CN1845414A - Protection circuit for resisting power supply abrupt change - Google Patents
Protection circuit for resisting power supply abrupt change Download PDFInfo
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- CN1845414A CN1845414A CN 200610011803 CN200610011803A CN1845414A CN 1845414 A CN1845414 A CN 1845414A CN 200610011803 CN200610011803 CN 200610011803 CN 200610011803 A CN200610011803 A CN 200610011803A CN 1845414 A CN1845414 A CN 1845414A
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- 230000001681 protective effect Effects 0.000 claims abstract description 33
- 238000001514 detection method Methods 0.000 claims abstract description 26
- 238000007493 shaping process Methods 0.000 claims description 11
- 230000005669 field effect Effects 0.000 claims description 3
- 229910044991 metal oxide Inorganic materials 0.000 claims description 3
- 150000004706 metal oxides Chemical class 0.000 claims description 3
- 230000035772 mutation Effects 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 3
- 230000006378 damage Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 101100433727 Caenorhabditis elegans got-1.2 gene Proteins 0.000 description 1
- 208000027418 Wounds and injury Diseases 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 208000014674 injury Diseases 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
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- Semiconductor Integrated Circuits (AREA)
Abstract
The protection circuit anti abrupt change of power comprises: a detection circuit to output an effective detection signal for power abrupt change, and a production circuit for protective voltage to output the protective voltage between the maximal and minimal values normally to the target. This invention can improve the circuit reliability.
Description
Technical field
The present invention relates to a kind of protective circuit that is used for resisting power supply abrupt change.
Background technology
Integrated circuit (IC)-components has certain withstand voltage scope, and the voltage above being added in it surpasses after the certain limit, and device will damage or reliability is caused very big injury.This withstand voltage scope is determined by technology, a little higher than supply voltage of common design.In the actual use of circuit, when just powering up, when perhaps supply voltage switches, when perhaps the abnormity of power supply fluctuation is big, if the unreasonable or improper use of power supply design, the output voltage of power supply can upper punches, surpass normal working voltage in a big way and keep a period of time.
Prevent that by employing ESD (static discharge) device or diode clamping circuit mains voltage variations from damaging device in the prior art.But the ESD device is used for electrostatic protection, is not very high for this voltage, and long-term power supply sudden change can't be made a response usually, thereby can not reach the corresponding protection function.Thereby need being provided with usually, diode clamping circuit influences circuit working when rational threshold value is avoided operate as normal.But the threshold value of diode is normally fixed, and in integrated circuit, be difficult to realize integrated, the skew of similar its threshold value of diode circuit that employing mosfet (metal oxide field effect transistor npn npn) constitutes is bigger, and the I-V curve is also precipitous inadequately, thereby has increased power consumption and design difficulty.
Therefore need a kind of circuit, can protective circuit when the supply voltage upper punch in responsive device, make the voltage at its two ends be no more than certain limit.Sort circuit can not influence the operate as normal of circuit again simultaneously.
Summary of the invention
The technical problem to be solved in the present invention provides a kind of protective circuit of resisting power supply abrupt change; when the supply voltage upper punch; can be in a period of time the device in the protective circuit, its both end voltage is remained in the reasonable range, thereby avoids the circuit reliability problem.
In order to solve the problems of the technologies described above, the invention provides a kind of protective circuit of resisting power supply abrupt change, it is characterized in that, comprise a protection voltage generation circuit and power supply sudden change testing circuit, wherein:
Described power supply sudden change testing circuit is used for supply voltage is detected, when supply voltage is undergone mutation, and output one effective detection signal;
Described protection voltage generation circuit is used for when this detection signal is effective, and ceiling voltage and protection voltage minimum voltage between of output one when the circuit operate as normal arrives the Sensitive Apparatus that needs protection.
Further; above-mentioned protective circuit also can have following characteristics: also comprise a logical circuit; be used to receive a described detection signal and an external control signal; when detection signal is effective; the output effective control signal is to described protection voltage generation circuit; make its output protection voltage, when detection signal is invalid, determine the effective or invalid of this logic circuit output signal by described external control signal.
Further; above-mentioned protective circuit also can have following characteristics: described protection voltage generation circuit comprises a switch and a bleeder circuit that is connected between power supply and the ground; the conducting when described detection signal or logic circuit output signal are effective of described switch; open when invalid; when this switch conduction, export described protection voltage from described bleeder circuit intermediate node.
Further; above-mentioned protective circuit also can have following characteristics: described power supply sudden change testing circuit comprises a RC circuit and a shaping circuit that is connected between power supply and the ground; the output of the intermediate node of this RC circuit is connected to this shaping circuit, this shaping circuit to the input signal shaping after the detection signal of output switching value.
Further; above-mentioned protective circuit also can have following characteristics: described shaping circuit is an inverter; deserve RC circuit intermediate node output voltage when being higher than the threshold value of this inverter; this inverter output one effective low level square-wave signal; when RC circuit intermediate node output voltage was lower than the threshold value of this inverter, this inverter was exported an invalid high level square-wave signal.
Further; above-mentioned protective circuit also can have following characteristics: the detection signal low level of described power supply sudden change testing circuit output is effective; described logical circuit is a NAND gate, when it is output as high level, controls described protection voltage generation circuit output protection voltage.
Further, above-mentioned protective circuit also can have following characteristics: described logical circuit also comprises an inverter, and described external control signal is imported earlier described NAND gate again behind this inverter.
Further, above-mentioned protective circuit also can have following characteristics: described bleeder circuit is a resistor voltage divider circuit or metal oxide field effect transistor npn npn bleeder circuit.
Further; above-mentioned protective circuit also can have following characteristics: also comprise a switch that is connected between protection voltage output node and ground voltage or the minimum voltage; the control end of this switch is connected to the output of logical circuit control signal by an inverter; export when effective at this logical circuit and to disconnect, export conducting when invalid at this logical circuit.
As from the foregoing, the protective circuit of resisting power supply abrupt change provided by the invention when the supply voltage upper punch, can be in a period of time the device in the protective circuit, its both end voltage is remained in the reasonable range, thereby avoids the circuit reliability problem.And can reduce the power consumption of circuit by introducing the control signal of other module.
Description of drawings
Fig. 1 is the circuit diagram of the embodiment of the invention.
Fig. 2 is the circuit diagram of another embodiment of the present invention.
Embodiment
For when the supply voltage upper punch, the device in a period of time in the protective circuit remains in the reasonable range its both end voltage, and the present invention has designed a kind of protective circuit, and Fig. 1 is an embodiment of protective circuit of the present invention.As shown in the figure, this circuit comprises protection voltage generation circuit 1, power supply sudden change testing circuit 2 and logical circuit 3.Wherein:
Protection voltage generation circuit 1 is used to produce the intermediate level output voltage of (referring to the voltage between the ceiling voltage and minimum voltage when the circuit operate as normal), promptly protects voltage, and present embodiment is got 1/2Vdd, and wherein Vdd is a supply voltage.Adopt resistor voltage divider circuit to realize at present embodiment; this circuit comprises K switch 1, resistance R 1 and the resistance R 2 that is connected the mutual polyphone between power supply and the ground; its output node U1 is the node between resistance R 1 and the R2; it is the intermediate node of bleeder circuit; be connected with an end of the Sensitive Apparatus that will protect, the other end of this Sensitive Apparatus is connected with power supply or ground.In this case, can make the voltage on the Sensitive Apparatus can not surpass protection voltage, i.e. 1/2Vdd all the time.The situation that might bear Vdd during with unprotected circuit is compared, and the source-drain voltage that bears on the Sensitive Apparatus has reduced half.In another embodiment, also can be without electric resistance partial pressure, with the mosfet dividing potential drop also can, in addition, if there is a fixing intermediate level just not need to be provided with again above-mentioned bleeder circuit directly as protection voltage.
The K switch 1 of contacting in this circuit is arranged on the upper end of R1 in the drawings, but also can be arranged on other position, such as between R1 and the R2, the R2 lower end, controlled by logical circuit 3 output signals, when logical circuit 3 outputs are effective, K switch 1 conducting, when invalid, K switch 1 is opened.Only when K switch 1 conducting, protective circuit just produces the output voltage of an intermediate level as protecting voltage to sensitive nodes.
Power supply sudden change testing circuit 2 is made up of a RC circuit and an inverter I1 in the present embodiment.Power supply is connected with capacitor C one end, and the other end of capacitor C is connected with resistance R 3, and the other end of R3 is connected with ground, and R3 and capacitor C can use mosfet to constitute, thereby reduce area.
In normal operation, the node that links to each other with capacitor C of resistance R 3 is an electronegative potential.When power supply upwards suddenlys change,, and then slowly be reduced to electronegative potential by the discharge process of resistance R 3 because the characteristic of capacitor C makes this node voltage will upwards suddenly change equally.This node voltage is carried out shaping by inverter I1, can export a square wave as detection signal, when the square wave level is high, show the power supply operate as normal, this detection signal is invalid, when the square wave level is low, shows that sudden change has taken place power supply, and this detection signal is effective.Inverter I1 has a threshold value, output high level when input voltage is lower than this threshold value, output low level when input voltage is higher than this threshold value, by adjusting the threshold value of inverter I1, can control the node voltage size that makes when output square wave level is low, cause false triggering when avoiding voltage fluctuation.Adjust the value of resistance R and capacitor C, then can control square wave is the low duration.After the RC circuit discharging finished, the RC intermediate node voltage was lower than the inverter threshold value, is output as high level, and it is invalid detecting voltage.
Continue to consume power consumption when the powerdown of system state (shutdown mode or battery saving mode) for fear of entire circuit, can introduce a control signal pd from other module.Signal pd is effective under the system powerdown state, and control switch K1 opens.But when just powering in system, therefore possible each control signal and unexpected value might cause this protective circuit work that the voltage of node can not correctly be set.Therefore, present embodiment is provided with a logical circuit 3.This logical circuit is finished following work: when power supply sudden change testing circuit output signal effective (power supply is undergone mutation), logic circuit output signal makes K switch 1 conducting, and protection voltage generation circuit output protection voltage is realized the protection to Sensitive Apparatus.At this moment, should shield the influence of control signal pd, thereby make that the whole protecting circuit is in running order switch K1.When the output of power supply sudden change testing circuit was invalid, then the output of logical circuit was decided by external control signal pd, thereby the operating state of this part can rationally be set according to the needs of whole system, as realizing the function of power saving, or other function.
As shown in the figure, logical circuit 3 is made up of an inverter I2 and a NAND gate, and external control signal pd is after inverter I2 is anti-phase and the output of power supply sudden change testing circuit input nand gate together.Because the detection signal of power supply sudden change testing circuit is effective in low level, therefore, when this detection signal is effective, no matter the pd signal is a height is low, the output one of NAND gate is decided to be high level, can control switch K1 conducting, and when this detection signal be high level, when being invalid, then the pd signal may control switch K1 conducting or open.Certainly the element of this logical circuit and concrete structure and signal be high level effectively or low level is effectively relevant, such as not necessarily inverter I2 to be set.In addition, if in the power supply sudden change testing circuit inverter is not set, and is a buffer, it is effective to make that detection signal is output as high level, then this logical circuit also can adopt one or, this transfer pair those skilled in the art's technical staff shows you and easily sees.
On the basis of the foregoing description, the present invention can also have various conversion.For example, in another embodiment,, then do not introduce external control signal pd, can not want logical circuit in this protective circuit, directly come the conducting of control switch K1 and open with detection signal if there is not the powerdown state.
In another embodiment; because in some system; under the powerdown state; protection voltage generation circuit 1 need be set to another fixed level; be generally vss; be minimum voltage or ground voltage, then need on the basis of Fig. 1 circuit, increase the K switch 2 that a drop-down mosfet constitutes, this switch be connected and the intermediate node of divider resistance circuit between.As shown in Figure 2.The control end of this K switch 2 is controlled by the output signal that an inverter I3 is connected to logical circuit 3; when the control signal of this logical circuit output is effective; K switch 1 conducting; K2 disconnects; output protection voltage, and when the control signal of this logical circuit was invalid, K switch 1 disconnected; the K2 conducting can pull down to vss with node power.This circuit has three states: the normal and battery saving mode of power supply, and the normal and operate as normal of power supply, whether power supply is undesired, like this at power supply just often, dragged down and depend on outside pd signal.
Claims (9)
1, a kind of protective circuit of resisting power supply abrupt change is characterized in that, comprises a protection voltage generation circuit and power supply sudden change testing circuit, wherein:
Described power supply sudden change testing circuit is used for supply voltage is detected, when supply voltage is undergone mutation, and output one effective detection signal;
Described protection voltage generation circuit is used for when this detection signal is effective, and ceiling voltage and protection voltage minimum voltage between of output one when the circuit operate as normal arrives the Sensitive Apparatus that needs protection.
2, protective circuit as claimed in claim 1; it is characterized in that; also comprise a logical circuit; be used to receive a described detection signal and an external control signal; when detection signal was effective, the output effective control signal made its output protection voltage to described protection voltage generation circuit; when detection signal is invalid, determine the effective or invalid of this logic circuit output signal by described external control signal.
3, protective circuit as claimed in claim 1 or 2; it is characterized in that; described protection voltage generation circuit comprises a switch and a bleeder circuit that is connected between power supply and the ground; the conducting when described detection signal or logic circuit output signal are effective of described switch; open when invalid; when this switch conduction, export described protection voltage from described bleeder circuit intermediate node.
4, protective circuit as claimed in claim 1; it is characterized in that; described power supply sudden change testing circuit comprises a RC circuit and a shaping circuit that is connected between power supply and the ground; the output of the intermediate node of this RC circuit is connected to this shaping circuit, this shaping circuit to the input signal shaping after the detection signal of output switching value.
5, protective circuit as claimed in claim 4; it is characterized in that; described shaping circuit is an inverter; deserve RC circuit intermediate node output voltage when being higher than the threshold value of this inverter; this inverter output one effective low level square-wave signal; when RC circuit intermediate node output voltage was lower than the threshold value of this inverter, this inverter was exported an invalid high level square-wave signal.
6, protective circuit as claimed in claim 2; it is characterized in that the detection signal low level of described power supply sudden change testing circuit output is effective, described logical circuit is a NAND gate; when it is output as high level, control described protection voltage generation circuit output protection voltage.
7, protective circuit as claimed in claim 6 is characterized in that, described logical circuit also comprises an inverter, and described external control signal is imported earlier described NAND gate again behind this inverter.
8, protective circuit as claimed in claim 3 is characterized in that, described bleeder circuit is a resistor voltage divider circuit or metal oxide field effect transistor npn npn bleeder circuit.
9, protective circuit as claimed in claim 2; it is characterized in that; also comprise a switch that is connected between protection voltage output node and ground voltage or the minimum voltage; the control end of this switch is connected to the output of logical circuit control signal by an inverter; export when effective at this logical circuit and to disconnect, export conducting when invalid at this logical circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610011803 CN100561818C (en) | 2006-04-27 | 2006-04-27 | A kind of protective circuit of resisting supply voltage sudden change |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200610011803 CN100561818C (en) | 2006-04-27 | 2006-04-27 | A kind of protective circuit of resisting supply voltage sudden change |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1845414A true CN1845414A (en) | 2006-10-11 |
| CN100561818C CN100561818C (en) | 2009-11-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200610011803 Expired - Fee Related CN100561818C (en) | 2006-04-27 | 2006-04-27 | A kind of protective circuit of resisting supply voltage sudden change |
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| Country | Link |
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| CN (1) | CN100561818C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103907186A (en) * | 2011-11-01 | 2014-07-02 | 高通股份有限公司 | Block power switch with embedded electrostatic discharge (ESD) protection and adaptive body biasing |
| CN104390738A (en) * | 2014-12-16 | 2015-03-04 | 济南优耐特汽车电子有限公司 | Oil pressure sensor circuit |
| CN107885304A (en) * | 2015-10-22 | 2018-04-06 | 深圳拓邦股份有限公司 | A kind of voltage jump detects circuit |
-
2006
- 2006-04-27 CN CN 200610011803 patent/CN100561818C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103907186A (en) * | 2011-11-01 | 2014-07-02 | 高通股份有限公司 | Block power switch with embedded electrostatic discharge (ESD) protection and adaptive body biasing |
| CN104390738A (en) * | 2014-12-16 | 2015-03-04 | 济南优耐特汽车电子有限公司 | Oil pressure sensor circuit |
| CN107885304A (en) * | 2015-10-22 | 2018-04-06 | 深圳拓邦股份有限公司 | A kind of voltage jump detects circuit |
| CN107885304B (en) * | 2015-10-22 | 2021-03-30 | 深圳拓邦股份有限公司 | Voltage sudden change detection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100561818C (en) | 2009-11-18 |
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Granted publication date: 20091118 Termination date: 20120427 |