CN101739054B - Active current limiting circuit and power supply regulator using same - Google Patents
Active current limiting circuit and power supply regulator using same Download PDFInfo
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- CN101739054B CN101739054B CN2008101618966A CN200810161896A CN101739054B CN 101739054 B CN101739054 B CN 101739054B CN 2008101618966 A CN2008101618966 A CN 2008101618966A CN 200810161896 A CN200810161896 A CN 200810161896A CN 101739054 B CN101739054 B CN 101739054B
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Abstract
The invention mainly discloses a current limiting circuit, namely, an over-current protection (OCP) circuit and a power supply regulator using the same, and aims to protect a power component and a load circuit. The traditional current limiting circuit converts detected overcurrent to voltage by using a resistor and a field effect transistor, and then opens a P-type transistor, so that a charging current clamps grid voltage of a power transistor to fulfill the aim of limiting the current. However, the process changes of the resistor and the field effect transistor and the temperature characteristic per se of the component often cause considerable error of current limiting. Therefore, the accuracy of the current limiting circuit is improved in a current comparison mode.
Description
Technical field
The present invention is for a kind of current limit circuit and use the power regulator of this circuit, in particular to a kind of active mode current restricting circuits and use the power regulator of this circuit.
Background technology
Generally speaking; In the dc voltage stabilizer application of (being called power regulator power regulator again); There are some holding circuits in the capital; And these holding circuits have overvoltage protection, over-temperature protection and overcurrent protection, and wherein overcurrent protection can utilize a current limit circuit (current limiting circuit) to realize.The electric current that the mechanism of electric current restriction the most often utilizes the detection power transistor to be flow through; Utilize a resistance that detected current conversion is become voltage; And this voltage is again with a P transistor npn npn conducting; Make a charging current that the grid voltage of power transistor is lived to strangulation, so can limit the load current of dc voltage changer, reach the protection of excess current.
Traditional method such as Fig. 1 and shown in Figure 2.Fig. 1 is a U.S. Patent number 7,362, the prior art of 080 current limit circuit, the resistance R in (figure one)
S100, power transistor M is flow through in detection
101Electric current, and this current conversion become voltage, come oxide-semiconductor control transistors M
102When excess current takes place, R
S100On the enough opening M of pressure drop
102, have a charging current with M this moment
101Grid voltage (VEO) live to strangulation, so just reached the purpose of current limliting.But, the disadvantage of the practice like this can increase the minimum voltage difference (dropout voltage) of Voltagre regulator input-output voltage exactly.
Fig. 2 is a U.S. Patent number 7,362,080 propose the improvement after framework, then be to utilize transistor M
P203Come detection power transistor M
P201Electric current, when the situation of excess current takes place when, resistance R
S201On pressure drop be enough to let transistor M
P204Conducting, have a charging current with this M this moment
P201Grid voltage live to strangulation, reach the effect of current limliting identically.But, this resistance R
S201To the error that technology and temperature variations caused, will directly influence the precision of current limit circuit.
In addition, Fig. 1 and Fig. 2 prior art all use resistance, if will electric current be limited in lower value, certainly will will increase resistance value, so will increase area of chip.Comprehensive above-mentioned explanation, the precision of current limliting with the efficient use of chip area (areaefficiency), is emphasis of the present invention under raising different process and the temperature variation.
Therefore; The inventor of this case works out a kind of current limit circuit and uses the power regulator of this circuit; In particular to a kind of active mode current restricting circuits and use the power regulator of this circuit, it can improve in the prior art for different process and the big present situation of temperature variation.
Summary of the invention
Power regulator and method of operating thereof that technical matters to be solved by this invention is that a kind of active mode current restricting circuits is provided and uses this circuit, it utilizes driving component to form feedback circuit, and then the purpose of low technology of the high precision of reaching and temperature variations.
Preferable, the present invention includes a kind of current limiting method in power regulator, it comprises at least:
(a) beginning;
(b) power regulator is exported a fixed voltage and power transistor down at normal voltage stabilizing state provides an electric current to load;
(c) sense power the transistor output current excessive or electric current that is short-circuited whether if not, is got back to a step (b); If arrive next step (d);
(d) start active overcurrent limiting circuit; And
(e) whether over-current condition removes, and if not, gets back to a step (d); If get back to (b).
Preferable, this power regulator, it comprises at least:
One P type power transistor, its source electrode receive unadjusted first voltage source and produce second voltage that is conditioned according to a control signal in drain electrode;
One feedback circuit, it produces a feedback signal via the dividing potential drop to this second voltage;
One differential amplifier, its output is coupled to the grid of this power transistor, and its positive input terminal is coupled to this feedback signal, and its negative input end is coupled to a reference voltage;
One holding circuit, this holding circuit are to limit first electric current of this P type power transistor of flowing through by configuration, and when first electric current surpasses a predetermined value, improve the voltage of the grid of this this power transistor; Wherein, this holding circuit comprises a plurality of transistors and does not comprise resistance.
Preferable, the present invention addresses a kind of current limit circuit in power regulator, and it comprises at least:
One P type power transistor, its source-coupled is to this first voltage source;
The DC current mirror, it comprises a pair of N transistor npn npn, and this joins to grid to N transistor npn npn grid, and wherein a N transistor npn npn grid and drain electrode are joined;
The DC current source, wherein this DC current source export a predetermined value direction over the ground electric current and be connected to one first end points mutually with the output of DC current mirror;
One the one P transistor npn npn, its source-coupled are to this first voltage source, and its gate coupled is to this first end points, and its drain coupled is to the grid of this P type power transistor; And
One the 2nd P transistor npn npn, its source-coupled are to this first voltage source, and its gate coupled is to the grid of this P type power transistor, and its drain coupled is to the input end of this DC current mirror.
For further specifying structure purpose of the present invention and effect, cooperate the icon example to specify now as after.
Description of drawings
Fig. 1 is the example schematic of prior art;
Fig. 2 is another example schematic of Prior Art;
Fig. 3 is for being used for method flow diagram of the present invention; And
Fig. 4 is the example schematic that is used for current limit circuit of the present invention; And
Fig. 5 is the example schematic that is used for power regulator of the present invention.
Wherein Reference numeral is:
I
REFElectric current
R
S100R
S202Resistance
M
101M
P201M
401Power transistor
M
102MP
201M
P203MP
204Transistor
M
402～M
406Transistor
501 P type power transistors 501
502 feedback circuits
503 differential amplifiers
504 holding circuits
Embodiment
Please refer to Fig. 3, Fig. 3 is a kind of current limiting method in power regulator of the present invention, and it comprises at least:
(a) beginning;
(b) power regulator is exported a fixed voltage and power transistor down at normal voltage stabilizing state provides an electric current to load;
(c) sense power the transistor output current excessive or electric current that is short-circuited whether if not, is got back to a step (b); If arrive next step (d);
(d) start active overcurrent limiting circuit; And
(e) whether over-current condition removes, and if not, gets back to a step (d); If get back to (b).
Please refer to Fig. 4, Fig. 4 is a preferred embodiment of the present invention, transistor M
401Be a power transistor, transistor M
402～M
406Constitute a current limit circuit, wherein transistor M
405Electric current I
REF, provide by a generating circuit from reference voltage.Its operating principle is following: transistor M
402Detection power transistor M
401On electric current, take place when output load current has the situation of excess current, this moment transistor M
402The electric current that detects will rise, and electric current is through a current mirror M
403With M
404, then with transistor M
405Electric current I
REFCompare, the voltage that is produced is with turn-on transistor M
406, and produce a charging current with M
401Grid voltage (VEO) live to strangulation, so just reached the purpose of restriction electric current.Current limit circuit of the present invention does not have any resistance, thus be called again the active mode current restricting circuits (Active Current LimitingCircuit, ACLC), because do not use resistance, so promoted the utilization rate of chip area yet.
Transistor M
405Electric current I
REF, be to provide by generating circuit from reference voltage, we can design this electric current I
REF, improve electric current I
REFTo the resistivity of technology and temperature variation, cut-off current precision of the present invention like this also will promote widely.
Fig. 5 is a kind of power regulator of the present invention, and it comprises at least:
One P type power transistor 501, its source electrode receive unadjusted first voltage source and produce second voltage that is conditioned according to a control signal in drain electrode;
One feedback circuit 502, it produces a feedback signal via the dividing potential drop to this second voltage;
One differential amplifier 503, its output is coupled to the grid of this power transistor 501, and its positive input terminal is coupled to this feedback signal, and its negative input end is coupled to a reference voltage;
One holding circuit 504, this holding circuit 504 are to limit one first electric current of this P type power transistor of flowing through by configuration, and when this first electric current surpasses a predetermined value, improve the voltage of the grid of this this power transistor 501; Wherein, this holding circuit 504 comprises a plurality of transistors and does not comprise resistance.
Wherein, preferable, this feedback circuit 502 further comprises two series resistors.
Wherein, preferable, this holding circuit 504 further comprises the M among DC current source such as Fig. 4
405
Wherein, preferable, this holding circuit 504 further comprises the M among DC current mirror such as Fig. 4
403～404
Wherein, preferable, this holding circuit 504 further comprises:
The DC current mirror, it comprises the M among a pair of N transistor npn npn such as Fig. 4
403～404, this joins to grid to N transistor npn npn grid, and wherein a N transistor npn npn grid and drain electrode are joined;
M among DC current source such as Fig. 4
405, wherein this DC current source export a predetermined value direction over the ground electric current and be connected to one first end points mutually with the output of DC current mirror;
M among one the one P transistor npn npn such as Fig. 4
406, its source-coupled is to this first voltage source, and its gate coupled is to this first end points, the output of its drain coupled to this differential amplifier; And
M among one the 2nd P transistor npn npn such as Fig. 4
402, its source-coupled is to this first voltage source, the output of its gate coupled to this differential amplifier, and its drain coupled is to the input end of this DC current mirror.
Wherein, preferable, this DC current source is formed by at least one P transistor npn npn.
Wherein, preferable, this DC current mirror is the cascade that splices (cascode) current mirror.
Wherein, preferable, the DC current of this DC current source is produced by an energy gap reference circuit (bandgapreference).
Skilled personnel can understand this invention and also can be applicable to power regulator, repeat no more at this.
Though the present invention discloses as above with preferred embodiment; Right its is not in order to limit the present invention; Under the situation that does not deviate from spirit of the present invention and essence thereof; Those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (13)
1. a power regulator is characterized in that, comprises at least:
One P type power transistor, its source electrode receive unadjusted first voltage source and produce second voltage that is conditioned according to a control signal in drain electrode;
One feedback circuit, it produces a feedback signal via the dividing potential drop to this second voltage;
One differential amplifier, its output is coupled to the grid of this power transistor, and its positive input terminal is coupled to this feedback signal, and its negative input end is coupled to a reference voltage;
One holding circuit, this holding circuit are to limit first electric current of this P type power transistor of flowing through by configuration, and when first electric current surpasses a predetermined value, improve the voltage of the grid of this power transistor; Wherein, this holding circuit comprises a plurality of transistors and does not comprise resistance; This holding circuit further comprises:
The DC current mirror, it comprises a pair of N transistor npn npn, and this joins to grid to N transistor npn npn grid, and wherein a N transistor npn npn grid and drain electrode are joined;
The DC current source, wherein this DC current source export a predetermined value direction over the ground electric current and be connected to one first end points mutually with the output of DC current mirror;
One the one P transistor npn npn, its source-coupled are to this first voltage source, and its gate coupled is to this first end points, the output of its drain coupled to this differential amplifier; And
One the 2nd P transistor npn npn, its source-coupled be to this first voltage source, the output of its gate coupled to this differential amplifier, and its drain coupled is to the input end of this DC current mirror.
2. power regulator as claimed in claim 1 is characterized in that, this feedback circuit further comprises two series resistors.
3. power regulator as claimed in claim 1 is characterized in that this holding circuit further comprises the DC current source.
4. power regulator as claimed in claim 1 is characterized in that this holding circuit further comprises the DC current mirror.
5. power regulator as claimed in claim 1 is characterized in that, this DC current source is formed by at least one P transistor npn npn.
6. power regulator as claimed in claim 1 is characterized in that, this DC current mirror is the common-source common-gate current mirror that splices.
7. power regulator as claimed in claim 1 is characterized in that, the DC current of this DC current source is produced by an energy gap reference circuit.
8. the current limit circuit in power regulator is characterized in that, comprises at least:
One P type power transistor, its source-coupled to one first voltage source;
The DC current mirror, it comprises a pair of N transistor npn npn, and this joins to grid to N transistor npn npn grid, and wherein a N transistor npn npn grid and drain electrode are joined;
The DC current source, wherein this DC current source export a predetermined value direction over the ground electric current and be connected to one first end points mutually with the output of DC current mirror;
One the one P transistor npn npn, its source-coupled are to this first voltage source, and its gate coupled is to this first end points, and its drain coupled is to the grid of this P type power transistor; And
One the 2nd P transistor npn npn, its source-coupled are to this first voltage source, and its gate coupled is to the grid of this P type power transistor, and its drain coupled is to the input end of this DC current mirror.
9. current limit circuit as claimed in claim 8 is characterized in that, this DC current source is formed by at least one P transistor npn npn.
10. current limit circuit as claimed in claim 8 is characterized in that, this DC current mirror is the common-source common-gate current mirror that splices.
11. current limit circuit as claimed in claim 8 is characterized in that, the DC current of this DC current source is produced by an energy gap reference circuit.
12. current limit circuit as claimed in claim 8 is characterized in that, this current limit circuit is low technology variation.
13. current limit circuit as claimed in claim 8 is characterized in that, this current limit circuit is the low temperature variation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101618966A CN101739054B (en) | 2008-10-13 | 2008-10-13 | Active current limiting circuit and power supply regulator using same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2008101618966A CN101739054B (en) | 2008-10-13 | 2008-10-13 | Active current limiting circuit and power supply regulator using same |
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| Publication Number | Publication Date |
|---|---|
| CN101739054A CN101739054A (en) | 2010-06-16 |
| CN101739054B true CN101739054B (en) | 2012-02-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2008101618966A Active CN101739054B (en) | 2008-10-13 | 2008-10-13 | Active current limiting circuit and power supply regulator using same |
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Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9793707B2 (en) | 2013-05-28 | 2017-10-17 | Texas Instruments Incorporated | Fast transient precision power regulation apparatus |
| CN104639054B (en) * | 2013-11-06 | 2018-07-03 | 奇景光电股份有限公司 | Overcurrent protection circuit |
| JP6253418B2 (en) * | 2014-01-17 | 2017-12-27 | エスアイアイ・セミコンダクタ株式会社 | Voltage regulator and semiconductor device |
| CN104078966B (en) * | 2014-07-14 | 2018-09-07 | 余姚市劲仪仪表有限公司 | A kind of anti-high tension protection circuit of Low ESR current-limiting type |
| US9787180B2 (en) * | 2014-07-24 | 2017-10-10 | Infineon Technologies Ag | High side switch with current limit feedback |
| JP6520102B2 (en) * | 2014-12-17 | 2019-05-29 | 富士電機株式会社 | Semiconductor device and current limiting method |
| CN105680431B (en) * | 2016-03-25 | 2018-07-20 | 中国电子科技集团公司第五十八研究所 | A kind of adjustable current-limiting protection circuit |
| CN105700598B (en) * | 2016-03-25 | 2017-08-18 | 南京微盟电子有限公司 | A kind of foldback current limit circuit for Voltagre regulator |
| CN106774595A (en) * | 2017-01-09 | 2017-05-31 | 电子科技大学 | A kind of current foldback circuit for low pressure difference linear voltage regulator |
| CN111857222B (en) * | 2020-06-18 | 2022-04-19 | 苏州浪潮智能科技有限公司 | System for power supply voltage regulation |
| CN118092565A (en) | 2021-06-07 | 2024-05-28 | 长江存储科技有限责任公司 | Power leakage blocking in low drop-out regulators |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6522111B2 (en) * | 2001-01-26 | 2003-02-18 | Linfinity Microelectronics | Linear voltage regulator using adaptive biasing |
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- 2008-10-13 CN CN2008101618966A patent/CN101739054B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6522111B2 (en) * | 2001-01-26 | 2003-02-18 | Linfinity Microelectronics | Linear voltage regulator using adaptive biasing |
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| CN101739054A (en) | 2010-06-16 |
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Effective date of registration: 20200803 Address after: Room 202, No.34, guanri Road, phase II, software park, Xiamen City, Fujian Province Patentee after: Core group integrated circuit (Xiamen) Co., Ltd Address before: Hsinchu City, Taiwan, China Patentee before: Holtek Semiconductor Inc. |
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