CN103580459A - Integratable power filter - Google Patents
Integratable power filter Download PDFInfo
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- CN103580459A CN103580459A CN201210270092.6A CN201210270092A CN103580459A CN 103580459 A CN103580459 A CN 103580459A CN 201210270092 A CN201210270092 A CN 201210270092A CN 103580459 A CN103580459 A CN 103580459A
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- switch
- electric capacity
- impedance unit
- power
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Abstract
The invention provides an integratable power filter which comprises at least one impedance unit connected with a power output end and a second capacitor connected with the impedance units through switches. Each impedance unit comprises one switch and at least one first capacitor, the switches are turned on and off according to preset frequency, and the first capacitors are controlled to be charged by the switches. The first capacitors of a farad magnitude are used in a power filter circuit to form a resistor of a more than hundred-megamega magnitude, and the area occupied by the resistor in the filter chip can be greatly reduced.
Description
Technical field
The present invention relates to a kind of filter, particularly relate to a kind of power-supply filter that can be integrated.
Background technology
The size of electronic product is along with development that can integrated circuit is done less and less, so electronic product is more and more higher to the stability requirement of the voltage of power supply output, low especially, in micro-microphone field, the bias voltage that power supply provides directly affects the job stability of micro-microphone, therefore, need to provide a filter circuit at micro-microphone power output end.At present, conventional filter circuit is RC circuit, and wherein, the resistance of resistance is 100,000,000 above magnitudes, and this is for the more and more less integrated circuit of size, and 100,000,000 grades of shared sizes of other resistance are difficult to meet the dimensional requirement of the filter in integrated circuit.In order to solve the size of integrated circuit, the less filter circuit of size that filter that can be integrated has also adopted diode and electric capacity to form, yet, because diode component itself exists noise, therefore, the filter effect of the filter circuit that each comprises diode is subject to the impact of diode component, cannot guarantee that batch production filter out all meets the requirements.
Therefore, need to can improve by integrated power-supply filter existing, to provide, reliability is high, the power-supply filter of good stability.
Summary of the invention
The shortcoming of prior art, the object of the present invention is to provide a kind of power-supply filter that can be integrated in view of the above, to provide, reliability is high, the power-supply filter of good stability.
For achieving the above object and other relevant objects, the invention provides a kind of power-supply filter that can be integrated, it comprises: the impedance unit that at least one is connected with power output end, wherein, described impedance unit comprises that one is subject to described switch to control the first electric capacity of charging by the open/close switch of predeterminated frequency and at least one; The second electric capacity being connected with described impedance unit by described switch; Adjacent described switch is alternately open/close.
Preferably, described impedance unit comprises: one by the open/close switch of predeterminated frequency and a plurality of the first electric capacity that is subject to described switch to control the series connection/parallel connection of charging.
Preferably, described impedance unit is a plurality of, and is connected to one by one described power output end.
Preferably, described impedance unit is a plurality of and is connected to one by one described power output end, and wherein, described in each, impedance unit comprises that one by the open/close switch of predeterminated frequency and first electric capacity that is subject to described switch to control charging.
Preferably, adjacent described switch is alternately open/close by default separately frequency.
The described switch of preferably, being separated by act in agreement and the step of adjacent described switch contrary.
Preferably, all described switches are according to identical frequency but different step is carried out open/close.
Preferably, the open/close frequency of described switch is greater than 20KHz.
Preferably, the capacitance of described the first electric capacity is in Flying Farah magnitude.
As mentioned above, power-supply filter that can be integrated of the present invention, has following beneficial effect: utilize described first electric capacity of a plurality of Flying Farah magnitudes to form resistance more than 100,000,000 magnitudes, can greatly reduce resistance shared area in filter chip; In addition, adopt described the first electric capacity to form the high resistance measurement in filter, be conducive to reduce the noise that element itself produces; In addition, only adopt described switch and described the first electric capacity to form the impedance unit in filter circuit, greatly reduce the manufacture difficulty of integrated filter, be conducive to be applied in microcircuit; Also have, the frequency of described switch, more than 20kHz, can be avoided the impact of described switch on voice signal.
Accompanying drawing explanation
Fig. 1 is shown as the circuit diagram of power-supply filter that can be integrated of the present invention.
Fig. 2 is shown as the circuit diagram of a kind of preferred version of power-supply filter that can be integrated of the present invention.
Fig. 3 is shown as the circuit diagram of another preferred version of power-supply filter that can be integrated of the present invention.
Fig. 4 is shown as the circuit diagram of another preferred version of power-supply filter that can be integrated of the present invention.
Element numbers explanation
1 power-supply filter
11 impedance units
111 switches
112 first electric capacity
12 second electric capacity
2 power supplys
Embodiment
By particular specific embodiment explanation embodiments of the present invention, person skilled in the art scholar can understand other advantages of the present invention and effect easily by the disclosed content of this specification below.
Refer to Fig. 1 to Fig. 4.Notice, appended graphic the illustrated structure of this specification, ratio, size etc., equal contents in order to coordinate specification to disclose only, for person skilled in the art scholar, understand and read, not in order to limit the enforceable qualifications of the present invention, therefore the technical essential meaning of tool not, the adjustment of the modification of any structure, the change of proportionate relationship or size, not affecting under the effect that the present invention can produce and the object that can reach, all should still drop on disclosed technology contents and obtain in the scope that can contain.
Embodiment mono-
Fig. 1 is shown as the structural representation of power-supply filter that can be integrated of the present invention.Described power-supply filter 1 comprises: at least one impedance unit 11, the second electric capacity 12.
Described impedance unit 11 is connected with power supply 2 outputs, and it comprises: one is subject to described switch 111 to control the first electric capacity 112 of charging by the open/close switch 111 of predeterminated frequency and at least one.Wherein, described power supply 2 comprises anyly can produce the power supply of bigoted voltage for acoustic-electric device, and it includes but not limited to charge pump etc.The quantity of described impedance unit 11 can be one, can be also a plurality of, and when described impedance unit 11 is while being a plurality of, described in each, impedance unit 11 is one by one connected in the output of described power supply 2.Preferably, the resistance value that all described impedance units 11 form is greater than 1G Ω.The quantity of described the first electric capacity 112 can be one, can be also a plurality of.The capacitance of described the first electric capacity 112 is preferably Flying Farah magnitude.Described switch 111 comprises anyly can carry out open/close switch according to default frequency, and it includes but not limited to controlled xtal pipe switch etc.Described predeterminated frequency is preferably more than 20kHz.For example, described switch 111 subject clock signals carry out open/close.
Described the second electric capacity 12 is connected with described impedance unit by described switch 111, for filtering high-frequency electric wave.Wherein, adjacent described switch is alternately open/close.The capacitance of described the second electric capacity 12 is preferably in picofarad magnitude, to filter high-frequency noise.
Wherein, adjacent described switch 111 replaces open/close mode and includes but not limited to:
1) all described switches 111 are according to identical frequency but different step is carried out open/close.For example, as shown in Figure 3, the frequency of the described switch 111 in all described impedance units 11 is 40kHz, and the described switch 111 in three described impedance units 11 is open/close one by one in a time cycle 0.25ms, with different step, carries out open/close.
2) the described switch 111 of being separated by act in agreement and adjacent described switch 111 steps contrary.For example, as shown in Figure 3, the frequency of the described switch 111 in all described impedance units 11 is identical, from described power output end, the described switch 111 of first and third all carries out open/closely first to open the step of closing afterwards, and 111 steps with make-before-break of described switch of second, four are carried out open/close.
Particularly, described impedance unit 11 is one, and it comprises: one by the open/close switch 111 of predeterminated frequency and a plurality of the first electric capacity 112 that is subject to described switch to control the series connection of charging.
For example, as shown in Figure 2, one end of described switch 111 in described impedance unit 11 connects described power supply 2 outputs, the other end connects described first electric capacity 112 of 5 series connection, the other end ground connection of described first electric capacity 112 of these 5 series connection, wherein, described in each, the capacitance of the first electric capacity 112 is 100fF, the switching frequency of described switch 111 is 40kHz, the total capacitance value of described the first electric capacity 112 that can these 5 series connection by formula (1) is 20fF, then, by formula (2), obtain the quantity of electric charge that described first electric capacity 112 of series connection shifts in 111 1 switching cycles at described switch, this quantity of electric charge also equals the product in electric current and a described switching cycle, as formula (3), then, the resistance that formula (3) substitution formula (4) is obtained to described impedance unit 11 equals the total capacitance value of described the first electric capacity 112 and the inverse of described switch 111 frequency product of connecting, the total resistance that obtains described impedance unit 11 is 1.25G Ω.
1/C=1/C
f1+ 1/C
f2+ 1/C
f3+ ... + 1/C
fnformula (1)
Q=C*V formula (2)
It=C*V=> I=CV/t=> I=CVf formula (3)
R=V/I=V/ (CVf)=1/fC formula (4)
Wherein, C is the total capacitance value of the first electric capacity of series connection.
C
ffor the capacitance of described the first electric capacity 112, n is greater than 1 natural number.
Q is the total charge number of described the first electric capacity 112 of series connection.
V is the magnitude of voltage of described power supply 2 outputs.
I is the current value of described impedance unit 11 of flowing through.
T is 111 1 open/close cycles of described switch.
F is the open/close frequency of described switch 111.
R is the resistance value of described first electric capacity 112 of series connection.
As a kind of preferred version, described impedance unit 11 is a plurality of and is connected to one by one described power supply 2 outputs, wherein, described in each, impedance unit 11 all comprises one by the open/close switch 111 of predeterminated frequency and a plurality of described the first electric capacity 112 that is subject to described switch to control the series connection/parallel connection of charging, described the second electric capacity 12 is connected with described impedance unit by described switch 111, wherein, adjacent described switch 111 is alternately open/close.
As shown in Figure 3, described power-supply filter 1 comprises described impedance unit a1, a2 and a3, described impedance unit al one end is connected with power supply 2 outputs, the other end connects described impedance unit a2, the described impedance unit a2 other end connects described impedance unit a3, described the second electric capacity 12 of switch 111 connection that the other end of described impedance unit a3 opens and closes by pressing predeterminated frequency.Wherein, described in each, impedance unit 11 comprises a described switch 111 and is subject to described switch to control described first electric capacity 112 of 2 series connection of charging.In this example, described in each, the capacitance of the first electric capacity 112 is 200fF, described in each, the frequency of switch 111 is 40kHz, utilizing formula (1) to formula (4) can obtain the resistance R of impedance unit 11 described in each is 0.25G Ω, because adjacent described switch 111 is alternately open/close, three described impedance units 11 are equivalent to 3 series resistances, therefore total resistance of three described impedance units 11 is 3*R=0.75G Ω.
It should be noted that, those skilled in the art should understand that, the capacitance of described the first electric capacity 112 in above-mentioned a plurality of described impedance unit 11 is only for giving an example, but not limitation of the present invention, in fact, in each impedance unit 11, the capacitance of the first electric capacity 112 may not be necessarily identical described in each, and the quantity of described the first electric capacity 112 described in each in impedance unit 11 also may not be identical, can select according to actual conditions.
Also it should be noted that, it should be appreciated by those skilled in the art that a plurality of described the first electric capacity 112 in impedance unit 11 described above also can be in parallel, its resistance is calculated according to formula (5), formula (3), formula (4), is not described in detail in this.
C ' C '
f1+ C '
f2+ ... + C '
fnformula (5)
Wherein, C ' is the total capacitance value of the first electric capacity of parallel connection.
C '
ffor the capacitance of described the first electric capacity 112, n is greater than 1 natural number.
As another preferred version, described power-supply filter 1 comprises a plurality of described impedance units 11, and is connected to one by one described power supply 2 outputs, described the second electric capacity 12 of switch 111 connection that described in last, impedance unit 11 opens and closes by pressing predeterminated frequency.Wherein, described in each, impedance unit 11 comprises a described switch 111 and described first electric capacity 112 that is subject to described switch 111 control chargings, and wherein, adjacent described switch 111 is alternately open/close.
It should be noted that, those skilled in the art should understand that, described switch 111 in above-mentioned adjacent described impedance unit 11 replaces open/close mode and described switch 111 in adjacent described impedance unit 11 in embodiment mono-by default separately frequency, and by default separately frequency, to replace open/close mode identical or close, therefore be not described in detail in this.
For example, as shown in Figure 4, in described power-supply filter 1, comprise 6 described impedance units 11 that are connected to one by one described power supply 2 outputs, described the second electric capacity 12 of switch 111 connection that described in last, impedance unit 11 opens and closes by pressing predeterminated frequency, described in each, impedance unit 11 comprises a described switch 111 and described first electric capacity 112 that is subject to described switch 111 control chargings.Wherein, the frequency of described switch 111 is 40kHz, the capacitance of described the first electric capacity 112 is 100fF, utilizing formula (1) to formula (4) can obtain the resistance R of impedance unit 11 described in each is 0.25G Ω, because the described switch 111 in these 6 described impedance units 11 is alternately open/close, these 6 described impedance units 11 are equivalent to 6 series resistances, therefore total resistance of 6 described impedance units 11 is 6*R=1.5G Ω.
It should be noted that, those skilled in the art should understand that, the capacitance of described the first electric capacity 112 in above-mentioned a plurality of impedance unit 11 is only for giving an example, but not limitation of the present invention, in fact, in each impedance unit 11, the capacitance of the first electric capacity 112 may not be necessarily identical described in each, and the quantity of the first electric capacity 112 also may not be identical described in each described in each in impedance unit 11, can select according to actual conditions.
In sum, power-supply filter that can be integrated of the present invention, utilizes described first electric capacity of a plurality of Flying Farah magnitudes to form the resistance of G magnitude, can greatly reduce filter resistor shared area in chip; In addition, adopt described the first electric capacity to form the high resistance measurement in filter, be conducive to reduce the noise that element itself produces; In addition, only adopt described switch and described the first electric capacity to form the impedance unit in filter circuit, greatly reduce the manufacture difficulty of integrated filter, be conducive to be applied in microcircuit; Also have, the frequency of described switch, more than 20kHz, can be avoided the impact of described switch on voice signal.So the present invention has effectively overcome various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all can, under spirit of the present invention and category, modify or change above-described embodiment.Therefore, such as in affiliated technical field, have and conventionally know that the knowledgeable, not departing from all equivalence modifications that complete under disclosed spirit and technological thought or changing, must be contained by claim of the present invention.
Claims (8)
1. a power-supply filter that can be integrated, is characterized in that, at least comprises:
The impedance unit that at least one is connected with power output end, wherein, described impedance unit comprises that one is subject to described switch to control the first electric capacity of charging by the open/close switch of predeterminated frequency and at least one;
The second electric capacity being connected with described impedance unit by described switch;
Wherein, adjacent described switch is alternately open/close.
2. power-supply filter that can be integrated according to claim 1, is characterized in that, described impedance unit comprises: one by the open/close switch of predeterminated frequency and a plurality of the first electric capacity that is subject to described switch to control the series connection/parallel connection of charging.
3. power-supply filter that can be integrated according to claim 2, is characterized in that, described impedance unit is a plurality of, and is connected to one by one described power output end.
4. power-supply filter that can be integrated according to claim 1, it is characterized in that, described impedance unit is a plurality of and is connected to one by one described power output end, wherein, described in each, impedance unit comprises that one by the open/close switch of predeterminated frequency and first electric capacity that is subject to described switch to control charging.
5. power-supply filter that can be integrated according to claim 1, is characterized in that, the described switch of being separated by act in agreement and the step of adjacent described switch contrary.
6. power-supply filter that can be integrated according to claim 1, is characterized in that, all described switches are according to identical frequency but different step is carried out open/close.
7. power-supply filter that can be integrated according to claim 1, is characterized in that, the open/close frequency of described switch is greater than 20KHz.
8. power-supply filter that can be integrated according to claim 1, is characterized in that, the capacitance of described the first electric capacity is in Flying Farah magnitude.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210270092.6A CN103580459A (en) | 2012-07-31 | 2012-07-31 | Integratable power filter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210270092.6A CN103580459A (en) | 2012-07-31 | 2012-07-31 | Integratable power filter |
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| Publication Number | Publication Date |
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| CN103580459A true CN103580459A (en) | 2014-02-12 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201210270092.6A Pending CN103580459A (en) | 2012-07-31 | 2012-07-31 | Integratable power filter |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1077800A (en) * | 1991-12-26 | 1993-10-27 | 日本电气株式会社 | Time constant detecting circuit and time constant adjusting circuit |
| US20100090758A1 (en) * | 2008-10-10 | 2010-04-15 | Lu Rui-Hong | low-pass filter |
| CN202798438U (en) * | 2012-07-31 | 2013-03-13 | 无锡市葆灵电子科技有限公司 | Integratable power filter |
-
2012
- 2012-07-31 CN CN201210270092.6A patent/CN103580459A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1077800A (en) * | 1991-12-26 | 1993-10-27 | 日本电气株式会社 | Time constant detecting circuit and time constant adjusting circuit |
| US20100090758A1 (en) * | 2008-10-10 | 2010-04-15 | Lu Rui-Hong | low-pass filter |
| CN202798438U (en) * | 2012-07-31 | 2013-03-13 | 无锡市葆灵电子科技有限公司 | Integratable power filter |
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Application publication date: 20140212 |