U.S. patent application number 15/351172 was filed with the patent office on 2017-03-02 for mic/gnd detection and automatic switch.
The applicant listed for this patent is Fairchild Semiconductor Corporation. Invention is credited to Seth M. Prentice.
Application Number | 20170064479 15/351172 |
Document ID | / |
Family ID | 47535391 |
Filed Date | 2017-03-02 |
United States Patent
Application |
20170064479 |
Kind Code |
A1 |
Prentice; Seth M. |
March 2, 2017 |
MIC/GND DETECTION AND AUTOMATIC SWITCH
Abstract
This document discusses, among other things, an audio jack
detection switch configured to be coupled to first and second
GND/MIC terminals of an audio jack, wherein the audio jack
detection switch includes a detection circuit configured to measure
an impedance on the first and second GND/MIC terminals and identify
each GND/MIC terminal as either a GND pole or a MIC pole using the
measured impedance, and wherein the audio jack detection switch
includes a switch configured to automatically couple an identified
MIC pole to a MIC connection and to automatically couple an
identified GND pole to a GND connection using information from the
detection circuit.
Inventors: |
Prentice; Seth M.; (Auburn,
ME) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fairchild Semiconductor Corporation |
Sunnyvale |
CA |
US |
|
|
Family ID: |
47535391 |
Appl. No.: |
15/351172 |
Filed: |
November 14, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13189480 |
Jul 22, 2011 |
9497559 |
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15351172 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04R 2420/03 20130101;
H04R 2420/01 20130101; H04R 29/004 20130101; H04R 2420/05 20130101;
H01R 2107/00 20130101; G01R 29/26 20130101; H01R 24/58 20130101;
G01R 27/02 20130101; H04R 1/02 20130101 |
International
Class: |
H04R 29/00 20060101
H04R029/00; H01R 24/58 20060101 H01R024/58 |
Claims
1. A system comprising: an audio jack detection switch configured
to be coupled to a four-pole audio jack including: a left speaker
(LSPKR) pole; a right speaker (RSPKR) pole; a ground (GND) pole;
and a microphone (MIC) pole; wherein the audio jack detection
switch includes: a detection circuit configured to measure an
impedance on at least one pole of the four-pole audio jack and to
identify the GND pole and the MIC pole using the measured
impedance; and a switch configured to automatically couple the
identified MIC pole to a MIC connection of a processor and to
automatically couple the identified GND pole to a GND connection
using information from the detection circuit.
2. An audio jack detection circuit, comprising. a first switch
configured to provide a detecting current to or to isolate a
detecting current from a first connection of an audio jack; a first
comparator configured to compare a voltage from the first
connection to a first reference voltage and to provide a first
output; and a second comparator configured to compare the voltage
from the first connection to a second reference voltage and to
provide a second output, wherein the first and second outputs
provide an indication of an impedance of the first connection of
the audio jack.
3. The audio jack detection circuit of claim 2, including: a
control circuit configured to provide a first switch signal to
control the state of the first switch, wherein the control circuit
is configured to provide the indication of the impedance of the
first connection of the audio socket using the first and second
outputs.
4. The audio jack detection circuit of claim 3, wherein the control
circuit is configured to determine an impedance range of the
impedance of the first connection of the audio socket using the
first and second outputs.
5. The audio jack detection circuit of claim 2, including a current
source configured to generate the detecting current.
6. The audio jack detection circuit of claim 2, including: a second
switch configured to automatically couple the first connection to a
MIC pole to a MIC connection of a processor and to automatically
couple the identified GND pole to a GND connection using the first
and second output from the detection circuit.
7. An audio jack detection system, comprising: a current source
configured to generate a detecting current; a first switch
configured to provide the detecting current to or to isolate the
detecting current from a first connection of an audio socket; a
control circuit configured to provide a first switch signal to
control the state of the first switch; a first comparator
configured to compare a voltage from the first connection to a
first reference voltage and to provide a first output to the
control circuit; and a second comparator configured to compare the
voltage from the first connection to a second reference voltage and
to provide a second output to the control circuit, wherein the
control circuit is configured to provide an indication of an
impedance of the first connection of the audio socket using the
first and second outputs.
8. The audio jack detection system of claim 7, wherein the control
circuit is configured to determine an impedance range of the
impedance between the first connection and a first signal pin of
the audio socket using the first and second outputs.
9. The audio jack detection system of claim 8, wherein the first
signal pin is a left speaker pin and the second signal pin is a
right signal pin.
10. The audio jack detection system of claim 7, wherein the first
signal pin is a right speaker pin and the second signal pin is a
left signal pin.
11. The audio jack detection system of claim 7, including: the
audio socket, including the first connection, the first signal pin,
a second signal pin, a ground pin, and a microphone pin; and an
audio processing unit configured to provide a first audio signal to
the first signal pin, a second audio signal to the second signal
pin, a ground signal to the ground pin, and to receive a microphone
signal from the microphone pin.
12. An audio jack detection method, comprising: selectively
providing a detecting current to a first connection of an audio
socket using a switch; comparing a voltage from the first
connection to a first reference voltage using a first comparator
and providing a first output indicative of the comparison;
comparing the voltage from the first connection to a second
reference voltage using a second comparator and providing a second
output indicative of the comparison; and providing an indication of
an impedance of the first connection of the audio socket using the
first and second outputs.
13. The audio jack detection method of claim 12, including:
determining an impedance range of the impedance between the first
connection and a first signal pin of the audio socket using the
first and second outputs.
14. The audio jack detection method of claim 12, wherein the first
signal pin is a left speaker pin and the second signal pin is a
right signal pin.
15. The audio jack detection method of claim 12, wherein the first
signal pin is a right speaker pin and the second signal pin is a
left signal pin.
Description
CLAIM OF PRIORITY
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/189,480, filed on Jul. 22, 2011, which is
incorporated by reference herein in its entirety.
BACKGROUND
[0002] Many mobile devices, such as mobile phones or other portable
electronics, include audio jacks configured to receive external
audio accessories having an audio plug. However, audio plugs can
have varying configurations, which can create issues for headset
manufacturers and end users, as manufacturers can be forced to
build specific phone configurations based on region, and end users
can be forced to use only specific accessories with their mobile
device
[0003] FIGS. 1-2 illustrate generally two example four-pole audio
jack configurations. FIG. 1 illustrates generally an example of a
four-pole audio plug 101 in an open mobile terminal platform (OMTP)
configuration including a left speaker (LSPKR) pole at pole-1, a
right speaker (RSPKR) pole at pole-2, a microphone (MIC) pole at
pole-3, and a ground (GND) pole at pole-4. FIG. 2 illustrates
generally an example of a four-pole audio jack 102 in an American
Standard configuration including a LSPKR pole at pole-1, a RSPKR
pole at pole-2, a MIC pole at pole-3, and a GND pole at pole-4. In
other examples, other configurations can be realized, for example,
a three-pole audio plug with GND poles at both pole-3 and
pole-4.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] In the drawings, which are not necessarily drawn to scale,
like numerals may describe similar components in different views.
Like numerals having different letter suffixes may represent
different instances of similar components. The drawings illustrate
generally, by way of example, but not by way of limitation, various
embodiments discussed in the present document.
[0005] FIGS. 1-2 illustrate generally example four-pole audio jack
configurations.
[0006] FIG. 3 illustrates generally an example audio jack detect on
switch.
[0007] FIG. 4 illustrates generally an example detection
circuit.
[0008] FIGS. 5-6 illustrate generally example detection flow
diagrams.
[0009] FIGS. 7-8 illustrate generally example output waveforms.
DETAILED DESCRIPTION
[0010] The present inventors have recognized, among other things,
an audio jack detection switch for three or four-pole accessories
that can detect the location of a ground (GND) pole and a
microphone (MIC) pole on an audio plug coupled to the audio jack
and automatically route the GND and MIC poles to the appropriate
connection (e.g., GND, a MIC connection of an audio sub system,
such as a codec, etc.), for example, without a separate selection
input, allowing manufacturers and end users to freely use
accessories with different pole configurations.
[0011] In an example, the audio jack detection switch can be
configured to detect and validate that an audio plug has been
coupled to an audio jack, to distinguish between three and
four-pole audio plugs, to detect the polarity of the GND and MIC
poles on a four-pole audio plug (e.g., using impedance
measurements, etc.), and to automatically route the GND and MIC
poles to the appropriate connections. In certain examples, because
mobile devices can be required to operate in noisy environments,
the audio jack detection switch can be configured to filter noise
associated with mobile communications (e.g., Global System for
Mobile Communication (GSM) noise, audio noise, etc.), such as when
detecting or measuring audio plug impedance, which can eliminate
errors in noisy environments.
[0012] FIG. 3 illustrates generally an example of a system 300
including a baseband processor 105 (e.g., of a mobile device), an
audio sub system 110 (e.g., a codec), an audio jack detection
switch 115, and an audio jack 120. In an example, the audio jack
detection switch 115 can include an oscillator and logic 116,
switch enable timing 117, a detection circuit 118, and a crosspoint
switch 119 or one or more other switches. In an example, the audio
jack 120 can include a four-pole audio jack configured to receive a
three or four-pole audio plug or other audio accessory.
[0013] In an example, the audio jack 120 can include connections
for each of the four poles, such as a left speaker (LSPKR)
connection, a right speaker (RSPKR) connection, a pole-3
connection, and a pole-4 connection.
[0014] In certain examples, the audio jack detection switch 115 can
be configured to detect and validate that an audio plug has been
received by the audio jack 120, distinguish between three and
four-pole audio plugs, and detect send/end key activation, such as
described in the commonly assigned John R. Turner et al. U.S.
patent application Ser. No. 13/188,778, entitled "Audio Jack
Detection and Configuration," filed on Jul. 22, 2011, which is
hereby incorporated by reference in its entirety. In an example,
the audio jack detection switch 115 can be configured to detect
what is connected to the pole-3 and pole-4 connections of the audio
jack. In an example, the audio jack detection switch 115 can
determine between various audio plug configurations, including at
least one of: [0015] 1) a three-pole audio plug, with the pole-3
and pole-4 plugs shorted (e.g., grounded); [0016] 2) a four-pole
audio plug, with the pole-3 plug including a MIC pole and the
pole-4 plug including a GND pole; [0017] 3) a four-pole audio plug,
with the pole-3 plug including a GND pole and the pole-4 plug
including a MIC pole; [0018] 4) floating or open connections at the
pole-3 and pole-4 plugs; or [0019] 5) one or more other
configurations, such as a video connection.
[0020] After the detection or determination is complete, the audio
jack detection switch 115 can be configured to automatically route
the poles to the appropriate connection (e.g., the MIC pole to the
MIC input of the audio sub system 110, the GND pole to a ground
connection, such as at the audio jack detection switch 115, the
audio sub system 110, the baseband processor 105, etc. In an
example, after automatically switching or routing the poles to the
appropriate connection, the audio jack detection switch 115 can be
configured to enter a low power mode to reduce power
consumption.
[0021] FIG. 4 illustrates generally an example of a system 400
including a detection circuit 118 including one or more comparators
(e.g., first and second comparators 125, 126), a resistor 127
(e.g., 40 K.OMEGA., etc.), a switch 128, and a current source 129.
In an example, the detection circuit 118 can be configured to
detect or measure the impedance of the pole-3 and pole-4
connections of the audio jack by selectively coupling one of the
GND/MIC1 or GND/MIC2 connections to the detection circuit 118. In
an example, GND/MIC1 and GND/MIC can be configured to couple the
pole-3 and pole-4 connections to the
[0022] In an example, the first and second comparators 125, 126 can
include different threshold voltages e.g., illustrated in FIG. 4 as
0.52*VDD and 0.1*VDD for the first and second comparators 125, 126,
respectively, or one or more other threshold voltages). In certain
examples, the threshold voltages can be selected or controlled to
provide different detection stages. Further, the different
threshold voltages coupled with the combination of the voltage
source VDD and the current source 129, controllable using the
switch 128, can provide multiple detection stages that can optimize
current for detecting different loads (e.g., closing the switch 128
and using the combination of VDD and the current source 129 to
detect the impedance on the GND/MIC1 or GND/MIC2 connection).
Further, the high impedance DC measurement technique can minimize
the pop & click in headphones or speakers.
[0023] In an example, the first and second comparators 125, 126 can
be used to detect GSM noise, and to distinguish between GSM noise
and audio noise. Generally, the first and second comparators 125,
126 can be monitored for state changes. If the state changes 3
clock cycles, a counter is incremented. If the state changes
continue to change for a period of time (e.g., 100 mS), the counter
can be compared to a specified range. In an example, the range can
include between 34 and 54, which corresponds to the frequency of
the GSM noise, or approximately 217 Hz. If GSM noise is determined,
the audio jack detection switch can wait and start detection again.
If the count is not within the range, it is assumed that the noise
is audio noise, and that the audio jack includes a forward bias
four-pole audio jack with pole-3 as the MIC pole.
[0024] FIG. 5 illustrates generally an example detection flow
diagram 500 including detecting the impedance of audio plug poles
(e.g., the GND and MIC poles on a four-pole audio plug, pole-3 and
pole-4, etc.) and validating the detection (e.g., using a series of
sequential detections, using different detection stages, etc.). If
the detection is invalid or unknown, the impedance can be
re-detected. In an example, if the detection is valid, the audio
jack detection switch can automatically route the poles to the
proper connections (e.g., the GND pole to a GND connection, the MIC
pole to a MIC connection on the audio sub system, etc.) and enter
an active low power state.
[0025] At 501, a baseband processor (e.g., the baseband processor
105) can provide an enable (EN) signal to an audio jack detection
switch (e.g., the audio jack detection switch 115) and, at 502, a
detection circuit (e.g., the detection circuit 118) can be turned
on. In an example, the detection circuit can be triggered by
detecting that the audio jack has received an audio plug.
[0026] At 503, a switch (e.g., the switch 128) in the detection
circuit can be opened and closed. At 504, when the detection is
complete, the state of the comparators (e.g., first and second
comparators 125, 126) can be queried.
[0027] At 504, if the state of the connections is known, at 505,
the audio jack detection switch can automatically route both the
audio plug poles to the appropriate connection (e.g., GND, MIC,
etc.), such as by using the crosspoint switch. At 506, an active
low power state can be enabled. At 507, if the enable signal
remains low for a specific time period, a disabled low power state
can be entered, and process flow can return to step 501.
[0028] At 504, if the state of the connections is unknown, a
counter can be incremented at 509. At 510, if the count is less
than a first number (e.g., 2, etc.), the process can return to step
503. At 510, if the count is equal to the first number (e.g., 2,
etc.), the audio jack detection switch can default to a three-pole
audio plug and automatically route both of the pole-3 and pole-4
connections to GND.
[0029] FIG. 6 illustrates generally an example detection flow
diagram 600 including detecting the impedance of audio plug poles.
Generally, the switch coupling the current source to the detection
circuit can be open to detect no connection or to determine if
pole-3 and pole-4 are floating. To detect for MIC polarity or for a
short, the switch can be closed.
[0030] At 601, a detection circuit can be turned on. At 602, the
switch can be opened, and the audio jack detection switch can be
configured to detect a float with a debounce of 1 mS. At 603, the
sample is taken a predetermined number of times (e.g., three times
within a sample period, (e.g., tSAMPLE*0.5, tSAMPLE*0.75,
tSAMPLE*1.0, etc.). At 604, if each of the predetermined number of
samples are detected as floating, an active low power state can be
entered at 618, and process flow can return to step 602.
[0031] Generally, when a float is detected, the detection circuit
can enter a low power mode for a specified time period (e.g.,
tPOLE). After the specified time period, the detection circuit can
detect again. If a float is detected again, the low power mode loop
can continue if the detection is not float, the detection device
can move on to test for a short or MIC polarity. If a float is ever
detected, the detection device can default back to the low power
state for the specified time period.
[0032] At 604, if each of the predetermined number of samples are
not detected as floating after a period of time at 605, the audio
jack can be detected at 606 as a four-pole audio jack and the
switch can be closed.
[0033] At 607, variables "A" and "B" are set at an initial value
and then compared, at 608, to the values of the first and second
comparators. At 610, if there are no changes to the values of the
first and second comparators, a high frequency count can be reset.
At 611, if the values of the first and second comparators are still
valid, then the detection is complete at 612. If the values of the
first and second are not valid, process flow can return to step
607.
[0034] At 608, if the values of the first and second comparators
changed, then at 609, the high frequency count can be incremented.
At 613, if the high frequency count is less than a specified number
(e.g., three, etc.), process flow can return to step 607. If the
high frequency count is equal to the specified number, the values
of variables "A" and "B" can be updated at 614 and a GSM count can
be incremented at 615. At 616, process flow returns to step 607
until a time period is reached. During this period, if the values
of the first and second comparators continues to change, the number
of GSM count, representing GSM noise, can continue to increase.
[0035] At 617, once the timer has maxed out, the GSM count can be
compared to a range, illustrated in FIG. 6 as greater than 34 but
less than 54. In an example, this range can correspond to the
approximate number of faults caused by GSM noise during the time
period of step 616, or approximately 217 Hz. If the GSM count is
not within the range, at 618 the noise at the comparator output
must be audio noise, indicating a four-pole audio jack with a
forward biased microphone and pole-3 corresponding to the MIC pole.
At 619, detection is exited. At 617, if the GSM count is within the
range, then GSM noise is causing the error, and process flow
returns to step 618.
[0036] FIG. 7 illustrates generally an example comparator output
700 including a plurality of GSM noise occurrences 705, at
approximately 217 Hz, the burst rate of the GSM transmission,
causing the output of the comparator to change values, for example,
at 710. In certain examples, the comparator changes can be counted,
and GSM noise can be distinguished from audio noise by the number
of occurrences during a specified time period.
[0037] FIG. 8 illustrates generally an example microphone audio
output 800, including a microphone output 805. When a microphone is
forward biased, the JFET type microphone can change impedance with
audio noise. During detection, these impedance changes can cause
the comparators to change states. This state change can pass the
comparator voltage references, and the audio filter will identify
when audio is present. Generally, the audio jack detection switch
can identify audio noise from GSM noise by the frequency or total
occurrences of the noise within a specified time period.
Additional Notes
[0038] The above detailed description includes references to the
accompanying drawings, which form a part of the detailed
description. The drawings show, by way of illustration, specific
embodiments in which the invention can be practiced. These
embodiments are also referred to herein as "examples." Such
examples can include elements in addition to those shown or
described. However, the present inventors also contemplate examples
in which only those elements shown or described are provided.
Moreover, the present inventors also contemplate examples using any
combination or permutation of those elements shown or described (or
one or more aspects thereof), either with respect to a particular
example (or one or more aspects thereof), or with respect to other
examples or one or more aspects thereof) shown or described
herein.
[0039] All publications, patents, and patent documents referred to
in this document are incorporated by reference herein in their
entirety, as though individually incorporated by reference. In the
event of inconsistent usages between this document and those
documents so incorporated by reference, the usage in the
incorporated reference(s) should be considered supplementary to
that of this document; for irreconcilable inconsistencies, the
usage in this document controls.
[0040] In this document, the terms "a" or "an" are used, as is
common in patent documents, to include one or more than one,
independent of any other instances or usages of "at least one" or
"one or more." In this document, the term "or" is used to refer to
a nonexclusive or such that "A or B" includes "A but not B," "B but
not A," and "A and B," unless otherwise indicated. In this
document, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Also, in the following claims, the terms "including" and
"comprising" are open-ended, that is, a system, device, article, or
process that includes elements in addition to those listed after
such a term in a claim are still deemed to fall within the scope of
that claim. Moreover, in the following claims, the terms "first,"
"second," and "third," etc. are used merely as labels, and are not
intended to impose numerical requirements on their objects.
[0041] Method examples described herein can be machine or
computer-implemented at least in part. Some examples can include a
computer-readable medium or machine-readable medium encoded with
instructions operable to configure an electronic device to perform
methods as described in the above examples. An implementation of
such methods can include code, such as microcode, assembly language
code, a higher-level language code, or the like. Such code can
include computer readable instructions for performing various
methods. The code may form portions of computer program products.
Further, in an example, the code can be tangibly stored on one or
more volatile, non-transitory, or non-volatile tangible
computer-readable media, such as during execution or at other
times. Examples of these tangible computer-readable media can
include, but are not limited to, hard disks, removable magnetic
disks, removable optical disks (e.g., compact disks and digital
video disks), magnetic cassettes, memory cards or sticks, random
access memories (RAMs), read only memories (ROMs), and the
like.
[0042] The above description is intended to be illustrative, and
not restrictive. For example, the above-described examples or one
or more aspects thereof) may be used in combination with each
other. Other embodiments can be used, such as by one of ordinary
skill in the art upon reviewing the above description. The Abstract
is provided to comply with 37 C.F.R. .sctn.1.72(b), to allow the
reader to quickly ascertain the nature of the technical disclosure.
It is submitted with the understanding that it will not be used to
interpret or limit the scope or meaning of the claims. Also, in the
above Detailed Description, various features may be grouped
together to streamline the disclosure. This should not be
interpreted as intending that an unclaimed disclosed feature is
essential to any claim. Rather, inventive subject matter may lie in
less than all features of a particular disclosed embodiment. Thus,
the following claims are hereby incorporated into the Detailed
Description, with each claim standing on its own as a separate
embodiment, and it is contemplated that such embodiments can be
combined with each other in various combinations or permutations.
The scope of the invention should be determined with reference to
the appended claims, along with the full scope of equivalents to
which such claims are entitled.
* * * * *