuit 40 is realized The conversion of CEC signal levels be isolated, MCU chip 30 can detect that normal CEC orders, MCU chip 30 receive CEC It after order, is replied by MCU_CEC_OUT output end output response signals, realizes the CEC communications of monobus.

When HDMI-CEC circuits work normally, if HDMI chips 10 carry CEC functions at this time, external equipment The 300 CEC orders sent are directly sent to HDMI chips 10 by the ports HDMI 20, and HDMI chips 10 are carried out according to CEC orders Response is replied, and when HDMI chips 10 are without CEC functions, then the CEC orders that external equipment 300 is sent pass through the ports HDMI 20 And isolation circuit 40 is sent to MCU chip 30, MCU chip 30 carries out response reply according to CEC orders, realizes CEC functions.

Together with reference to Fig. 2 and Fig. 4, the operation principle of the present embodiment HDMI-CEC circuits is described in detail below：

In the present embodiment, which includes HDMI chips 10, the ports HDMI 20, MCU chip 30, isolation circuit 40 and power circuit 50, the first end of the ports HDMI 20 connect with the signal output end of external equipment 300, the of the ports HDMI 20 Two ends are connect with HDMI chips 10, and the second end of the ports HDMI 20 is also connect through isolation circuit 40 with MCU chip 30, power circuit 50 connect with the power input of the power input of MCU chip 30, HDMI chips 10 and the second end of the ports HDMI 20 respectively Connection.

When work, when power circuit 50 powers off, 50 unpowered voltage output of power circuit, according to the two of MCU chip 30 Kind equivalent situation, when it is equivalent to the load of 100uA, MCU_CEC_OUT output ends are low level, and the first triode Q1 is cut Only, simultaneously as the presence of the first diode D1 and the second diode D2, leakage current is zero in CEC buses, and it is total to meet CEC Line current needs to be less than the requirement of 1.8uA under ideal case, and when MCU chip 30 is equivalent to 100K Ω, pull-up circuit 200 will CEC bus voltages are pulled to 3.3V, and due to the buffer action of the second diode D2, MCU chip 30 is without partial pressure, voltage V (CEC_IN) voltage is equal to 3.3V, meets requirement of the CEC bus voltages in 2.88~3.63 ranges, in power circuit 50 In the case of closing, solve the problems, such as that the voltage and leakage current in CEC buses are unsatisfactory for CEC bus requests, to realize profit With the purpose of 30 simulated implementation CEC functions of MCU chip.

When HDMI chips 10 are standby, first power source unit 51 is that MCU chip 30 provides supply voltage, third power supply unit 53 unpowered voltage outputs, HDMI chips 10 do not work, and external equipment 300 is total to CEC by the transmission CEC orders of the ports HDMI 20 On line, when CEC orders are low level, the ends MCU_CEC_IN of MCU chip 30 detect low level, when CEC orders are high electricity Usually, the ends MCU_CEC_IN of MCU chip 30 detect that high level, MCU chip 30 are started to work, and according to the CEC received Order is fed back, and by MCU_CEC_OUT output end output response signals, the first triode Q1 conductings, response signal passes through The output of the ports HDMI 20 is realized to external equipment 300 to link, to realize the CEC communications of monobus.

When HDMI-CEC circuits work normally, the case where whether carrying CEC functions according to HDMI chips 10, carries out different The processing of signal, when HDMI chips 10 carry CEC functions, CEC orders are sent to HDMI chips 10 by the ports HDMI 20, with The detection and response for carrying out signal, realize the communication of monobus, when HDMI chips 10 are without CEC functions, CEC orders pass through The ports HDMI 20 and isolation circuit 40 are sent to MCU chip 30, and MCU chip 30 carries out response reply according to CEC orders, and simulation is real Existing CEC functions.Therefore, even if partial HDMI chips 10 are without CEC functions, 30 simulated implementation of MCU chip can equally be utilized CEC functions.

The utility model also proposes a kind of HDMI-CEC equipment, including HDMI-CEC circuits as described above, the HDMI- CEC equipment includes concrete structure reference above-described embodiment of HDMI-CEC circuits as described above, due to this HDMI-CEC equipment Use whole technical solutions of above-mentioned all embodiments, therefore at least institute caused by the technical solution with above-described embodiment There is advantageous effect, this is no longer going to repeat them.

The above is only the preferred embodiment of the present invention, and it does not limit the scope of the patent of the present invention, It is every under the inventive concept of the utility model, equivalent structure made based on the specification and figures of the utility model becomes It changes, or directly/be used in other related technical areas indirectly and be included in the scope of patent protection of the utility model.

Claims (7)

1. a kind of HDMI-CEC circuits, which is characterized in that including HDMI chips, MCU chip, the ports HDMI, isolation circuit and electricity Source circuit；The signal output end of the first ends of the ports HDMI and external equipment connects, the second end of the ports HDMI with The HDMI chips connection, the second end of the ports HDMI are also connect through the isolation circuit with the MCU chip, the electricity Source circuit respectively with the power input of the MCU chip, the power input of the HDMI chips and the ports HDMI Second end connects；Wherein,

The ports HDMI are used for when the power circuit is closed, external pull-up circuit to predeterminated voltage；And described When HDMI chips are standby, the CEC orders received via the isolation circuit are sent to the MCU chip and via described Isolation circuit receives the response signal of the MCU chip feedback；And in normal work, the CEC orders received are sent To the HDMI chips or it is sent to the MCU chip via the isolation circuit, and receives the sound of the HDMI chips feedback Induction signal or the response signal that the MCU chip feedback is received via the isolation circuit；

The HDMI chips, it is true according to HDMI chip types for being remained off when standby, and in normal work Recognize and whether receives the CEC orders and output response signal；

The isolation circuit, for ending when the power circuit is closed, and the HDMI chips are standby and normal work Conducting when making；

The MCU chip, for receiving CEC orders and feedback response via the isolation circuit when the HDMI chips are standby Signal；And when normal work, it is confirmed whether to receive the CEC orders and output response signal according to HDMI chip types；

The power circuit, for providing supply voltage for the HDMI chips and the MCU chip.

2. HDMI-CEC circuits as described in claim 1, which is characterized in that the predeterminated voltage is more than or equal to 2.88V And it is less than or equal to 3.63V.

3. HDMI-CEC circuits as described in claim 1, which is characterized in that the power circuit include first power source unit, Second power source unit, third power supply unit and the first operating voltage input terminal；Wherein,

The power input of the first power source unit, the power input of the second power source unit and the third power supply list The power input of member is connect with the first operating voltage input terminal, the power output end of the first power source unit and institute The power input connection of MCU chip is stated, the power output end of the third power supply unit and the power supply of the HDMI chips are defeated Enter end connection, the power output end of the second power source unit is connect with the second end of the ports HDMI.

4. HDMI-CEC circuits as claimed in claim 3, which is characterized in that the first power source unit include first resistor and First capacitance；Wherein,

The first end of the first resistor, the first end of first capacitance are connect with the first operating voltage input terminal, institute The second end ground connection of the first capacitance is stated, the second end of the first resistor is the power output end of the first power source unit.

5. HDMI-CEC circuits as claimed in claim 3, which is characterized in that the second power source unit include second resistance, Second capacitance and the first diode；Wherein,

The first end of the second resistance, the first end of second capacitance are connect with the first operating voltage input terminal, institute The second end ground connection of the second capacitance is stated, the second end of the second resistance connect with the anode of first diode, and described the The cathode of one diode is the power output end of the second power source unit.

6. HDMI-CEC circuits as described in claim 1, which is characterized in that the isolation circuit includes the second diode, the Three resistance, the 4th resistance, the 5th resistance and the first triode；Wherein,

The anode anode of second diode is the second signal end of the isolation circuit, and the cathode of second diode is cloudy The collector of pole, the first end of the 5th resistance and first triode interconnects, and the second end of the 5th resistance is institute The first signal end of isolation circuit is stated, the second end of the 5th resistance is connect with the second end of the ports HDMI, and described The first end of three resistance is the third signal end of the isolation circuit, the first end of the 3rd resistor and the MCU chip Signal output end connect, the second end of the 3rd resistor, the first end of the 4th resistance and first triode base Pole interconnects, and the second end of the 4th resistance and the emitter of first triode are grounded.

7. a kind of HDMI-CEC equipment, which is characterized in that include the HDMI-CEC electricity as described in claim 1 to 6 any one Road.