CN104635050B - Impedance detection apparatus and method - Google Patents
Impedance detection apparatus and method Download PDFInfo
- Publication number
- CN104635050B CN104635050B CN201310555107.8A CN201310555107A CN104635050B CN 104635050 B CN104635050 B CN 104635050B CN 201310555107 A CN201310555107 A CN 201310555107A CN 104635050 B CN104635050 B CN 104635050B
- Authority
- CN
- China
- Prior art keywords
- impedance
- signal
- detection
- output
- comparative result
- 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 impedance detection apparatus and method, can detect the impedance value of a load.One embodiment of the impedance detection device is included：One AC signal generating circuit, for providing an AC signal；One output buffer, for producing an output voltage and an output current according to the AC signal and an impedance value for loading；One current mirror, for producing an image current according to the output current；One detection impedance, for producing a detection voltage according to the image current；One clock pulse generating circuit, for providing a clock pulses；One comparison circuit, for comparing the output voltage with the detection voltage to produce a comparative result according to the clock pulses；And one control circuit, couple at least one of the comparison circuit and the current mirror and detection impedance, for adjusted according to the comparative result ratio of the image current and the output current and the impedance value of the detection impedance at least one, until the comparative result, to meet one pre-conditioned.The present invention is avoided that abnormal sound.
Description
Technical field
The present invention relates to detection means and method, more particularly to impedance detection apparatus and method.
Background technology
Many existing consumer electronic devices can all provide one or more audio output holes, with external one or more sound
Output device, such as all types of earphones and loudspeaker etc..However, the voice output of different size is for identical sound
Signal can produce different output effects, namely same voice signal via loudspeaker export may volume it is moderate, but via
Earphone output is then deafening；Or same voice signal when being exported by the earphone of a certain type it is melodious it is suitable listen, but by another
The earphone of type but constrains distortion when exporting.Above mentioned problem is primarily due to export the audio codec of voice signal（Audio
Codec）Desired output impedance（Or say the input impedance of voice output）It is not inconsistent with actual state, thus outputs and shake
Excessive or too small voice signal.And the voice output larger in order to adapt to input impedance（Such as active loudspeaker
Deng now audio codec can face larger output impedance）To provide volume larger signal, and adapt to input impedance
Small voice output（Such as passive type loudspeaker or earphone etc., now audio codec can be in face of less output resistance
It is anti-）To provide volume less signal, current technology is the output buffer in audio codec（Output Buffer）
Connected between 110 and external voice output 120 resistance 130（As shown in Figure 1）, imitated with by the partial pressure of the resistance 130
Fruit adjusts the output to the signal energy of voice output 120, however, this kind of solution includes at least its own shortcomings：Its
One, if voice output 120 has inductively or capacitively effect, even if output buffer 110 is not with frequency adjustment output letter
Number amplitude, based on inductively or capacitively effect can with frequency change different impedance effects are presented, voice output 120
Audio still occurs the situation that low-and high-frequency volume differs, what is more, because the voice output of different size may have not
With inductively or capacitively effect, therefore designer is also difficult to comprehensively carry out accommodation；Second, audio generally on circuit board
Codec is very long to the path of audio output hole, easily by noise jamming, when resistance 130 is not provided with, and output buffer 110
Noise coupling effect is still reduced by low-down output impedance, but in the case of resistance 130 are set, output buffer
Therefore 110 anti-noise ability can detract on the contrary；Third, generally resistance 130 is the passive element with fixed resistance value on circuit board,
But the specification of voice output 120 is a lot of, the resistance 130 that designer is difficult with fixed resistance value is defeated to match all of sound
Go out device, therefore the problem attended to one thing and lose sight of another can be produced.
Other prior arts refer to the U.S. patent application case of patent publication No. 20130158921.
The content of the invention
In view of the defect of prior art, existing to solve it is an object of the invention to provide impedance detection apparatus and method
The problem of technology.
The invention discloses a kind of impedance detection device, the impedance value of a load can be detected.It is real according to of the invention one
Example is applied, the device is included：One AC signal generating circuit, for providing an AC signal；One output buffer, couples the exchange
Signal generating circuit, for being electrically connected with a load, and for producing one according to the impedance value of the AC signal and the load
Output voltage and an output current；One current mirror, couples the output buffer, for producing mirror image electricity according to the output current
Stream；One detection impedance, couples the current mirror, for producing a detection voltage according to the image current；One clock pulses produces electricity
Road, for providing a clock pulses；One comparison circuit, couples the output buffer and the detection impedance, for according to the clock
Pulse ratio is compared with the output voltage and the detection voltage producing a comparative result；And one control circuit, couple the comparison circuit
And at least one of the current mirror and the detection impedance, it is defeated with this for adjusting the image current according to the comparative result
Go out at least one of the ratio of electric current and the impedance value of the detection impedance, until comparative result satisfaction one is pre-conditioned.
In the present embodiment, the frequency of the AC signal less than a first frequency or more than a second frequency, and the AC signal with this when
There is a preset phase between clock poor.
Invention also discloses a kind of impedance detection method, the impedance value of a load can be detected.According to of the invention one
Embodiment, the method is able to carry out at least the following steps：One AC signal is provided；According to the AC signal and a resistance for loading
Anti- value produces an output voltage and an output current；An image current is produced according to the output current；Impedance is detected according to one
Impedance value and the image current produce a detection voltage；One clock pulses is provided；Compare the output voltage according to the clock pulses
With the detection voltage producing a comparative result；And the ratio of the image current and the output current is adjusted according to the comparative result
At least one of example and the impedance value of the detection impedance, until comparative result satisfaction is one pre-conditioned.In the present embodiment,
The frequency of the AC signal is present less than a first frequency or more than a second frequency, and between the AC signal and the clock pulses
One preset phase is poor.
The beneficial effects of the present invention are in sum, impedance detection apparatus and method of the invention are comprising at least following
Advantage：First, the adjustment of adaptability can be done by the impedance of the load of detection one, so as to avoid problem of the prior art；Second,
Impedance detection is carried out by AC signal, the circuit design with coupled capacitor can be applied to；Third, passing through limiting AC
The frequency and/or waveform of signal, can avoid abnormal sound；Fourth, can be accelerated by adjusting electric current and impedance impedance detection and/
Or expand the scope of impedance detection.
Feature for the present invention, practice and effect, hereby coordinate accompanying drawing to make preferred embodiment detailed description as follows.
Brief description of the drawings
Fig. 1 is the schematic diagram of the audio output framework of prior art；
Fig. 2 is the schematic diagram of an embodiment of impedance detection device of the invention；
Fig. 3 is the schematic diagram of the signal relation of Fig. 2；
Fig. 4 is the schematic diagram of an embodiment of the output buffer of Fig. 2；
Fig. 5 is the flow chart of an embodiment of impedance detection method of the invention；And
Fig. 6 is the flow chart of another embodiment of impedance detection method of the invention.
Wherein, description of reference numerals is as follows：
110 output buffers
120 voice outputs
130 resistance
200 impedance detection devices
210 AC signal generating circuits
220 output buffers
222 buffer amplifiers
224 P-type transistors
226 N-type transistors
228 coupled capacitors
230 loads
240 current mirrors
250 detection impedances
260 clock pulse generating circuits
270 comparison circuits
280 control circuits
S510 provides an AC signal
S520 produces an output voltage and an output current according to the AC signal and an impedance value for loading
S530 produces an image current according to the output current
S540 detects that the impedance value of impedance produces a detection voltage with the current value of the image current according to one
S550 provides a clock pulses
S560 compares the output voltage with the detection voltage to produce a comparative result according to the clock pulses
S570 adjusts the image current with the ratio of the output current and the impedance of the detection impedance according to the comparative result
At least one of value, until comparative result satisfaction one is pre-conditioned
S580 in the comparative result meet this it is pre-conditioned after, according to the output voltage, the image current and the output electricity
The impedance of the ratio of stream and the impedance is worth to the impedance value of the load
S590 adjusts at least one of one first yield value and one second yield value according to the impedance value of the load
Specific embodiment
The technical terms of following description is the idiom with reference to the art, and such as this specification is to part term
It is illustrated or defines, the explanation of the part term is defined by the explanation of this specification or definition.
Disclosure of the invention includes impedance detection apparatus and method, for detecting the impedance of a load.The device and
Method can be applied to an integrated circuit（Such as audio codec（Audio Codec））Or a system and device（Such as computer,
The audio output devices such as mobile phone, music player）, be embodied as it is possible under the premise of, those skilled in the art can
The present invention is realized according to the equivalent element of the disclosure of the specification selection or step, namely implementation of the invention is not limited to
The embodiment chatted afterwards.May be well known elements for the subelement that is included by impedance detection device of the invention is independent,
Therefore on the premise of the abundant open and exploitativeness for not influenceing the device to invent, the details for well known elements is below illustrated
To be omitted.Additionally, impedance detection method of the invention can by impedance detection device of the invention or its equivalent device come
Perform, on the premise of the abundant open and exploitativeness for not influenceing the method to invent, the explanation of following methods invention will focus on
In step content and non-hardware.
Fig. 2 is referred to, it is the schematic diagram of an embodiment of impedance detection device of the invention, the embodiment can be detected
The impedance value of one load is used or other utilization for output gain correction.As shown in Fig. 2 the impedance detection device of the present embodiment
200 include：One AC signal generating circuit 210, for providing an AC signal, the AC signal is, for example, a sine wave, so
And other types of AC signal（Such as average amplitude value is zero（Namely flip-flop is zero）String ripple signal, triangular wave letter
Number, square-wave signal etc.）Be embodied as it is possible under the premise of also must by the present invention be used；One output buffer（Output
Buffer）220, the AC signal generating circuit 210 is coupled, for being electrically connected with a load 230, and for believing according to the exchange
Number and the load 230 impedance value produce an output voltage and an output current；One current mirror 240, couples output buffering
Device 220, for producing an image current according to the output current, the image current is K times of the output current, and wherein K is
On the occasion of（Such as fraction or integer）, in the present embodiment, K values can adjust, and can do multiple variation with detection process, change model
Enclose, depending on the demand for implementing present inventor and the element characteristic and circuit framework for being used, if but K values must without what is adjusted
Will, or a fixed value；One detection impedance 250, couples the current mirror 240, for producing one to detect according to the image current
Voltage, in the present embodiment, the impedance value of the detection impedance 250 is adjustable；One clock pulse generating circuit 260, for carrying
For a clock pulses, the frequency of the clock pulses can be equal to the frequency or its M times or 1/N times of the AC signal, wherein M, N
It is positive integer, in the present embodiment, the clock pulse generating circuit 260 can be integrated in the AC signal generating circuit 210, right two
Person can also separate；One comparison circuit 270, couples the output buffer 220 and the detection impedance 250, for according to the clock arteries and veins
Punching compares the output voltage with the detection voltage to produce a comparative result, and the comparison circuit 270 can be single comprising one depending on demand
Bit comparator（A such as operational amplifier）Or bit comparator more than（A such as analog-digital converter（Analog-to-digital
Convertor,ADC））；And a control circuit 280, the comparison circuit 270 and the current mirror 240 are coupled with detection impedance
At least one of 250, for adjusting ratio of the image current with the output current and the detection according to the comparative result
At least one of the impedance value of impedance, until comparative result satisfaction one is pre-conditioned, in the present embodiment, the control circuit
280 can be by any combination of the combination of micro-control unit, comparator and logic circuit, lut circuits or more circuit come real
Existing, the pre-conditioned output voltage that then can be is less than a threshold value or difference continuity ground in a base with the difference of detection voltage
Upper down conversion of quasi- value etc..
Please continue to refer to Fig. 2, in the present embodiment, the AC signal generating circuit 210 is a digital analog converter（Digital-
to-Analog Convertor,DAC）, couple the control circuit 280, for starting according to the control of the control circuit 280 or
Stop producing the AC signal.Because the AC signal generating circuit 210 is realized by DAC, therefore can accurately produce institute
The AC signal for needing, certainly other known signal generator must also be used in the case of being embodied as possible by the present invention.
In addition, during impedance detection is carried out, the control circuit 280 controls the AC signal generating circuit 210 to produce exchange letter
Detection number to be continued or be interrupted；After foregoing comparative result meet this it is pre-conditioned after, the control circuit 280 controls this again
AC signal generating circuit 210 stops producing the AC signal, to make it recover a normal operation（For example carry out source audio according to one
Signal produces the running of an analogy audio signal）.Further, since foregoing output voltage and detection voltage are according to the AC signal
And produce, therefore both are periodically variable voltage, and in order to allow the comparison circuit 270 can to compare the peak value of this two voltage
To obtain relatively correct comparative result, the AC signal can be poor in the presence of a preset phase via design in advance with clock pulses,
Enable comparison circuit 270 with the triggering of the rising edge and/or trailing edge of the clock pulses to the output voltage and inspection
The peak value for surveying voltage is compared, for example, refer to Fig. 3, if the AC signal is identical with the frequency of the clock pulses,
Preset phase difference can be a quarter or 3/4ths in the cycle of the AC signal, thereby make the edge of the clock pulses
The peak value of the output voltage and the detection voltage of aliging, and cause magnitude of voltage precisely two voltage that comparison circuit 270 compared
Peak value, and then produce a relatively reliable comparative result.Furthermore, if impedance detection device 200 of the invention is applied to a sound
Frequency codec, to avoid user from hearing the abnormal sound of the AC signal, the present embodiment makes the frequency of the AC signal be less than one
First frequency or more than a second frequency, wherein first and second frequency can be the lower-frequency limit and the upper limit of human ear hearing,
Such as first frequency is 20Hz, and the second frequency is 20KHz, although different people has a different hearing limit, but described the
One with the difference of second frequency in the present embodiment at least above 10KHz.
Fig. 4 is referred to, it is the schematic diagram of an embodiment of the output buffer 220 of Fig. 2.As shown in figure 4, output buffering
Device 220 is included：One buffer amplifier 222（Buffer Amplifier）；One P-type transistor 224；One N-type transistor 226；With
And a coupled capacitor 228.The source electrode of the p-type and N-type transistor 224,226 is respectively coupled to one first bias VDD and 1 the
Two bias VEE, and the p-type is respectively intended to be carried in the positive half period and negative half-cycle of the AC signal with N-type transistor 224,226
For the output voltage.The current mirror 240 of Fig. 2 may be coupled to the two-transistor 224,226 any one to produce the image current,
When the current mirror 240 couples the P-type transistor 224 to produce the image current, foregoing preset phase difference is the AC signal
Cycle a quarter, now the comparison circuit 270 can be according to the rising edge of the clock pulses（If the phase of ac signal is led
The first clock pulses）Or trailing edge（If the phase of ac signal falls behind the clock pulses）To the output voltage and detection voltage
Crest is compared；Again when the current mirror 240 couples the N-type transistor 226 to produce the image current, the preset phase is poor
It is 3/4ths of the cycle of the AC signal, now the comparison circuit 270 can be according to the rising edge of the clock pulses（If the friendship
Stream leading clock pulses of signal phase）Or trailing edge（If the phase of ac signal falls behind the clock pulses）To the output voltage
Trough with detection voltage is compared.Note that via appropriately designed, comparison circuit 270 also can be according to the clock pulses
Rising edge is compared with trailing edge, and the art is belonged to due to how to be operated by the triggering of clock edge
Generally knowledge, therefore non-essential explanation will be omitted herein.Separately note that the design of some output buffers and do not include
The coupled capacitor of Fig. 4, carries out impedance detection using AC signal, therefore no matter whether there is the coupled capacitor yet with the present invention
, do not influence implementation of the invention.Though note that the embodiment of Fig. 2 and Fig. 4 with the output of double-width grinding/Single-end output again
As a example by buffer, however be embodied as it is possible under the premise of, those skilled in the art can regard demand and design specification
From other types of known buffer.
Fig. 2 is please referred to again, when the implementation of the comparison circuit 270 includes bit comparator more than（A such as ADC）When, this ratio
An output voltage multibit signal and a detection voltage can be produced compared with circuit 270 according to the output voltage and the detection voltage respectively
Multibit signal, and by comparing two multibit signal to produce the comparative result.Fig. 2 and Fig. 3 separately is referred to, the control circuit
280 ratios that the image current and the output current can be adjusted according to the comparative result and a preset rules（Mirror ratio）With
At least one of the impedance value of the detection impedance 250, until the comparative result meets foregoing pre-conditioned, in more detail
Say, if the control circuit 280 can only adjust the mirror ratio, the detection impedance 250 can be that a blocked impedance rather than one are adjustable
Impedance；If the control circuit 280 can only adjust the detection impedance value, the mirror ratio can be a fixed proportion（Namely the electricity
Stream mirror 240 is nonadjustable）；If the control circuit 280 can adjust the mirror ratio simultaneously or successively according to foregoing preset rules
With the detection impedance, the current mirror 240 with detection impedance 250 i.e. need as indicated above as be conditioned circuit, wherein this preset
Rule can be one according to current mirror 240 with detection impedance 250 Adjustment precision and determine rule, one adjust in turn rule,
Rule or the custom rule of this area personage that one electric current or impedance are preferentially adjusted.
From the above, comparative result meet this it is pre-conditioned after, control circuit 280 just can be according to known output voltage
（Derived from controlled AC signal）, the image current and the output current ratio and the impedance value of the detection impedance 250
Obtain it is foregoing load 230 impedance value, and can according to the impedance value of the load 230 adjust the AC signal generating circuit 210 and
At least one of gain set-point of the output buffer 220, the thereby impedance according to the load 230 is adaptively adjusted
The energy of whole output signal.For example, if impedance detection device 200 of the invention is an audio codec, the load 230
The impedance of external voice output is represented, by the present invention, no matter which kind of voice output the audio codec connects,
Control circuit 280 can estimate the impedance value of the load 230, and then accordingly adjustment exchange letter according to impedance detection result
The gain set-point of circuit 210 and/or output buffer 220 number is produced, gives the sound to export to export appropriate audio signal
Device, reaches suitable sound output effect.
In addition to said apparatus are invented, the present invention is it is also proposed that a kind of impedance detection method, can detect the impedance value of a load.
As shown in figure 5, an embodiment of the method is comprised the steps of：
Step S510：One AC signal is provided.This step can be by the AC signal generating circuit 210 of Fig. 2 or its is equivalent
Circuit is performed；
Step S520：An output voltage and an output current are produced according to the AC signal and an impedance value for loading.
This step can be performed by the output buffer 220 of Fig. 2 or its equivalent circuit；
Step S530：An image current is produced according to the output current.This step can by the current mirror 240 of Fig. 2 or its
Equivalent circuit is performed；
Step S540：Detect that the impedance value of impedance produces a detection voltage with the current value of the image current according to one.This
Step can be realized by the detection impedance 250 of Fig. 2；
Step S550：One clock pulses is provided.This step can be by the clock pulse generating circuit 260 of Fig. 2 or its is equivalent
Circuit is performed；
Step S560：Compare the output voltage with the detection voltage to produce a comparative result according to the clock pulses.This
Step can be performed by the comparison circuit 270 of Fig. 2 or its equivalent circuit；And
Step S570：Ratio of the image current with the output current and the detection impedance are adjusted according to the comparative result
At least one of impedance value, until comparative result satisfaction one is pre-conditioned.This step can be by the control circuit of Fig. 2
280 or its equivalent circuit perform.
From the above, there is a preset phase in the present embodiment, between the AC signal and the clock pulses poor, thereby make step
Rapid S560 can compare the peak value of the output voltage and the detection voltage, to produce relatively reliable comparative result, for example,
If the AC signal is identical with the frequency of the clock pulses, preset phase difference can be a quarter in the cycle of the AC signal
Or 3/4ths.In addition, for avoid the AC signal cause human ear can and abnormal sound, step S510 can limit the AC signal
Frequency is less than a first frequency（Such as 20Hz）Or more than a second frequency（Such as 20KHz）, wherein first and second frequency
Difference be more than 10KHz.Additionally, when step S560 be via bit comparator is to realize more than one when, step S560 can be wrapped further
Contain：An output voltage multibit signal is produced according to the output voltage；A detection voltage multibit signal is produced according to the detection voltage；
And compare the output voltage multibit signal with the detection voltage multibit signal to produce the comparative result.Furthermore, such as Fig. 6 institutes
Show, after abovementioned steps S510 to S570 is completed, the present embodiment can further include the following steps：
Step S580：In the comparative result meet this it is pre-conditioned after, according to the output voltage, the image current and this is defeated
The impedance of the ratio and the impedance that go out electric current is worth to the impedance value of the load；And
Step S590：According to the impedance value of the load adjust one first yield value and one second yield value at least within it
One, wherein first and second yield value is for example respectively gain set-point and the output of above-mentioned AC signal generating circuit 210
The gain set-point of buffer 220.
Finally, if the present embodiment is applied to an audio codec or similar device, step S510 can be wrapped with step S520
Contain：In the comparative result meet this it is pre-conditioned before, there is provided the AC signal and produce the output voltage；And compare knot in this
Fruit meet this it is pre-conditioned after, produce an audio signal according to an audio data and one first yield value, and according to the audio
Signal and one second yield value produce an audio signal voltage, wherein the step of producing audio signal can be by the AC signal of Fig. 2
Circuit 210 is produced to perform, now first yield value refers to the gain set-point of the AC signal generating circuit 210, and produces
The step of raw audio signal voltage, can then be performed by the output buffer 220 of Fig. 2, and now second yield value refers to the output
The gain set-point of buffer 220.
Because those skilled in the art can understand this method hair by the related disclosure of Fig. 2 to Fig. 5
Bright implementation detail and change, therefore, on the premise of the requirement of the method disclosure of the invention and exploitativeness is not influenceed, repeat and
The explanation of redundancy will be omitted.In taking off accompanying drawing before note that, order of the shape of element, size, ratio and step etc. is only
It is to understand the present invention for those skilled in the art to be used to illustrate, is not used to the limitation present invention.In addition, this technology is led
Domain personage can disclosure under this invention and the demand of itself optionally implement the part or all of technology of any embodiment
Feature, or optionally implement the combination of the part or all of technical characteristic of multiple embodiments, thereby increase the present invention and implement
When elasticity.
In sum, impedance detection apparatus and method of the invention include at least following advantages：First, can be by detection one
The adjustment of adaptability is done in the impedance of load, so as to avoid problem of the prior art；Second, carrying out impedance by AC signal
Detection, can be applied to the circuit design with coupled capacitor；Third, the frequency and/or waveform that pass through limiting AC signal, energy
Enough avoid abnormal sound；Fourth, the detection of impedance and/or the scope of expansion impedance detection can be accelerated with impedance by adjusting electric current.
Although embodiments of the invention as described above, but those embodiments be not used for limiting the present invention, this technology neck
The technical staff in domain can impose change according to the content expressed or imply of the invention to technical characteristic of the invention, all this kind
Change may belong to the patent protection category sought by the present invention, and in other words, scope of patent protection of the invention must be regarding this theory
The as defined in claim of bright book is defined.
Claims (20)
1. a kind of impedance detection device, can detect the impedance value of a load, comprising：
One AC signal generating circuit, for providing an AC signal；
One output buffer, couples the AC signal generating circuit, for being electrically connected with the load, and for believing according to the exchange
Number and the load impedance value produce an output voltage and an output current；
One current mirror, couples the output buffer, for producing an image current according to the output current；
One detection impedance, couples the current mirror, for producing a detection voltage according to the image current；
One clock pulse generating circuit, for providing a clock pulses；
One comparison circuit, couples the output buffer, the detection impedance and the clock pulse generating circuit, during for according to this
Clock compares the output voltage with the detection voltage to produce a comparative result；And
One control circuit, couples at least one of the comparison circuit and the current mirror and the detection impedance, for foundation
The comparative result adjust the ratio of the image current and the output current and the impedance value of the detection impedance at least within it
One, until comparative result satisfaction one is pre-conditioned.
2. impedance detection device as claimed in claim 1, the wherein AC signal generating circuit is a digital analog converter, coupling
The control circuit, the AC signal is produced for starting according to the control of the control circuit or stopping.
3., wherein between the AC signal and the clock pulses there is a default phase in impedance detection device as claimed in claim 1
Potential difference.
4. impedance detection device as claimed in claim 3, the wherein preset phase difference are four points of the cycle of the AC signal
One of or 3/4ths.
5. impedance detection device as claimed in claim 4, the wherein output buffer include a P-type transistor and N-type crystalline substance
Body pipe, is respectively intended to produce the output voltage in the positive half period and negative half-cycle of the AC signal, when the current mirror couples the P
To produce during the image current, preset phase difference is a quarter in the cycle of the AC signal to transistor npn npn, and works as the electricity
Stream mirror couple the N-type transistor to produce during the image current, the preset phase difference for the AC signal cycle four/
Three.
6. impedance detection device as claimed in claim 1, the wherein frequency of the AC signal are less than a first frequency or are more than
One second frequency, the difference of first and second frequency is more than 10KHz.
7. impedance detection device as claimed in claim 6, the wherein first frequency are 20Hz, and the second frequency is 20KHz.
8. impedance detection device as claimed in claim 1, the wherein AC signal is a string ripple.
9. impedance detection device as claimed in claim 1, the wherein comparison circuit be used for respectively according to the output voltage and
The detection voltage produces an output voltage multibit signal and a detection voltage multibit signal, and by comparing the output voltage multidigit
Signal and the detection voltage multibit signal are producing the comparative result.
10. impedance detection device as claimed in claim 1, wherein the control circuit are used for pre- according to the comparative result and one
If at least one of the impedance value of the ratio and the detection impedance of the rule adjustment image current and the output current, directly
Meet one to the comparative result pre-conditioned.
11. impedance detection devices as claimed in claim 1, wherein in the comparative result meet this it is pre-conditioned after, the control
Circuit is used for being worth to according to the impedance of the output voltage, the ratio of the image current and the output current and the detection impedance
The impedance value of the load, and impedance value according to the load adjusts the AC signal generating circuit and the output buffer at least
The gain set-point of one of them.
12. impedance detection devices as claimed in claim 1, it is an audio codec, and wherein the AC signal produces electricity
Road in the comparative result meet this it is pre-conditioned before export the AC signal, and in the comparative result meet this it is pre-conditioned after according to
An analogy audio signal is exported according to a source audio signal.
A kind of 13. impedance detection methods, can detect the impedance value of a load, and can perform at least the following steps：
One AC signal is provided；
An output voltage and an output current are produced according to the AC signal and the impedance value of the load；
An image current is produced according to the output current；
Detect that the impedance value of impedance produces a detection voltage with the current value of the image current according to one；
One clock pulses is provided；
Compare the output voltage with the detection voltage to produce a comparative result according to the clock pulses；And
According to the comparative result adjust the image current and the output current ratio and the detection impedance impedance value extremely
It is one of few, until comparative result satisfaction one is pre-conditioned.
Have one between 14. impedance detection methods as claimed in claim 13, the wherein AC signal and the clock pulses to preset
Phase difference.
15. impedance detection methods as claimed in claim 14, the wherein AC signal are a string ripples, and the preset phase difference is
The a quarter in the cycle of the AC signal or 3/4ths.
16. impedance detection methods as claimed in claim 13, the wherein frequency of the AC signal are less than a first frequency or big
In a second frequency, the difference of first and second frequency is more than 10KHz.
17. impedance detection methods as claimed in claim 16, the wherein first frequency are 20Hz, and the second frequency is 20KHz.
18. impedance detection methods as claimed in claim 13, wherein the step of producing the comparative result includes：
An output voltage multibit signal is produced according to the output voltage；
A detection voltage multibit signal is produced according to the detection voltage；And
Compare the output voltage multibit signal with the detection voltage multibit signal to produce the comparative result.
19. impedance detection methods as claimed in claim 13, wherein providing the AC signal and producing the output voltage
Step is included：
In the comparative result meet this it is pre-conditioned before, there is provided the AC signal and produce the output voltage；And
In the comparative result meet this it is pre-conditioned after, produce audio letter according to an audio data and one first yield value
Number, and produce an audio signal voltage according to the audio signal and one second yield value.
20. impedance detection methods as claimed in claim 19, further comprise the steps of：
In the comparative result meet this it is pre-conditioned after, according to the ratio of the output voltage, the image current and the output current
And the impedance of the impedance is worth to the impedance value of the load；And
At least one of first yield value and second yield value are adjusted according to the impedance value of the load.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310555107.8A CN104635050B (en) | 2013-11-08 | 2013-11-08 | Impedance detection apparatus and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310555107.8A CN104635050B (en) | 2013-11-08 | 2013-11-08 | Impedance detection apparatus and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104635050A CN104635050A (en) | 2015-05-20 |
| CN104635050B true CN104635050B (en) | 2017-06-09 |
Family
ID=53214019
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310555107.8A Active CN104635050B (en) | 2013-11-08 | 2013-11-08 | Impedance detection apparatus and method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104635050B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105828249B (en) * | 2015-07-01 | 2017-08-15 | 维沃移动通信有限公司 | A kind of electronic equipment and its audio frequency processing circuit, the output intent of audio signal |
| CN109089190B (en) * | 2018-10-26 | 2021-05-18 | Oppo广东移动通信有限公司 | Impedance curve determination method and device, storage medium and terminal equipment |
| CN110082279A (en) * | 2019-05-29 | 2019-08-02 | 青岛理工大学 | A method of measurement ion penetration resistance of concrete numerical value |
| CN112422104A (en) * | 2019-08-20 | 2021-02-26 | 瑞昱半导体股份有限公司 | Filter and filtering method |
| CN111308206B (en) * | 2020-02-21 | 2022-04-15 | 苏州华兴源创科技股份有限公司 | Impedance detection device and detection method thereof |
| CN113702707A (en) * | 2021-08-05 | 2021-11-26 | 芯海科技（深圳）股份有限公司 | Load impedance measuring circuit, system and electronic equipment |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1675627A (en) * | 2002-06-24 | 2005-09-28 | 阿纳洛格装置公司 | Identification system and method for recognizing any one of a number of different types of devices |
| CN1987711A (en) * | 2005-12-21 | 2007-06-27 | 松下电器产业株式会社 | Power supply circuit |
| CN101937717A (en) * | 2009-06-30 | 2011-01-05 | 台湾积体电路制造股份有限公司 | Method and circuit for measuring electrical resistance |
| CN102193031A (en) * | 2010-03-16 | 2011-09-21 | 横河电机株式会社 | AC impedance measuring device |
| CN202305673U (en) * | 2011-11-01 | 2012-07-04 | 武汉理工大学 | Alternating current (AC) impedance testing device suitable for fuel cells |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009010055A1 (en) * | 2007-07-16 | 2009-01-22 | Lab.Gruppen Ab | Method of determining an impedance function of a loudspeaker |
| US20130158921A1 (en) * | 2011-12-16 | 2013-06-20 | Qualcomm Incorporated | Load impedance detection |
-
2013
- 2013-11-08 CN CN201310555107.8A patent/CN104635050B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1675627A (en) * | 2002-06-24 | 2005-09-28 | 阿纳洛格装置公司 | Identification system and method for recognizing any one of a number of different types of devices |
| CN1987711A (en) * | 2005-12-21 | 2007-06-27 | 松下电器产业株式会社 | Power supply circuit |
| CN101937717A (en) * | 2009-06-30 | 2011-01-05 | 台湾积体电路制造股份有限公司 | Method and circuit for measuring electrical resistance |
| CN102193031A (en) * | 2010-03-16 | 2011-09-21 | 横河电机株式会社 | AC impedance measuring device |
| CN202305673U (en) * | 2011-11-01 | 2012-07-04 | 武汉理工大学 | Alternating current (AC) impedance testing device suitable for fuel cells |
Non-Patent Citations (1)
| Title |
|---|
| 带反馈检测***的高输入阻抗峰值检测电路;贺毅 等;《电测与仪表》;20010331;第38卷(第423期);第19-22、43页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104635050A (en) | 2015-05-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104635050B (en) | Impedance detection apparatus and method | |
| TWI536024B (en) | Impedance detecting device and method | |
| US10171046B2 (en) | System and method for low distortion capacitive signal source amplifier | |
| CN105163221B (en) | The method and its electric terminal of earphone active noise reduction are executed in electric terminal | |
| CN105048980B (en) | A kind of D audio frequency amplifier | |
| CN106856582A (en) | The method and system of adjust automatically tonequality | |
| CN107112965A (en) | The system and method for the audio artifacts in audio system is reduced with dynamic range enhancing | |
| US20160365083A1 (en) | Low-Power-Consumption Active Noise-Reduction In-Ear Music Headphones and Method for Noise Reduction | |
| CN101790122A (en) | Plosive eliminating circuit of audio system and mobile communication terminal | |
| TWI387359B (en) | Voltage generating apparatus for headphone | |
| CN106162484A (en) | A kind of earphone impedance detecting system, method and portable electric appts | |
| CN109428553A (en) | Bias circuit and power amplifier circuit | |
| CN102438193B (en) | Safe earphone capable of automatically muting | |
| CN203933898U (en) | A kind of VGA CARD is eliminated circuit and active noise reduction earphone | |
| CN104349249A (en) | Audio playing device and pop sound eliminating method | |
| CN105451137A (en) | User equipment wake-up method and device | |
| CN100568716C (en) | Volume controller | |
| CN102843112A (en) | Mobile communication terminal | |
| CN105228072A (en) | Acoustic calibration's system and method for work thereof | |
| CN102685636B (en) | Voice-frequency circuit | |
| CN108200519A (en) | A kind of microphone and promotion overload acoustic pressure method | |
| TWI551153B (en) | Circuit and method for driving speakers | |
| CN207783079U (en) | Intelligent earphone and intelligent audio system | |
| CN107995544B (en) | Voltage control circuit, headset type detection configuration circuit, driving circuit and method | |
| CN105677288B (en) | System and method for realizing simultaneous driving of internal and external audio output devices |
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 |