CN105988032B - Current detection circuit - Google Patents
Current detection circuit Download PDFInfo
- Publication number
- CN105988032B CN105988032B CN201510039771.6A CN201510039771A CN105988032B CN 105988032 B CN105988032 B CN 105988032B CN 201510039771 A CN201510039771 A CN 201510039771A CN 105988032 B CN105988032 B CN 105988032B
- Authority
- CN
- China
- Prior art keywords
- voltage
- power tube
- transistor
- tube
- equal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
A kind of current detection circuit, input current for detection stream overpower pipe, it include: voltage sample circuit, the first input end being connected with the source electrode with the power tube, the second input terminal being connected with the drain electrode of the power tube, and voltage output end, wherein the voltage exported is equal to the power tube drain voltage when the power tube is opened, is equal to the power tube source voltage in power tube shutdown；Low-pass filter circuit receives the voltage that the voltage output end is exported, and exports through filtered voltage signal；Sampling current generation circuit, receive the voltage signal of low-pass filter circuit output, and there is probe tube, wherein, the drain voltage of the probe tube is equal to the voltage signal of low-pass filter circuit output, the grid voltage of source voltage and the probe tube that the source voltage of the probe tube is equal to the power tube is equal to the grid voltage when power tube is opened, therefore flows through the electric current of the probe tube and the average current of the power tube in fixed ratio.
Description
Technical field
The present invention relates to a kind of current detection circuit, espespecially a kind of current detecting electricity for detecting power tube input current
Road.
Background technique
In the design of Switching Power Supply, it is sometimes desirable to obtain average input current.Main electricity in Switching Power Supply at present
It flows there are two types of sampling methods, one is sample resistances of connecting in current path, and one is taken by proportional to switching tube
Sample pipe is sampled.First method precision is higher, but since the introducing of resistance inevitably reduces efficiency, increases into
This.Switch power supply power tube work is in switch state, due to flowing through the discontinuity and high rate of change of power tube current, second
Method is usually used in sampling and flows through the transient current of power tube, and average current due to the speed of circuit and the interference of switch etc. because
Element can not accurately obtain by this method.
In order to avoid reducing efficiency and accurately obtaining average current input, it is necessary to provide a kind of feasible method.
Summary of the invention
In view of the disadvantages of known techniques, the main object of the present invention is that providing one kind is avoided that reduction efficiency,
The current detection circuit of average current input can be accurately obtained simultaneously.
In order to achieve the above object and other purposes, the present invention provide a kind of current detection circuit then, flow through for detecting
The input current of power tube, comprising: voltage sample circuit has the first input end being connected with the source electrode of the power tube, with
The second input terminal and voltage output end that the drain electrode of the power tube is connected, wherein the voltage exported is opened in the power tube
When be equal to the power tube drain voltage, the power tube shutdown when be equal to the power tube source voltage；Low-pass filter circuit receives
The voltage that the voltage output end is exported, and export through filtered voltage signal；Sampling current generation circuit receives the low pass
The voltage signal of filter circuit output, and there is probe tube, wherein the drain voltage of the probe tube is equal to the low-pass filter circuit
The voltage signal of output, the source voltage of the probe tube are equal to the source voltage of the power tube and the grid electricity of the probe tube
Pressure is equal to the grid voltage when power tube is opened, which further includes the first transistor and second transistor；It should
The type of the first transistor and second transistor is identical as the power tube, and the source electrode of the first transistor is first input
End；The source electrode of the second transistor is second input terminal；And the drain electrode of the first transistor and second transistor is linked,
For the voltage output end；And the wherein grid voltage of the first transistor and the same phase of the grid voltage of the power tube, this is second brilliant
The grid voltage of body pipe and the grid voltage reverse phase of the power tube.Therefore the electric current of the probe tube and being averaged for the power tube are flowed through
Electric current is in fixed ratio.
Compared to known techniques, since current detection circuit of the invention is not connected sample resistance, but work is utilized
In the transistor of deep linear zone, source-drain voltage difference with the electric current that flows through linearly the characteristics of, with voltage sample circuit,
The average current to be detected first is converted into average voltage by low-pass filter circuit, then with sampling current generation circuit the average electricity
Pressure is converted into the electric current of probe tube, can calculate the average current to be detected by the electric current of the probe tube, therefore is avoided that reduction effect
Rate, while average current can be accurately obtained, sufficiently address the missing of the prior art.
Detailed description of the invention
Fig. 1 is the basic framework schematic diagram of typical Switching Power Supply.
Fig. 2 is the configuration diagram of current detection circuit of the present invention.
Fig. 3 A is the voltage sample circuit of current detection circuit of the present invention and the configuration diagram of low-pass filter circuit.
Fig. 3 B is the configuration diagram of the sampling current generation circuit of current detection circuit of the present invention.
Fig. 4 is the voltage oscillogram of each port in Fig. 3 A.
Symbol description:
101 power tubes
102 power tubes
103 inductance
104 capacitors
20 voltage sample circuits
21 low-pass filter circuits
22 sampling current generation circuits
201 first input ends
202 second input terminals
203 voltage output ends
211 output ends
221 probe tubes
2010 the first transistors
2020 second transistors
222 transistors
223 operational amplifiers
Specific embodiment
Illustrate embodiments of the present invention by particular specific embodiment below, those skilled in the art can be by this theory
Other advantages and efficacy of the present invention can be easily understood for the bright revealed content of book.The present invention also can be different specific by other
Embodiment is implemented or is applied.
The main purpose of current detection circuit of the present invention is to measure the average current input of Switching Power Supply.Referring to Fig. 1,
Fig. 1 shows a kind of basic framework schematic diagram of typical Switching Power Supply, mainly by P-channel power tube 101, N-channel power tube 102,
Inductance 103 and capacitor 104 are constituted, and in this illustrative framework, the average current input of Switching Power Supply is similar to flow through function
The average current of rate pipe 101, therefore, the average current input for measuring Switching Power Supply, which is equal to, measures being averaged for power tube 101
Electric current.It notes that, the type of power tube 101,102, which is only for example, to be used, and current detection circuit of the present invention is by appropriateness adjustment
Afterwards, it can be used for measuring the power tube including P-channel or N-channel type.
Referring to Fig. 2, Fig. 2 is the configuration diagram of current detection circuit of the present invention.Current detection circuit of the present invention includes
Voltage sample circuit 20, low-pass filter circuit 21 and sampling current generation circuit 22, as described above, measuring the power tube of Fig. 1
101 average current is equal to the average current input for measuring Switching Power Supply.
Fig. 3 A is please referred to, Fig. 3 A is the voltage sample circuit of current detection circuit of the present invention and the framework of low-pass filter circuit
Schematic diagram.As shown, the voltage sample circuit 20 of current detection circuit of the present invention has first input end in an embodiment
201, the second input terminal 202 and voltage output end 203.The wherein source electrode phase of the power tube 101 of first input end 201 and Fig. 1
Connection, the second input terminal 201 are connected with the drain electrode of power tube 101.Voltage output end 203 modulates (Pulse according to pulse width
Width Modulation, PWM) signal modulation, the voltage exported power tube 101 open when be equal to power tube 101 leak
Pole tension is equal to 101 source voltage of power tube when power tube 101 turns off.
In addition, low-pass filter circuit 21 receives the voltage that voltage output end 203 is exported, and exports and pass through in output end 211
Filtered voltage signal.In another embodiment, capacitor appropriate and resistance value can be chosen, makes cutting for low-pass filter circuit 21
Only frequency is less than the operating switch frequency of power tube 101.
Referring to Fig. 4, Fig. 4 is the voltage oscillogram of each port in Fig. 3 A.In an embodiment, Fig. 4 shows that first is defeated
Enter the output end 211 of end 201, the second input terminal 202, voltage output end 203 and low-pass filter circuit 21, the electricity of these ports
Corrugating figure.Wherein, the voltage waveform of first input end 201 is supply voltage VDD, is also equal to the source electrode electricity of power tube 101
Pressure.Second input terminal 201 is equal to the drain voltage of power tube 101.Voltage output end 203 is exported according to the modulation of pwm signal
Voltage power tube 101 open when be equal to 101 drain voltage of power tube, power tube 101 turn off when be equal to 101 source of power tube
Pole tension.Output end 211 is received the voltage that voltage output end 203 exports by low-pass filter circuit 21, and institute is defeated after filtering
Voltage signal out is approximate DC, with the average voltage of 101 source-drain voltage value of power tube, and slightly fluctuate up and down
Curve.
Voltage sample circuit 20 and the purpose of low-pass filter circuit 21 be, using work deep linear zone transistor,
Its source-drain voltage difference and the electric current flowed through linearly the characteristics of, 101 average current of power tube to be detected is converted into
Average voltage.
Fig. 3 B is please referred to, Fig. 3 B is the configuration diagram of the sampling current generation circuit of current detection circuit of the present invention.Such as
Shown in Fig. 3 B, in an embodiment, sampling current generation circuit 22 receives the voltage signal 211 that low-pass filter circuit 21 exports,
And there is probe tube 221, wherein the drain voltage of probe tube 221 is equal to the voltage signal 211 of low-pass filter circuit output 21,
The grid voltage of source voltage and probe tube 221 that the source voltage of probe tube 221 is equal to power tube 101 is equal to power tube
Grid voltage when 101 unlatching.
The purpose of sampling current generation circuit 22 is, as obtained by voltage sample circuit 20 and low-pass filter circuit 21
Average voltage be converted into the electric current of probe tube 221, in this way, if probe tube 221 and power tube 101 are the crystal of same type
Pipe, and the size of power tube 101 is N times of 221 size of probe tube, then the electric current for flowing through probe tube 221, which is equal to, to be flowed through 101 and puts down
1/N times of equal electric current, can extrapolate the average current of power tube 101 by the electric current for flowing through probe tube 221, reach measurement switch
The purpose of the average current input of power supply.
Fig. 3 A is please referred to, as shown in Figure 3A, in an embodiment, voltage sample circuit may also include the first transistor 2010
And second transistor 2020.For example, the type of the first transistor 2010 and second transistor 2020 can be with 101 phase of power tube
Together, and the source electrode of the first transistor 2010 is first input end 201.The source electrode of second transistor 2020 is the second input terminal 202.
And the 1st and the drain electrode of second transistor 2020 be linked, be voltage output end 203.And wherein the first transistor 2010
Grid voltage and power tube 101 the same phase of grid voltage, the grid of the grid voltage of second transistor 2020 and power tube 101
Voltage inversion, and according to the modulation of pwm signal, the voltage that voltage output end 203 is exported is reached with this and is opened in power tube 101
When be equal to 101 drain voltage of power tube, power tube 101 turn off when be equal to 101 source voltage of power tube.
Fig. 3 B is please referred to, as shown in Figure 3B, in an embodiment, sampling current generation circuit 22 may also include transistor
222 and operational amplifier 223 show.The positive input terminal of operational amplifier 223 is connected with the output end 211 of low-pass filter circuit 21,
Negative input end is connected with 221 source electrode of probe tube of P-channel type, the output end of operational amplifier 223 and the grid of transistor 222
It is connected.The drain electrode of probe tube 221 is connected with the source electrode of transistor 222, the source level phase of the source level and power tube 101 of probe tube 221
It even, is power vd D, the driving voltage phase of grid when the grid voltage of probe tube 221 is opened with power tube 101 in the present embodiment
Deng, in the present embodiment be low potential.
Compared to known techniques, since current detection circuit of the invention is not connected sample resistance, but work is utilized
In the transistor of deep linear zone, source-drain voltage difference with the electric current that flows through linearly the characteristics of, with voltage sample circuit,
The average current to be detected first is converted into average voltage by low-pass filter circuit, then with sampling current generation circuit the average electricity
Pressure is converted into the electric current of probe tube, can calculate the average current to be detected by the electric current of the probe tube, therefore is avoided that reduction effect
Rate, while average current can be accurately obtained, sufficiently address the missing of the prior art.In addition, other advantages of the invention
It is, additional sampling device is not introduced on high current access, it is stronger to the resistivity of switch interference, to operation amplifier
The requirement of device speed is low, and circuit is simple.
By the description of the above preferred embodiment, one skilled in the art is of the invention when can more understand
Feature and spirit, only above-described embodiment only illustrates the principle of the present invention and its effect, rather than to limit the present invention.Therefore,
The modification and variation that any pair of above-described embodiment carries out are without departing from spirit of the invention, and interest field of the invention should be as rear
Listed by the claim stated.
Claims (6)
1. a kind of current detection circuit, the input current for detection stream overpower pipe, which is characterized in that the current detection circuit
Include:
Voltage sample circuit with first input end, the second input terminal and has voltage output end, wherein the first input end
It is connected with the source electrode of the power tube, which is connected with the drain electrode of the power tube, which is exported
Voltage the power tube open when be equal to the power tube drain voltage, the power tube shutdown when be equal to the power tube source electricity
Pressure；
Low-pass filter circuit receives the voltage that the voltage output end is exported, and exports through filtered voltage signal；And it takes
Sample current generating circuit receives the voltage signal of low-pass filter circuit output, and has probe tube, wherein the probe tube
Drain voltage is equal to the voltage signal of low-pass filter circuit output, and the source voltage of the probe tube is equal to the source electrode of the power tube
The grid voltage of voltage and the probe tube is equal to the grid voltage when power tube is opened；
The voltage sample circuit further includes the first transistor and second transistor；
The type of the first transistor and second transistor is identical as the power tube, and the source electrode of the first transistor be this first
Input terminal；The source electrode of the second transistor is second input terminal；And the drain electrode phase of the first transistor and second transistor
Link, for the voltage output end；And the wherein grid voltage of the first transistor and the same phase of the grid voltage of the power tube, this
The grid voltage of two-transistor and the grid voltage reverse phase of the power tube.
2. current detection circuit according to claim 1, which is characterized in that the power tube is P-channel or N-channel type crystal
Pipe.
3. current detection circuit according to claim 2, which is characterized in that the probe tube be and the power tube same type
Transistor.
4. current detection circuit according to claim 1, which is characterized in that the power tube is applied to switching power circuit
In.
5. current detection circuit according to claim 1, which is characterized in that the cutoff frequency of the low-pass filter circuit is less than
The operating switch frequency of the power tube.
6. current detection circuit according to claim 1, which is characterized in that the sampling current generation circuit further includes crystal
Pipe and operational amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510039771.6A CN105988032B (en) | 2015-01-27 | 2015-01-27 | Current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510039771.6A CN105988032B (en) | 2015-01-27 | 2015-01-27 | Current detection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105988032A CN105988032A (en) | 2016-10-05 |
| CN105988032B true CN105988032B (en) | 2019-01-29 |
Family
ID=57034700
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510039771.6A Active CN105988032B (en) | 2015-01-27 | 2015-01-27 | Current detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105988032B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110261661B (en) * | 2019-04-18 | 2022-06-14 | 矽力杰半导体技术(杭州)有限公司 | Current detection circuit and power converter |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE338377T1 (en) * | 2001-09-26 | 2006-09-15 | Dialog Semiconductor Gmbh | MOS CURRENT DETECTION CIRCUIT |
| US20040212421A1 (en) * | 2003-02-25 | 2004-10-28 | Junichi Naka | Standard voltage generation circuit |
| US7557557B2 (en) * | 2004-03-03 | 2009-07-07 | Rohm Co., Ltd. | Current detection circuit, load drive circuit, and memory storage |
| JP2006322711A (en) * | 2005-05-17 | 2006-11-30 | Fuji Electric Device Technology Co Ltd | Voltage detection circuit and current detection circuit |
| CN200956042Y (en) * | 2006-08-25 | 2007-10-03 | 徐海承 | High-end current detecting circuit |
| CN201159747Y (en) * | 2008-02-03 | 2008-12-03 | 深圳艾科创新微电子有限公司 | Inductor current sensing circuit for switch power source |
| CN101963629A (en) * | 2009-07-24 | 2011-02-02 | 瑞萨电子(中国)有限公司 | Current detection device and method |
| CN101666824B (en) * | 2009-10-14 | 2011-07-06 | 美芯晟科技（北京）有限公司 | High-side current detection circuit |
-
2015
- 2015-01-27 CN CN201510039771.6A patent/CN105988032B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN105988032A (en) | 2016-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103954821B (en) | A kind of ripple voltage detection method of filter capacitor equivalent series resistance | |
| CN101029910B (en) | Current inspecting circuit and device | |
| CN103560760B (en) | Amplifying circuit and measuring device | |
| CN205961068U (en) | D class audio amplifier device | |
| US20130271216A1 (en) | High Side Current Sense Amplifier | |
| CN105811765A (en) | Voltage clamping circuit for on-line measurement of conduction voltage drop of power transistor | |
| CN102331517A (en) | Inductive current detection circuit and DC-DC (direct current to direct current) power switch converter | |
| CN105357814B (en) | A kind of peak current detection circuit and method for constant current driver circuit for LED | |
| CN208353304U (en) | Current sense amplifier and general-purpose serial bus USB port | |
| CN103248226B (en) | The switch power controller of average current lag mode | |
| CN105988032B (en) | Current detection circuit | |
| CN102981032A (en) | Detection circuit for whole inductive current waveform and method for detecting whole inductive current waveform | |
| CN103487658B (en) | The testing circuit of high terminal voltage bootstrap N-type switch conduction resistance | |
| CN204347111U (en) | Alternating current sample circuit | |
| CN104020339B (en) | A kind of programmable current testing circuit | |
| CN206339589U (en) | Current detection circuit | |
| CN103941144B (en) | A kind of reference voltage source electric-leakage detection circuit | |
| CN104897943A (en) | High-sensitivity low-power current detection circuit | |
| CN109839980A (en) | A kind of configurable constant-current source circuit of bipolar great power | |
| CN205176715U (en) | Adopt CT to replace voltage control current source circuit of electric current sensing resistance | |
| CN104122437B (en) | Silicon substrate power detector | |
| CN105278599A (en) | Voltage-controlled current source circuit using CT to replace current sensing resistor | |
| CN102706931B (en) | Biasing and non-biasing operating circuit of electrochemical gas sensor and biasing configuration circuit | |
| CN202599895U (en) | Bias voltage and non bias voltage operating circuit of electrochemistry gas sensor and bias voltage configuration circuit | |
| CN204439702U (en) | Inverter type welder current sampling circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CP02 | Change in the address of a patent holder |
Address after: 226017 No. 16 Wei14 Road, Sutong Science and Technology Industrial Park, Nantong City, Jiangsu Province Patentee after: Dioo Microelectronic Co., Ltd. Address before: 201103 Hongqiao International Business Plaza Building 603, 2679 Hechuan Road, Minhang District, Shanghai Patentee before: Dioo Microelectronic Co., Ltd. |
|
| CP02 | Change in the address of a patent holder | ||
| CP03 | Change of name, title or address |
Address after: No.16, wei14 Road, Sutong science and Technology Industrial Park, Nantong, Jiangsu Province Patentee after: Jiangsu Dior Microelectronics Co., Ltd Address before: 226017 Nantong science and Technology Industrial Park, Su Tong Road, Jiangsu, No. 14, No. 16 Patentee before: DIAO MICROELECTRONICS Co.,Ltd. |
|
| CP03 | Change of name, title or address | ||
| CP02 | Change in the address of a patent holder |
Address after: 6 / F, building 8, Zilang science and Technology City, Nantong Innovation Zone, 60 Chongzhou Avenue, Nantong City, Jiangsu Province 226000 Patentee after: Jiangsu Dior Microelectronics Co., Ltd Address before: No.16, wei14 Road, Sutong science and Technology Industrial Park, Nantong, Jiangsu Province Patentee before: Jiangsu Dior Microelectronics Co., Ltd |
|
| CP02 | Change in the address of a patent holder |