CN104883168B

CN104883168B - It can prevent electric current from pouring in down a chimney to the integrated circuit of power line

Info

Publication number: CN104883168B
Application number: CN201410069483.0A
Authority: CN
Inventors: 高硕廷; 叶俊文
Original assignee: MStar Semiconductor Inc Taiwan
Current assignee: MediaTek Inc
Priority date: 2014-02-27
Filing date: 2014-02-27
Publication date: 2017-12-15
Anticipated expiration: 2034-02-27
Also published as: CN104883168A

Abstract

The present invention, which is provided with, a kind of prevents electric current from pouring in down a chimney to the integrated circuit of a power line.The integrated circuit includes an input circuit, and it draws high circuit with a joint sheet and one.This, which is drawn high circuit and included, draws high switch, a body end controlling switch and a control circuit.This, which draws high switch, has one first control terminal and one first body end, to electrically connect the joint sheet to the power line.The body end controlling switch has one second control terminal and one second body end, to connect first body end and second body end to the power line.The control circuit is electrically connected to the power line and the joint sheet, according to an engagement pad voltage of an internal signal, a supply voltage of the power line and the joint sheet, come control this first with second control terminal.When the supply voltage is a predeterminated voltage, the control circuit makes the body end controlling switch be a conducting state.When the supply voltage is a ground voltage, and the engagement pad voltage is the predeterminated voltage, it is a closed mode that the control circuit, which controls the body end controlling switch to draw high switch with this,.

Description

It can prevent electric current from pouring in down a chimney to the integrated circuit of power line

Technical field

Input circuit of the relation of the present invention on integrated circuit, especially with respect to the input electricity that can prevent that electric current from pouring in down a chimney Road.

Background technology

Communication between electronic product, the transmission line and special communication specification that can pass through entity are reached.It is general and Speech, it is responsible for providing the integrated circuit of signal, can be described as signal source integrated circuit (source IC), and passes through transmission line and receive letter Number integrated circuit, receiving terminal integrated circuit (sink IC) can be referred to as.

Many communication specifications employ differential wave to communicate, and it can reach at a relatively high communication signal transmission speed. Simply, for high speed communication, receiving terminal integrated circuit generally requires to be collocated with terminal resistance, for reducing signal reflex, Increase transmission speed.For example, terminal resistance (terminator) can be located in receiving terminal integrated circuit, be connected to one and connect Close between pad and a power line.In normal signal transmission, the power line of signal source integrated circuit, and receiving terminal integrated circuit Power line, can common drive connection transmission line therein.

However, when the power-off of the electronic product where receiving terminal integrated circuit, receiving terminal integrated circuit in theory Power line, its supply voltage should drop to 0V as time go on.But in practice, the electricity of signal source integrated circuit Source line, the terminal resistance of transmission line and receiving terminal integrated circuit may be passed through, the power line of receiving terminal integrated circuit is poured in down a chimney Enter electric current, its voltage is more than 0V.The phenomenon that such electric current pours in down a chimney, in the electricity of the electronic installation where receiving terminal integrated circuit When source is reopened, some default value mistakes of receiving terminal integrated circuit may be caused.Therefore, the phenomenon that electric current pours in down a chimney is, it is necessary to be subject to Consider and prevent.

The content of the invention

Embodiment, which is provided with, a kind of prevents electric current from pouring in down a chimney to the integrated circuit of a power line.It is defeated that the integrated circuit includes one Enter circuit, it draws high circuit with a joint sheet and one.This draw high circuit include draw high switch, a body end control open Pass and a control circuit.This, which draws high switch, has one first control terminal and one first body end, to electrically connect the joint sheet To the power line.The body end controlling switch has one second control terminal and one second body end, to connect first body end with Second body end is to the power line.The control circuit is electrically connected to the power line and the joint sheet, according to an internal signal, the electricity One engagement pad voltage of one supply voltage of source line and the joint sheet, come control this first with second control terminal.When the electricity When source voltage is a predeterminated voltage, the control circuit makes the body end controlling switch be a conducting state.When the supply voltage is one Ground voltage, and when the engagement pad voltage is the predeterminated voltage, the control circuit controls the body end controlling switch to be drawn high out with this Pass is a closed mode.

Embodiment be separately provided with it is a kind of prevent electric current from pouring in down a chimney to the integrated circuit of a power line, it includes a static discharge Bus, multiple input circuits and bus connection circuit.Each input circuit includes a joint sheet and a static discharge Diode.The ESD diode is connected between the joint sheet and the static discharge bus.Bus connection circuit is electrically connected It is connected between the static discharge bus and the power line, it is a supply voltage according to the power line, several with such joint sheet Pad voltage is engaged to control the electric connection of the static discharge bus and the power line.

Brief description of the drawings

Fig. 1 shows two electronic installations 100 and 101 being connected with transmission line 112a with 112b.

Fig. 2 shows the solution in a kind of system, the generation that can prevent the electric current in Fig. 1 from pouring in down a chimney.

Receiving terminal integrated circuit 300 of Fig. 3 displays according to one embodiment of the invention.

Fig. 4 citings thin portion illustrates input circuit 302a.

Fig. 5 A show power line VCC supply voltage, when the engagement pad voltage with joint sheet pad_a is all 3.3V, in Fig. 4 MOS transistor on off state.

Fig. 5 B show that power line VCC supply voltage is 0V, when the engagement pad voltage with joint sheet pad_a is 3.3V, Fig. 4 In MOS transistor on off state.

Fig. 6 illustrates multiplexer 304a in Fig. 3 and 304b and is connected circuit 306.

Embodiment

Fig. 1 shows two electronic installations 100 and 101 being connected with transmission line 112a with 112b.There is letter in electronic installation 100 Number source integrated circuit 116, it can pass through transmission line 112a and 112b, send out the reception in differential wave to electronic installation 101 Hold integrated circuit 107.For example, electronic installation 100 is a multimedia player, and electronic installation 101 is a LCD TV, Transmission line 112a and 112b is then high-definition multimedia interface (high density multimedia interface, HDMI) Two transmission lines in cable.As illustrated, having terminal resistance 118a and 118b in signal source integrated circuit 116, it is electrically connected to One 3.3V power line.There are terminal resistance 114a and 114b in receiving terminal integrated circuit 107, be electrically connected to power line VCC.Eventually End resistance 114a and 114b, 118a and 118b are the impedances for matched transmission line 112a and 112b.During normal operating, power supply Line VCC supply voltage should be 3.3V.

Electronic installation 101 has a main power switch 102, and in an example, it can be the main power switch of a TV. When main power switch 102 turns on, low pressure difference linear voltage regulator (low dropout regulator, LDO) 106 by 5V electricity Source line VPP is powered, and provides power line VCC3.3V power supply.When main power switch 102 is breaking, power line VPP is expected should This is 0V (ground voltage).When main power switch 102 has just become conducting from open circuit, power sensor detecting circuit 104 ideally must The appearance of power line VPP voltage rising edge need be detected, then through end RST is reset, resets receiving terminal integrated circuit 107, the setting of some of which of logic circuit 108 is returned to default value.

Simply, as shown in Figure 1, when main power switch 102 closes (open circuit), although LDO106 is not to power line VCC powers, but power line VCC supply voltage, may be led because of the 3.3V power lines in signal source integrated circuit 116 The electric current of cause pours in down a chimney, and maintains 3.3V always.Although main power switch 102 is to close, 3.3V power line VCC, meeting Because LDO106 a little electric leakage, and make power line VPP voltage may not be expected 0V, and become 2V or so.Such as Fig. 1 Shown, reverse irrigated current I_REV can charge to power line VPP.Now, once main power switch 102 becomes to turn on from open circuit, originally Power line VPP voltage should be begun to ramp up to 5V from 0V, but begin to ramp up 5V by 2V due to LDO106 electric leakage, this is past It is past to cause power sensor detecting circuit 104 to detect less than rising edge, and receiving terminal integrated circuit 107 can not be reset.As a result it is exactly to cause Some settings are not replied as default value in logic circuit 108, and then it is not normal to operate electronic installation 101.

Fig. 2 shows the solution in a kind of system, the generation that can prevent electric current from pouring in down a chimney.One is added compared to Fig. 1, Fig. 2 Diode 202, it is a separation assembly (discrete device), is connected between power line VPP and LDO106.Diode 202 can block the reverse irrigated current I_REV from LDO106 toward power line VPP, it is possible to when making the closing of main power switch 102, Power line VPP voltage about maintains expected 0V.But add separation assembly, meaning add buying on burden, The cost in complexity and manufacture in production management.

Receiving terminal integrated circuit 300 of Fig. 3 displays according to one embodiment of the invention.For the convenience that solution is said, with In lower explanation, the receiving terminal integrated circuit 107 in Fig. 1 will be substituted with the receiving terminal integrated circuit 300 in Fig. 3, but the present invention The system architecture being not limited in Fig. 1, other system architectures can also be applied.

Receiving terminal integrated circuit 300 includes input circuit 302a and 302b, multiplexer 304a and 304b and is connected electricity Road 306.Input circuit 302a and 302b is electrically connected to transmission line 112a and 112b with joint sheet pad_a and pad_b respectively, uses The differential wave come is transmitted to receive from signal source integrated circuit 116, and signal source integrated circuit 116 can be prevented and pour in down a chimney electricity Flow to power line VCC.Multiplexer 304a and 304b and it is connected circuit 306 and can be considered as bus connection circuit, its framework comes A supply voltage according to power line VCC, the engagement pad voltage with joint sheet pad_a and pad_b, to control static discharge bus ESD_BUS and power line VCC electric connection.

Supply voltages of the multiplexer 304a according to power line VCC, selection ground wire one of GND or joint sheet pad_a, It is electrically connected to control terminal CTL_a.Similar, supply voltages of the multiplexer 304b according to power line VCC, selection ground wire GND Or one of joint sheet pad_b, it is electrically connected to control terminal CTL_b.According to control terminal CTL_a and CTL_b, circuit is connected Electric connection between 306 control static discharge bus ESD_BUS and power line VCC.

For two the transmission lines 112a and 112b that arrange in pairs or groups, receiving terminal integrated circuit 300 only lift two input circuit 302a with 302b is example, but in other embodiments of the invention, an integrated circuit can only have an input circuit, it is possibility to have two Input circuit more than individual.For example, the integrated circuit implemented according to the present invention has three input circuits, three multiplexings Device and a connection circuit.

Input circuit 302a and 302b circuit framework are substantially similar with operating.Input circuit 302a is will be described below, and Input circuit 302b is referred to input circuit 302a description and analogizes and learn, therefore is not repeated.

Input circuit 302a, which includes, draws high circuit 303a, ESD diode 305a and 307a and joint sheet pad_a。

3.3V can be drawn high joint sheet pad_a by drawing high circuit 303a.In circuit 303a is drawn high, PMOS312a and end End resistance 310a is serially connected between power line VCC and joint sheet pad_a.PMOS312a, which can be considered as, draws high switch, and it is to lead When logical, the bonding voltage on joint sheet pad_a can be drawn high.PMOS316a is with parasitizing the body diode in PMOS312a (body diode) 314a is then serially connected between terminal resistance 310a and power line VCC, to control PMOS312a body end (bulk) whether it is electrically connected to power line VCC, it is possible to be considered as a body end controlling switch.Control circuit 308a is according to power line VCC supply voltage, joint sheet pad_a engagement pad voltage and internal signal S_a, to control PMOS312a's and 316a Lock end.

ESD diode 305a provides joint sheet pad_a to a static discharge bus ESD_BUS static discharge road Footpath；ESD diode 307a then provides another electrostatic discharging paths of the joint sheet pad_a to ground wire GND.

Fig. 4 citings thin portion illustrates input circuit 302a.In order that Fig. 4 simplicity, although not drawing, input circuit All PMOS body end (bulk) is all electronically connected to floating end Flt in 302a.

PMOS402a in parallel and NMOS404a can be considered as a transmission circuit, can be used to transmit internal signal S_a to PMOS312a lock end.NMOS404a lock end is electrically connected to power line VCC.PMOS402a lock end is electrically connected to NMOS420a, and NMOS420a lock end is connected to ground wire GND.

Circuit between resistance 422a and PMOS312a lock end has PMOS406a and 410a and NMOS408a, Their lock end is all electronically connected to power line VCC.NMOS408a is connected in parallel with PMOS410a.From another perspective, PMOS406a and 410a is connected in series between resistance 422a and PMOS312a lock end.

Circuit between resistance 422a and ground wire GND has PMOS412a, 414a, 416a and NMOS418a. PMOS412a, 414a, 416a are sequentially serially connected between resistance 422a and ground wire GND.NMOS418a is connected to PMOS316a's Between lock end and ground wire GND.PMOS414a lock end is connected to PMOS402a lock end.PMOS412a, 416a and NMOS418a lock end, is all electronically connected to power line VCC.

Fig. 5 A show power line VCC supply voltage, when the engagement pad voltage with joint sheet pad_a is all 3.3V, in Fig. 4 MOS transistor on off state.The MOS transistor for having cross represents closing (being not turned on), the MOS transistor table not crossed Show conducting or a little conducting.It can be found that the NMOS418a of conducting makes PMOS316a maintain conducting state from Fig. 5 A, So floating end Flt, that is, in Fig. 4 all PMOS body end, be all electronically connected to power line VCC, be 3.3V.

Although for NMOS420a to close, it can provide a leakage path, pull down PMOS402a lock end a littlely. NMOS408a can make the voltage at PMOS402a lock end, not higher than the critical voltage (threshold that 3.3V subtracts NMOS408a voltage)Vtn.So PMOS402a can be a little conducting or complete conducting.Therefore, NMOS404a in parallel and conducting With PMOS402a, internal signal S_a can be made to arrive at PMOS312a lock end, switch PMOS312a.

Fig. 5 B show that power line VCC supply voltage is 0V, when the engagement pad voltage with joint sheet pad_a is 3.3V, Fig. 4 In MOS transistor on off state.The same, the MOS transistor for having cross represents to close (being not turned on), does not cross MOS transistor represents conducting or a little conducting.The PMOS410a of conducting make it that PMOS402a lock end is 3.3V.Close PMOS402a and NMOS404a has completely cut off PMOS312a lock end and internal signal S_a.Similar, the PMOS414a of closing Prevention PMOS316a is switched on.It can be found that the PMOS412a of conducting has been electrically connected with joint sheet pad_a and arrived in Fig. 5 B PMOS316a lock end, so closing PMOS316a.Similarly, the PMOS410a and 406a of conducting have electrically connected joint sheet pad_ A to PMOS312a lock end, so closing PMOS312a.Therefore, now supply voltage be 0V power line VCC safely with Engage that the joint sheet pad_a phases that pad voltage is 3.3V are electrically isolated, and power line VCC will not be poured into electric current, electric current pours in down a chimney can be by Prevention.In theory, the now big appointment of floating end Flt voltage is that 3.3V has minused the body diode parasitized in PMOS312a The value of the forward startup bias (forward voltage) of (314 in Fig. 3).

Fig. 6 illustrates multiplexer 304a in Fig. 3 and 304b and is connected circuit 306.In order that Fig. 6 simplicity, to the greatest extent Pipe is not drawn, and all PMOS shown body end (bulk) is all electronically connected to static discharge bus in Fig. 6 ESD_BUS。

By taking multiplexer 304a as an example, it has NMOS Na and PMOS Pa.When power line VCC supply voltage is 0V, NMOS Na are closed, PMOS Pa conductings, so multiplexer 304a electrically connects joint sheet pad_a to control terminal CTL_a.Opposite, When power line VCC supply voltage is 3.3V, NMOS Na conductings, PMOS Pa are closed, so multiplexer 304a connects Ground wire GND to control terminal CTL_a.

As can be seen from Figure 6, when power line VCC supply voltage is 3.3V, PMOS Pca and Pcb lock end are all 0V.Even Connect in circuit 306, the PMOS Pca and Pcb of series connection are conductings, so connection circuit 306 electrically connected power line VCC with it is quiet Discharge of electricity bus ESD_BUS.Now static discharge bus ESD_BUS is shorted to power line VCC, and voltage is about 3.3V.

When power line VCC supply voltage is 0V, as long as the engagement pad voltage for having any one joint sheet is 3.3V, even Meet the just electrically isolated power line VCC and static discharge bus ESD_BUS of circuit 306.Now, although static discharge bus ESD_ BUS may be because ESD diode 305a or 305b conducting, and its voltage may be pulled high to about 2.5V or so.But because The isolation effect that connection circuit 306 is provided, 2.5V static discharge bus ESD_BUS will not produce to 0V power line VCC The effect of charging.Joint sheet pad_a and pad_b pours in down a chimney the issuable electric current of power line VCC institutes, can be prevented.

As seen from the above description, when the receiving terminal integrated circuit 107 in Fig. 1 is with the institute of receiving terminal integrated circuit 300 in Fig. 3 Substitution, and when main power switch 102 is closed and (is not turned on), the event that electric current pours in down a chimney will not occur, power line VCC and VPP may be used To maintain 0V.Therefore, when main power switch 102 is opened and turned on, power sensor detecting circuit 104 can correctly detect power supply The appearance of line VPP voltage rising edge, and stably reset receiving terminal integrated circuit 107.

The foregoing is only presently preferred embodiments of the present invention, all equivalent changes done according to scope of the present invention patent with Modification, it should all belong to the covering scope of the present invention.

Claims

1. a kind of prevent electric current from pouring in down a chimney to the integrated circuit of power line, include：

Input circuit, include：

Joint sheet, to be electrically connected to external signal line；And

Circuit is drawn high, is included：

Switch is drawn high, it has the first control terminal and the first body end, to electrically connect the joint sheet to the power line；

Body end controlling switch, it has the second control terminal and the second body end, to connect first body end and second body end To the power line；And

Control circuit, is electrically connected to the power line and the joint sheet, according to internal signal, the power line supply voltage and The engagement pad voltage of the joint sheet, come control this first with second control terminal；

Wherein, when the supply voltage is predeterminated voltage, the control circuit makes the body end controlling switch be conducting state；And

When the supply voltage is ground voltage, and the engagement pad voltage is the predeterminated voltage, the control circuit controls the body end It is closed mode that controlling switch draws high switch with this.

2. integrated circuit as claimed in claim 1, it is characterised in that when the supply voltage is the predeterminated voltage, the control Circuit is according to the internal signal, to control this to draw high switch.

3. integrated circuit as claimed in claim 1, it is characterised in that when the supply voltage is the ground voltage, the control Circuit makes the joint sheet be electrically connected to first control terminal and second control terminal.

4. integrated circuit as claimed in claim 1, it is characterised in that the control circuit includes：

Transmission circuit, to transmit the internal signal to first control terminal, it includes：

The first NMOS and the first PMOS in parallel, the first NMOS and the first PMOS to transmit the internal signal to this One control terminal, the first NMOS lock end are electrically connected to the power line；

First circuit, it is connected between first control terminal and the joint sheet, includes：

2nd NMOS and the 2nd PMOS in parallel, the 2nd NMOS and the 2nd PMOS extremely should to electrically connect the joint sheet First PMOS lock end, the 2nd NMOS and the 2nd PMOS two lock ends are electrically connected to the power line；And

3rd PMOS, its lock end are electrically connected to the power line, to electrically connect first control terminal to the first PMOS lock End；And

Second circuit, it is electrically connected between second control terminal and the joint sheet, includes：

4th PMOS, the 5th PMOS and the 6th PMOS, it is series between the joint sheet and ground wire, the 4th and the 6th PMOS two lock ends are electrically connected to the power line, and the 5th PMOS lock end is connected to the first PMOS lock end；And

3rd NMOS, electrically connect second control terminal to the ground wire, its lock end and be electrically connected to the power line.

5. integrated circuit as claimed in claim 4, it is characterised in that each PMOS in the control circuit has body end, It is each coupled electrically to first body end.

6. integrated circuit as claimed in claim 4, it is characterised in that the control circuit has additionally comprised the 4th NMOS, electrical connection Between the first PMOS lock end and the ground wire, the 4th NMOS lock end is electrically connected to the ground wire.

7. integrated circuit as claimed in claim 1, it is characterised in that this is drawn high switch and is series at the joint sheet with first resistor Between the power line, the control circuit has second resistance, is electrically connected to the joint sheet, and the first resistor is outer to match this The impedance of portion's signal wire.

8. integrated circuit as claimed in claim 1, it is characterised in that the input circuit is the first input circuit, the integrated electricity Road has additionally comprised the second input circuit, and each input circuit is respectively provided with ESD diode, be connected to static discharge bus with Between corresponding pad, the integrated circuit has additionally comprised：

Bus connects circuit, is connected between the static discharge bus and the power line, according to the supply voltage, first input The engagement pad voltage of circuit and the engagement pad voltage of second input circuit, to control the static discharge bus with being somebody's turn to do Electric connection between power line.

9. a kind of prevent electric current from pouring in down a chimney to the integrated circuit of power line, include：

Static discharge bus；

Multiple input circuits, each input circuit include：

Joint sheet；And

ESD diode, it is connected between the joint sheet and the static discharge bus；And

Bus connects circuit, is electrically connected between the static discharge bus and the power line, the supply voltage according to the power line The electric connection of the static discharge bus and the power line is controlled with several engagement pad voltages of those joint sheets.

10. integrated circuit as claimed in claim 9, it is characterised in that when the supply voltage is predeterminated voltage, the power line It is electrically connected to the static discharge bus.

11. integrated circuit as claimed in claim 9, it is characterised in that bus connection circuit includes：

Circuit is connected, is connected between the static discharge bus and the power line；And

Multiple multiplexers, correspond to the plurality of input circuit respectively, each multiplexer respectively according to the supply voltage will be grounded with One of joint sheet of corresponding input circuit is electrically connected to the connection circuit.

12. integrated circuit as claimed in claim 11, it is characterised in that each multiplexer includes NMOS and PMOS, should NMOS is electrically connected between the connection circuit and the ground wire, and the PMOS is electrically connected to connection circuit input circuit corresponding with this The joint sheet between, the NMOS and the PMOS two lock ends are all electrically connected to the power line.

13. integrated circuit as claimed in claim 11, it is characterised in that the connection circuit includes the PMOS of multiple series connection, Every PMOS lock end is all electrically connected to corresponding multiplexer.

14. integrated circuit as claimed in claim 11, it is characterised in that the connection circuit includes number with the plurality of multiplexer Individual PMOS, each PMOS body end are electrically connected to the static discharge bus.

15. integrated circuit as claimed in claim 9, it is characterised in that each input circuit further includes：