CN103780235A - Power supply reset circuit - Google Patents
Power supply reset circuit Download PDFInfo
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- CN103780235A CN103780235A CN201210424947.6A CN201210424947A CN103780235A CN 103780235 A CN103780235 A CN 103780235A CN 201210424947 A CN201210424947 A CN 201210424947A CN 103780235 A CN103780235 A CN 103780235A
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- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000009792 diffusion process Methods 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
- 229910021420 polycrystalline silicon Inorganic materials 0.000 claims description 3
- 229920005591 polysilicon Polymers 0.000 claims description 3
- 239000004065 semiconductor Substances 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 abstract description 18
- 230000000630 rising effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 8
- 238000009434 installation Methods 0.000 description 5
- 230000007704 transition Effects 0.000 description 4
- 230000003071 parasitic effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
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Abstract
The invention discloses a power supply reset circuit which comprises an inverter, a voltage control unit, a capacitor and a discharge unit. The voltage control unit is coupled between the power voltage and the input end of the inverter, and the capacitor and the discharge unit are coupled between the input end of the inverter and the ground. The voltage at the input end of the inverter is pulled down to the ground voltage level through a discharge path provided by the discharge unit, so that the reset signal can be generated correctly. The power supply reset circuit can avoid the influence of the rising/falling speed of the power supply on the generation of the reset signal and correctly generate the reset signal.
Description
Technical field
The invention relates to a kind of power supply reset circuit, and relate to especially a kind of power supply reset circuit that can correctly produce reset signal.
Background technology
In the time of design electronic circuit, tend to add replacement (reset) mechanism in circuit, so that designed electronic circuit is replied when needed as initial condition.
Fig. 1 illustrates the schematic diagram into existing power supply reset circuit.Please refer to Fig. 1, power supply reset circuit 100 comprises anti-phase Schmidt trigger 102 (invert Schmitt trigger), transistor Q1 and capacitor C 1.Wherein transistor Q1 is coupled between voltage source VDD and the input of anti-phase Schmidt trigger 102, and capacitor C 1 is coupled between the input and ground connection of anti-phase Schmidt trigger 102.
As shown in Figure 1, the change in voltage on the input of anti-phase Schmidt trigger 102 is depended in the output of the reset signal S1 of power supply reset circuit 100, that is voltage swing in capacitor C 1 changes.And because the usefulness that discharges and recharges of capacitor C 1 can change to some extent with power supply rise/fall speed difference, therefore often there will be the reset signal S1 that cannot correctly produce expection, and then cause system to work as machine or undesired.For instance, as voltage source VDD, because certain is former thereby while declining, electric energy stored in capacitor C 1 will flow to supply voltage VDD by transistor Q1, and cross-pressure in capacitor C 1 is declined.In the time that the cross-pressure in capacitor C 1 drops to the transition level of anti-phase Schmidt trigger 102, the reset signal S1 that anti-phase Schmidt trigger 102 just can be exported a logic high in its output according to the voltage level of its input, with reset system, avoids system to cause the generation of misoperation because the supply voltage VDD receiving is too low.
Because existing power supply reset circuit 100 is for to discharge towards supply voltage VDD, this discharge path easily has parasitic capacitance effect and makes the decrease in efficiency of capacitor C 1.When the velocity of discharge in capacitor C 1 is crossed when slow, to make cross-pressure in capacitor C 1 cannot immediately drop to the transition level of anti-phase Schmidt trigger 102, will make anti-phase Schmidt trigger 102 to export reset signal S1 in its output, and and then make system cause not expected state to occur because supply voltage VDD is too low.When supply voltage VDD replys after normal working voltage, system will cannot normally be worked because of its internal signal entanglement.
Summary of the invention
The invention provides a kind of power supply reset circuit, can avoid the generation of reset signal to be subject to power supply rise/fall rate, and correctly produce reset signal.
The present invention proposes a kind of power supply reset circuit, comprises inverter, voltage control unit, electric capacity and discharge cell.Voltage control unit is coupled between supply voltage and the input of inverter, according to the voltage transmission path between the input of supply voltage powered-down voltage and inverter.Electric capacity is coupled between the input and ground connection of inverter.Discharge cell is coupled between the input and ground connection of inverter, a discharge path is provided in the time that supply voltage declines, and makes the voltage of the input of inverter be down to the voltage level of ground connection.
In one embodiment of this invention, when supply voltage is during lower than predeterminated voltage, the voltage transmission path between the input of voltage control unit powered-down voltage and inverter.
In one embodiment of this invention, above-mentioned voltage control unit comprises the first transistor, and its grid and drain electrode couple supply voltage, and the source electrode of the first transistor couples the input of inverter.
In one embodiment of this invention, the critical voltage that above-mentioned predeterminated voltage is the first transistor.
In one embodiment of this invention, above-mentioned discharge cell comprises resistance, is coupled between the input and ground connection of inverter.
In one embodiment of this invention, above-mentioned resistance is polysilicon resistance, diffusion resistance or vague and general type metal-oxide semiconductor transistor.
In one embodiment of this invention, above-mentioned inverter is anti-phase Schmidt trigger.
In one embodiment of this invention, above-mentioned current limliting unit is coupled between supply voltage and voltage control unit, flows to the size of current of voltage control unit in order to restriction.
In one embodiment of this invention, above-mentioned current limliting unit comprises transistor seconds, and its grid couples ground connection, and the source electrode of transistor seconds is coupled to supply voltage, and the drain electrode of transistor seconds couples voltage control unit.
In one embodiment of this invention, above-mentioned current limliting unit comprises current-limiting resistance, is coupled between supply voltage and voltage control unit.
Based on above-mentioned, the discharge path that the present invention provides by discharge cell, is pulled low to ground voltage level by the voltage of the input of inverter rapidly, to guarantee that reset signal can correctly be produced, and avoids causing system to work as machine or undesired.
For above-mentioned feature and advantage of the present invention can be become apparent, special embodiment below, and coordinate appended graphic being described in detail below.
Accompanying drawing explanation
Fig. 1 illustrates the schematic diagram into existing power supply reset circuit.
Fig. 2 illustrates the schematic diagram into the power supply reset circuit of one embodiment of the invention.
Fig. 3 illustrates the schematic diagram into the power supply reset circuit of another embodiment of the present invention.
Fig. 4 illustrates the schematic diagram into the power supply reset circuit of another embodiment of the present invention.
Wherein, description of reference numerals is as follows:
100,200,300,400: power supply reset circuit;
102: anti-phase Schmidt trigger;
202: current limliting unit;
204: voltage control unit;
206: discharge cell;
208: inverter;
C1, CL: electric capacity;
S1, SR1: reset signal;
VDD: voltage source;
Q1, Q2, MN1: transistor;
R1, RL: current-limiting resistance.
Embodiment
Fig. 2 illustrates the schematic diagram into the power supply reset circuit of one embodiment of the invention.Please refer to Fig. 2, power supply reset circuit 200 comprises current limliting unit 202, voltage control unit 204, discharge cell 206, capacitor C L and inverter 208.Wherein current limliting unit 202 couples supply voltage VDD, voltage control unit 204 is coupled between current limliting unit 202 and the input of inverter 208, discharge cell 206 is coupled between the input and ground connection of inverter 208, and capacitor C L is coupled between the input and ground connection of inverter 208.Wherein inverter 208 can be for example an anti-phase Schmidt trigger, and the current potential of its state switching points can be adjusted according to practical application situation.
Wherein, current limliting unit 202 flows to the size of current of voltage control unit 204 in order to restriction.Voltage control unit 204 is in order to the voltage transmission path between the input according to supply voltage VDD powered-down voltage VDD and inverter 208, for example, when supply voltage VDD is during lower than a predeterminated voltage, voltage control unit 204 is the voltage transmission path between the input of powered-down voltage VDD and inverter 208 just.206 of discharge cells provide a discharge path in the time that supply voltage VDD declines, and make the voltage of the input of inverter 208 be down to the voltage level of ground connection.So, just can guarantee the reset signal SR1 of the output output HIGH voltage level of inverter 208, and make the electronic installation (not illustrating) of applied power source reset circuit 200 enter the state of replacement.
And in the time that supply voltage VDD raises once again and is greater than predeterminated voltage, voltage transmission path between the input of voltage control unit 204 power-on voltage VDD and inverter 208, supply voltage VDD is able to capacitor C L to charge, and the voltage of the input of inverter 208 is raise.In the time that the voltage of the input of inverter 208 is increased to the transition voltage of inverter 208, reset signal SR1 just transfers low voltage level to and finishes the Reset Status of electronic installation.
As mentioned above, the discharge path providing by discharge cell 206 can make the voltage of the input of inverter 208 be down to rapidly the voltage level of ground connection, thereby can guarantee the startup of the Reset Status of electronic installation, cause the situation of misoperation to occur because the supply voltage VDD receiving is too low and do not have system.
Fig. 3 illustrates the schematic diagram into the power supply reset circuit of another embodiment of the present invention.Please refer to Fig. 3, in the present embodiment, current limliting unit 202 comprises a transistor Q2, and its grid couples ground connection, and source electrode is coupled to supply voltage VDD, and drain electrode couples voltage control unit 204.Current limliting unit 202 can also other modes be implemented in other embodiments, the schematic diagram of the power supply reset circuit 400 of example another embodiment of the present invention as shown in Figure 4, implement in the mode that a current-limiting resistance R1 is coupled between supply voltage VDD and voltage control unit 204, the execution mode of current limliting unit 202 is not limited with the present embodiment.The not necessary member of power supply reset circuit of current limliting unit 202 that it should be noted that above-described embodiment, therefore user can do and increase and decrease according to actual needs.
In the time that supply voltage VDD drops to lower than predeterminated voltage (predeterminated voltage is the critical voltage of transistor MN1 in the present embodiment), transistor MN1 will enter closed condition, and block the voltage transfer path between supply voltage VDD and inverter 208.Now supply voltage VDD is no longer to capacitor C L charging, and therefore the former electric charge being stored in capacitor C L can flow to ground connection via resistance R L.Because this discharge path is directly to flow to ground connection by resistance R L, can be just like the discharge path that flows to supply voltage VDD as prior art, there is parasitic capacitance and have the situation of discharge failure.Discharge and can make voltage on inverter 208 inputs drop to rapidly to level off to zero volt spy's earthing potential by resistance R L, and can guarantee the reset signal SR1 of inverter 208 output HIGH voltage level, make the electronic installation of applied power source reset circuit 200 enter Reset Status.
In addition, when supply voltage VDD slowly recovers, during higher than the critical voltage of transistor MN1, transistor MN1 is unlocked, and makes supply voltage VDD can start capacitor C L to charge, and improves the voltage on inverter 208 inputs.When the voltage on inverter 208 inputs is during higher than inverter 208, reset signal SR1 just transfers low voltage level to, and makes electronic installation depart from Reset Status.
Wherein, while starting to provide voltage when supply voltage VDD rising, owing to there being the existence of pair earth-current, therefore can postpone inverter 208 inputs to power on the high time of voltage rise, and make inverter 208 can produce the reset signal of safe time enough length.
In addition, when the voltage on inverter 208 inputs cannot provide voltage by transistor MN1, and while dropping to the transition voltage lower than inverter 208, the reset signal SR1 output that inverter 208 is exported will transfer high-voltage level again to, thereby makes power supply reset circuit 300 can have the power down detecting function of supply voltage VDD.
In sum, the discharge path that the present invention provides by discharge cell, rapidly the voltage of the input of inverter is pulled low to ground voltage level, to guarantee that reset signal can correctly be produced, reduce the impact of power supply rise/fall speed on power supply reset circuit output reset signal, avoid causing system to work as machine or undesired, also can detect in addition the rapid drawdown situation of supply voltage.
Although the present invention discloses as above with embodiment; so it is not in order to limit the present invention; technical staff in technical field under any; without departing from the spirit and scope of the present invention; when doing a little change and retouching, therefore protection scope of the present invention is when being as the criterion depending on the appended claim scope of the applying for a patent person of defining.
Claims (10)
1. a power supply reset circuit, comprising:
One inverter;
One voltage control unit, is coupled between a supply voltage and the input of this inverter, closes the voltage transmission path between the input of this supply voltage and this inverter according to this supply voltage;
One electric capacity, is coupled between the input and a ground connection of this inverter; And
One discharge cell, is coupled between the input and this ground connection of this inverter, provides a discharge path, and make the voltage of the input of this inverter be down to the voltage level of this ground connection in the time that this supply voltage declines.
2. power supply reset circuit as claimed in claim 1, wherein when this supply voltage is during lower than a predeterminated voltage, this voltage control unit is closed the voltage transmission path between the input of this supply voltage and this inverter.
3. power supply reset circuit as claimed in claim 2, wherein this voltage control unit comprises:
One the first transistor, its grid and drain electrode couple this supply voltage, and the source electrode of this first transistor couples the input of this inverter.
4. power supply reset circuit as claimed in claim 3, the critical voltage that wherein this predeterminated voltage is this first transistor.
5. power supply reset circuit as claimed in claim 1, wherein this discharge cell comprises:
One resistance, is coupled between the input and this ground connection of this inverter.
6. power supply reset circuit as claimed in claim 5, wherein this resistance is polysilicon resistance, diffusion resistance or vague and general type metal-oxide semiconductor transistor.
7. power supply reset circuit as claimed in claim 1, wherein this inverter is anti-phase Schmidt trigger.
8. power supply reset circuit as claimed in claim 1, also comprises:
One current limliting unit, is coupled between this supply voltage and this voltage control unit, flows to the size of current of this voltage control unit in order to restriction.
9. power supply reset circuit as claimed in claim 8, wherein this current limliting unit comprises:
One transistor seconds, its grid couples this ground connection, and the source electrode of this transistor seconds is coupled to this supply voltage, and the drain electrode of this transistor seconds couples this voltage control unit.
10. power supply reset circuit as claimed in claim 8, wherein this current limliting unit comprises:
One current-limiting resistance, is coupled between this supply voltage and this voltage control unit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW101138956A TW201417497A (en) | 2012-10-22 | 2012-10-22 | Power on reset circuit |
| TW101138956 | 2012-10-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103780235A true CN103780235A (en) | 2014-05-07 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210424947.6A Pending CN103780235A (en) | 2012-10-22 | 2012-10-30 | Power supply reset circuit |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN103780235A (en) |
| TW (1) | TW201417497A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112290931A (en) * | 2020-12-07 | 2021-01-29 | 南京元络芯科技有限公司 | Compound semiconductor-based logic control circuit |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI504143B (en) * | 2012-12-11 | 2015-10-11 | Princeton Technology Corp | Power on reset circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030201807A1 (en) * | 2000-03-29 | 2003-10-30 | Mitsubishi Denki Kabushiki Kaisha | Power on reset circuit |
| CN101030774A (en) * | 2006-02-28 | 2007-09-05 | 盛群半导体股份有限公司 | Circuit and method for generating power-supply initial reset signal |
| CN201421585Y (en) * | 2009-03-19 | 2010-03-10 | 鸿富锦精密工业（深圳）有限公司 | Reset signal generating circuit |
| CN201830221U (en) * | 2010-10-13 | 2011-05-11 | 四川九州电子科技股份有限公司 | Reset control circuit |
| CN102377416A (en) * | 2010-08-06 | 2012-03-14 | 盛群半导体股份有限公司 | Power supply resetting circuit |
-
2012
- 2012-10-22 TW TW101138956A patent/TW201417497A/en unknown
- 2012-10-30 CN CN201210424947.6A patent/CN103780235A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030201807A1 (en) * | 2000-03-29 | 2003-10-30 | Mitsubishi Denki Kabushiki Kaisha | Power on reset circuit |
| CN101030774A (en) * | 2006-02-28 | 2007-09-05 | 盛群半导体股份有限公司 | Circuit and method for generating power-supply initial reset signal |
| CN201421585Y (en) * | 2009-03-19 | 2010-03-10 | 鸿富锦精密工业（深圳）有限公司 | Reset signal generating circuit |
| CN102377416A (en) * | 2010-08-06 | 2012-03-14 | 盛群半导体股份有限公司 | Power supply resetting circuit |
| CN201830221U (en) * | 2010-10-13 | 2011-05-11 | 四川九州电子科技股份有限公司 | Reset control circuit |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112290931A (en) * | 2020-12-07 | 2021-01-29 | 南京元络芯科技有限公司 | Compound semiconductor-based logic control circuit |
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| Publication number | Publication date |
|---|---|
| TW201417497A (en) | 2014-05-01 |
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| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20140507 |