CN109600133A

CN109600133A - It can be avoided the circuit of the damage of overvoltage

Info

Publication number: CN109600133A
Application number: CN201710915197.5A
Authority: CN
Inventors: 余家纬; 朱宏镇; 陈永泰
Original assignee: Realtek Semiconductor Corp
Current assignee: Realtek Semiconductor Corp
Priority date: 2017-09-30
Filing date: 2017-09-30
Publication date: 2019-04-09
Anticipated expiration: 2037-09-30
Also published as: CN109600133B

Abstract

This application discloses the circuits for the damage that can be avoided overvoltage.Specifically, disclosed herein a kind of circuit of overvoltage damage that can be avoided operation starting and/or stop moment, one embodiment includes a protected circuit and a protection circuit.The protected circuit receives a supply voltage to operate, and includes: a protected component, and wherein a pressure resistance of the protected component is less than the supply voltage；And an at least functioning switch, it is used to according to an enable signal is enabled or the forbidden energy protected circuit.The protection circuit couples the protected component, and starts operation before a transformation of the enable signal, and to protect the protected circuit from damage caused by an overvoltage, wherein the overvoltage is greater than the pressure resistance of the protected component.

Description

It can be avoided the circuit of the damage of overvoltage

Technical field

The present invention relates to protection circuit, especially with respect to can be avoided operation starting and/or stop moment overvoltage The circuit of damage.

Background technique

When being designed for a certain circuit (such as operational amplifier or bias circuit) of electronic device, in order to lower Reach preferable efficiency under power consumption and less circuit area, can on the main signal path of the circuit using lower pressure resistance but The preferable component of efficiency, however, in power supply switching/supply moment or being received abnormal because the pressure resistance of the component is lower When voltage disturbance, the component received voltage may be more than the component pressure resistance the upper limit, to cause the longevity of the component Life reduces or damage.To avoid the above problem, certain prior arts provide general common voltage protection for no pressure resistance of component Circuit, however, the problems such as such voltage protection circuit may reduce the efficiency of protected circuit or cause electric leakage.

Summary of the invention

A purpose of the present invention is that providing a kind of circuit, can be avoided operation starting and/or stopping the overvoltage of moment Damage, to protect the low pressure-resistant component in the circuit.

Disclosed herein a kind of circuit of damage that can be avoided overvoltage, one embodiment includes a protected circuit With a protection circuit.The protected circuit is used to generate an at least output signal according to an at least input signal, this is protected Circuit receives a supply voltage to operate, and includes: a protected component wherein should for receiving an at least input signal One pressure resistance of protected component is less than the supply voltage；And an at least functioning switch, be used to according to an enable signal it is enabled or The forbidden energy protected circuit.The protection circuit is coupled between a first end of the protected component and a second end, wherein The first end is used to receive an at least input signal, which switchs before a transformation of the enable signal according to one Signal starts operation, and to protect the protected component from the damage of an overvoltage, above-mentioned overvoltage is greater than the protected component The pressure resistance.

Another embodiment of the circuit of the damage that can be avoided overvoltage of the invention includes that a protected circuit is protected with one Protection circuit.The protected circuit receives a supply voltage to operate, and includes: a protected component, and wherein this protected group One pressure resistance of part is less than the supply voltage；And an at least functioning switch, it is used to according to an enable signal is enabled or forbidden energy should be by Protect circuit.The protection circuit couples the protected component, and the protection circuit is before a transformation of the enable signal, according to one Switching signal starts operation, and to protect the protected component from the damage of an overvoltage, wherein the overvoltage, which was greater than, to be protected The pressure resistance of protecting assembly.

In one embodiment of this invention, aforementioned protection circuit is during the supply of the supply voltage, and constantly protection should Protected component, no matter whether the protected component is enabled.

In one embodiment of this invention, aforementioned protection circuit includes an at least protective switch, an at least protective switch For according to the switching signal is enabled or the forbidden energy protection circuit, wherein before the transformation of aforementioned enable signal, protection electricity Road is first enabled.

Feature, implementation and effect for the present invention, hereby schema being cooperated to make preferred embodiment, detailed description are as follows.

Detailed description of the invention

[Fig. 1] shows an embodiment of the circuit of the damage that can be avoided overvoltage of the invention；

[Fig. 2] shows the protected circuit of Fig. 1 and an embodiment of protection circuit；

[Fig. 3] shows the protected circuit of Fig. 1 and another embodiment of protection circuit；

[Fig. 4] shows the protected circuit of Fig. 1 and another embodiment of protection circuit；

[Fig. 5] shows an embodiment of the control circuit of Fig. 1；And

[Fig. 6] shows the timing diagram and circuit state associated with signal of the signal of Fig. 5.

Specific embodiment

The term of following description is the idiom referring to the art, is added as this specification has part term To illustrate or define, the explanation of the part term is to be subject to the explanation or definition of this specification.

Disclosed herein a kind of circuit, can be enabled in the protected circuit in the circuit and/or forbidden energy before, It enables the protection circuit in the circuit or maintains the running of the protection circuit, avoid starting and/or forbidden energy moment whereby Overvoltage damages the low pressure-resistant component in the protected circuit.

Fig. 1 shows an embodiment of circuit of the invention.As shown in Figure 1, circuit 100 of the invention includes one protected Circuit 110, one protects circuit 120 and a control circuit 130.Protected circuit 110 receives a supply voltage V_DDWith running, and Include a protected component and an at least functioning switch (as shown in embodiment of the Fig. 2 to Fig. 4).Protected circuit 110 is protected The pressure resistance of protecting assembly is less than the supply voltage；Typically, pressure resistance refers to a patient upper voltage limit of protected component institute, changes Yan Zhi may damage this protected component more than the voltage of the upper voltage limit or shorten the service life of this protected component.It is protected An at least functioning switch for circuit 110 is used to according to an enable signal, enabled or forbidden energy protected circuit 110, protected circuit 110 are being enabled or the moment of forbidden energy, may receive the pressure resistance that an overvoltage is greater than one or more above-mentioned protected components, therefore Need to protect the protection of circuit 120.Circuit 120 is protected to couple the protected component of protected circuit 110, and in the enabled letter Number one transformation before start operation, to protect the protected component from the damage of above-mentioned overvoltage, the transformation of the enable signal Refer to that the transformation from forbidden energy protected circuit 110 to enabled protected circuit 110 (or is said from a forbidden energy level to an enabled electricity Flat transformation) and/or refer to that the transformation from enabled protected circuit 110 to forbidden energy protected circuit 110 (or is said from an enabled electricity Put down the transformation to a forbidden energy level)；In one embodiment, protection circuit 120 is according to a switching signal (such as the dotted line institute of Fig. 1 Show) to start operation or stop operating, to provide protection in running, which is to depend upon the enable signal herein (as shown in Figure 6)；In another embodiment, protect 120 continued operation of circuit to provide protection always, at this time the switching signal The i.e. inessential or switching signal be remain unchanged and it is unrelated with the enable signal.Control circuit 130, which is used to generate this, to be made Energy signal, and be optionally used for generating the switching signal, an embodiment of control circuit 130 includes a timing sequence generating circuit (as shown in the embodiment of FIG. 5) or its equivalent circuit.

Fig. 2 shows the protected circuit 110 of Fig. 1 and an embodiment of protection circuit 120.As shown in Fig. 2, protected electricity Road 110 is a folding Operational Amplifier (folded cascade operational amplifier), is used to differential according to one Input signal (V_IN+、V_IN) generate a differential output signal (V_OUT+、V_OUT), protected circuit 110 includes: a transistor pair 210 (PMOS transistor M1, M2 of Fig. 2), for receiving the differential wave；And multiple 220 (PMOS of Fig. 2 of functioning switch Transistor M4, M11, M12), for receive an enable signal POWDB to enable or forbidden energy protected circuit 110.To promote effect Can, transistor has high-effect but low pressure resistance to 210, therefore is easy to be damaged by an overvoltage, therefore transistor needs to be protected to 210 Shield and as protected component.Protecting circuit 120 includes multiple transistors (PMOS transistor MP1, MP2 of Fig. 2), is coupled to crystalline substance Body pipe is between 210 signal input part (grid) and signal output end (drain electrode)；Protect circuit 120 in enable signal POWDB Transformation before begin to running (that is, transistor MP1, MP2 of Fig. 2 be as protective switch, in the transformation of enable signal POWDB It is preceding to be just switched on), to be enabled and/or the moment of forbidden energy in protected circuit 110, limit transistor to 210 each crystal The cross-pressure of pipe, to protect transistor to 210 from damage caused by an overvoltage；In addition, protection circuit 120 is that foundation is opened OFF signal POWB_protect is enabled or forbidden energy, and provides protection against during being enabled, switching signal POWB_ Protect can be generated by the control circuit 130 or its equivalent circuit of Fig. 5.Due to other electricity of the folding operational amplifier of Fig. 2 The control on road (that is, transistor M3, M5~M10, M13~M16 and its connection) belongs to the usual knowledge of this field with running, therefore Correlative detail omits herein.

Fig. 3 shows the protected circuit 110 of Fig. 1 and another embodiment of protection circuit 120.Compared to Fig. 2, the guarantor of Fig. 3 Protection circuit 120 further includes transistor MD1 and transistor MD2, and transistor MD1 and transistor MD2 are diode connection (diode-connected) transistor serves as pressure limiting component, is used to determine transistor pair when protecting circuit 120 to provide protection A voltage difference between 210 signal input part and signal output end makes the voltage difference be not more than transistor in 210 whereby Any transistor pressure resistance；In addition, in one embodiment, the protection circuit 120 of Fig. 3 is according to switching signal POWB_ Protect is enabled or forbidden energy, and provides protection against during being enabled；In another embodiment, the protection electricity of Fig. 3 Road 120 is to receive supply voltage V in protected circuit 110_DDAfterwards, continue to provide guarantor according to switching signal POWB_protect Protective function (that is, switching signal POWB_protect remains unchanged with lasting unlatching transistor MP1, MP2, no matter protected electricity Whether road 110 is enabled), until supply voltage V_DDUntil not being supplied, in other words, equivalent upper transistor MP1, MP2 and switch Signal can be omitted herein.

Fig. 4 shows the protected circuit 110 of Fig. 1 and another embodiment of protection circuit 120.As shown in figure 4, protected Circuit 110 is a bias circuit, receives a bias V_B, and include: a transistor 410 (the PMOS transistor MB2 of Fig. 4, as by Protect component)；And a functioning switch 420 (the NMOS transistor MB4 of Fig. 4), for receiving enable signal POWD (its phase When in the inversion signal of aforementioned enable signal POWDB), to enable or forbidden energy protected circuit 110.For enhanced performance, transistor 410 have high-effect but low pressure resistance, therefore are easy to be damaged by an overvoltage, thus transistor 410 need it is to be protected and as being protected Protecting assembly.Protecting circuit 120 includes a transistor (the PMOS transistor MP1 of Fig. 4), is coupled to grid and the leakage of transistor 410 Between pole；Protection circuit 120 begins to running before the transformation of enable signal POWD, and (that is, the transistor MP1 of Fig. 2 is as one Protective switch is just switched on before the transformation of enable signal POWD), to be enabled in protected circuit 110 and/or when forbidden energy, Protect transistor 410 from damage caused by an overvoltage；In addition, protection circuit 120 is according to switching signal POWB_ Protect is enabled or forbidden energy, and provides protection against during being enabled, and switching signal POWB_protect can be by this time The control circuit 130 of Fig. 5 or its equivalent circuit generate.Due to other circuits (that is, transistor of the bias circuit of Fig. 4 MB1, MB3, MB5, MB6 and its connection) control belong to the usual knowledge of this field with running, therefore correlative detail omits herein.

It is worth noting that, in previous embodiment, each not protected transistor (such as the transistor of Fig. 2 and Fig. 3 The transistor MB1 and MB3~MB6 of M3, M5~M10 and M13~M16 and Fig. 4) pressure resistance (such as higher than supply voltage V_DD) Higher than the protected component (such as the transistor of Fig. 2 and Fig. 3 is to transistor MB2 of 210 and Fig. 4) pressure resistance (such as less than Supply voltage V_DD), however under the premise of being embodied as possible, the implementation limitation of this and non-present invention.Though it is another it is worth noting that, In the embodiment of right Fig. 2 to Fig. 4, protection circuit 120 is coupled between the grid and drain electrode of the protected component, however this is not It is implementation limitation of the invention；Protection circuit of the invention can be coupled to two ends of any required protected components/circuits, with Realize protection effect, for example, when the protected component is a transistor, protection circuit of the invention can be coupled to the crystalline substance Between the drain electrode and source electrode of body pipe.

Fig. 5 shows an embodiment of the control circuit 130 of Fig. 1.As shown in figure 5, control circuit 130 includes a deferred telegram Road 510, one first logic gates 520 and one second logic gates 530.Delay circuit 510 is used to postpone a control signal The output of POW is up to a predetermined time, to generate a postpones signal DS.First logic gates 520 includes: one or door (OR Gate) 522, it is used to generate a reverse phase enable signal POWD according to postpones signal DS and control signal POW；An and phase inverter 524, it is used to generate aforementioned enable signal POWDB according to reverse phase enable signal POWD.Second logic gates 530 includes: one with NOT gate (NAND gate) 532 is used to generate a phase-veversal switch signal POW_ according to postpones signal DS and control signal POW protect；And a phase inverter 534, it is used to generate aforementioned switches signal POWB_ according to phase-veversal switch signal POW_protect protect.The timing diagram of above-mentioned each signal and protected circuit 110 associated with signal and the state for protecting circuit 120 As shown in fig. 6, wherein POWB is the inversion signal for controlling signal POW, label " on " and " off " respectively represent the state of circuit For " enabled " and " forbidden energy ", in addition, the waveform of each signal is only to illustrate, it is non-to limit the present invention.It note that view implementation demand While being made of NMOS (such as the functioning switch and/or protective switch of Fig. 2 to Fig. 4), the phase inverter 524 and/or phase inverter of Fig. 5 534 are dispensed, at this point, the enable signal is POWD and/or the switching signal is POW_protect.Separately it note that One skilled in the art's available equivalents are in known to control circuit 130 or independently developed circuit generates the enabled letter Number and/or the switching signal；Or one skilled in the art can be generated with other known or independently developed circuit The enable signal and/or the switching signal, as long as switching signal caused by other circuits can turn in the enable signal Before change, protection circuit is enabled.

It note that under the premise of being embodied as possible, before the art tool usually intellectual optionally implements Part or all technical features in any embodiment are stated, or selectively implement part or all of technology in aforesaid plurality of embodiment The combination of feature increases the elasticity when present invention is implemented whereby.It separately note that and implement present inventor, can be determined according to its demand The transistor varieties (such as PMOS transistor and NMOS transistor) of functioning switch and protection circuit.

In conclusion the overvoltage that circuit of the invention can be avoided starting moment makes the low pressure-resistant component in the circuit At damage, therefore, circuit of the invention can reach preferable circuit performance by the low pressure-resistant component, and ensure the low pressure-resistant group The reliability and service life of part.In addition, being indebted to circuit protection design of the invention, the manufacture of circuit of the invention be can be used The CMOS processing procedure of general standard, the pressure-resistant degree without low pressure-resistant component of especially worrying.

Although the embodiment of the present invention is as described above, however those embodiments not are used to limit the present invention, this technology neck The domain tool usually intellectual content that can express or imply according to the present invention imposes variation to the technical characteristic of the present invention, it is all this Many variations may belong to patent protection scope sought by the present invention, and in other words, scope of patent protection of the invention must regard Subject to the as defined in claim of this specification.

[symbol description]

100 can be avoided the circuit of the overvoltage damage of operation start and stop moment

110 protected circuits

120 protection circuits

130 control circuits

V_DDSupply voltage

210 transistors are to (protected component)

220 transistors (functioning switch)

M1~M16 transistor

MP1, MP2 transistor (protective switch)

V_IN+、V_INDifferential input signals

V_OUT+、V_OUTDifferential output signal

POWDB enable signal

POWB_protect switching signal

MD1, MD2 transistor (pressure limiting component)

410 transistors (protected component)

420 transistors (functioning switch)

MB1~MB6 transistor

MP1 transistor (protective switch)

V_BBias

510 delay circuits

520 first logic gates

522 or door (OR gate)

524 phase inverters

530 second logic gates

532 NAND gates (NAND gate)

534 phase inverters

POW controls signal

DS postpones signal

POWD reverse phase enable signal

POW_protect phase-veversal switch signal

On circuit is enabled

Off circuit is disabled

Claims

1. a kind of circuit for the damage that can be avoided overvoltage, includes:

One protected circuit generates an at least output signal according to an at least input signal, which receives a power supply Voltage includes to operate:

One protected component, for receiving an at least input signal；And

An at least functioning switch is used to according to an enable signal is enabled or the forbidden energy protected circuit；And

One protection circuit, is coupled between a first end of the protected component and a second end, and wherein the first end is used to connect An at least input signal is received, which starts operation before a transformation of the enable signal according to a switching signal, with Protect the protected component from the damage of an overvoltage, which is greater than a pressure resistance of the protected component.

2. can be avoided the circuit of the damage of overvoltage as described in claim 1, wherein the protected component is a transistor Right, which is two grids of the transistor pair, which is two drain electrodes or two source electrodes of the transistor pair.

3. can be avoided the circuit of the damage of overvoltage as described in claim 1, wherein the protection circuit includes that a protection is opened It closes, the protective switch is according to the switching signal is enabled or the forbidden energy protection circuit, to enable before the transformation of the enable signal The protection circuit.

4. as claimed in claim 3 can be avoided overvoltage damage circuit, wherein the protection circuit further include to A few pressure limiting component, an at least pressure limiting component are used to limit one between the first end of the protected component and the second end Voltage.

5. can be avoided the circuit of the damage of overvoltage as claimed in claim 3, further include: a control circuit is used to Signal, which is controlled, according to one generates the enable signal and the switching signal.

6. can be avoided the circuit of the damage of overvoltage as claimed in claim 5, wherein the control circuit includes:

One delay circuit is used to generate a postpones signal according to the control signal；

One first logic gates, for generating the enable signal according to the postpones signal and the control signal；And

One second logic gates, for generating the switching signal according to the postpones signal and the control signal, wherein this second Logic gates is different from first logic gates.

7. a kind of circuit for the damage that can be avoided overvoltage, includes:

One protected circuit receives a supply voltage to operate, includes:

One protected component；And

One protection circuit, couples the protected component, and the protection circuit is before a transformation of the enable signal, according to a switch letter It number starts operation, to protect the protected component from the damage of an overvoltage, wherein the overvoltage is greater than the protected component One pressure resistance.

8. can be avoided the circuit of the damage of overvoltage as claimed in claim 7, wherein the protection circuit is in the supply voltage One supply during continued operation.

9. can be avoided the circuit of the damage of overvoltage as claimed in claim 7, wherein the protection circuit is protected comprising at least one Shield switch, for an at least protective switch according to the switching signal is enabled or the forbidden energy protection circuit, which made in this Before the transformation of energy signal, the protection circuit is enabled.

10. can be avoided the circuit of the damage of overvoltage as claimed in claim 9, further include: a control circuit is used to Signal, which is controlled, according to one generates the enable signal and the switching signal.