US20070229169A1 - Single supply direct drive amplifier - Google Patents
Single supply direct drive amplifier Download PDFInfo
- Publication number
- US20070229169A1 US20070229169A1 US11/711,480 US71148007A US2007229169A1 US 20070229169 A1 US20070229169 A1 US 20070229169A1 US 71148007 A US71148007 A US 71148007A US 2007229169 A1 US2007229169 A1 US 2007229169A1
- Authority
- US
- United States
- Prior art keywords
- amplifier
- charge pump
- voltage
- headphone
- output
- 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.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/04—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements with semiconductor devices only
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
- H03F1/02—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
- H03F1/0205—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers
- H03F1/0211—Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation in transistor amplifiers with control of the supply voltage or current
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
- H03F3/211—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
- H03F3/3069—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor the emitters of complementary power transistors being connected to the output
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/45—Differential amplifiers
- H03F3/45071—Differential amplifiers with semiconductor devices only
- H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
- H03F3/45475—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using IC blocks as the active amplifying circuit
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/504—Indexing scheme relating to amplifiers the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2200/00—Indexing scheme relating to amplifiers
- H03F2200/96—Two or more complementary transistors are coupled in a Darlington composite transistor configuration
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/007—Protection circuits for transducers
Definitions
- This invention relates generally to amplifier circuits and more particularly to single supply direct drive amplifier circuits.
- Direct drive amplifiers are used in a variety of applications. These include a host of applications where miniaturization is important, such as video and audio applications.
- the following background discussion focuses on prior art related to headphones, but the limitations described below are common to all prior art direct drive amplifiers.
- prior art direct drive amplifiers that operate from a single power supply require series output capacitors or other costly and space inefficient schemes.
- FIG. 1A illustrates a typical headphone connectivity diagram 8 .
- the right headphone lead 12 and the left headphone lead 14 couple to the right and left headphone speakers respectively represented here by a headphone load 10 to the rest of the system.
- Each headphone load 10 as well as the overall system is connected to a common ground 16 .
- FIG. 1B illustrates a prior art stereo headphones system 11 using a 3-way “jack socket” design for connecting a pair of headphones to a stereo system.
- the 3 -way jack-socket design 11 is made of three electrically isolated portions 22 , 26 , and 28 , dividers 24 and 29 , and a body 23 .
- the design of the 3 -way jack socket allows for the use of a single jack socket 11 to connect a pair of headphones via the leads 12 and 14 and the common ground lead 16 .
- FIG. 1B illustrates a prior art stereo headphones system 11 using a 3-way “jack socket” design for connecting a pair of headphones to a stereo system.
- the 3 -way jack-socket design 11 is made of three electrically isolated portions 22 , 26 , and 28 , dividers 24 and 29 , and a body 23 .
- the design of the 3 -way jack socket allows for the use of a single jack socket 11 to connect a pair of headphones via the
- the 3 -way jack-socket system 11 includes the tip 22 , which couples the left headphone speaker to the stereo system via the lead 12 .
- the middle portion 28 of the jack socket 23 couples the right headphone speaker to the stereo system via the lead 14 .
- a rear portion 26 of the jack socket 23 connects the common return for the left and the right headphones to a common ground 16 that may be connected to the stereo system chassis to form a common ground.
- Dividers 24 and 29 electrically isolate from each other, the various electrically charged portions 22 , 26 and 28 of the 3-way jack-socket.
- Each headphone may be represented by a resistive headphone load to be driven by the incoming signals.
- Typical value for the resistive load of a headphone speaker is in 16 to 32 ⁇ (ohm) range.
- FIG. 2 illustrates a typical headphone driver amplifier circuit 30 .
- the headphone driver amplifier circuit 30 includes a pair of headphone amplifiers 32 and 34 , a pair of DC coupling capacitors 40 and 42 , and a pair of outputs leads 12 and 14 connecting the headphone amplifiers to the headphone speakers represented by the headphone load 10 .
- the incoming (driving) signals are amplified before reaching each headphone.
- a single positive power supply such as a battery is the only source of power.
- headphone driver amplifiers are from a single supply (e.g. a 5 volts or 3.3 volts battery).
- the outputs of the headphone amplifiers 32 and 34 are biased at mid-rail (V DD /2) allowing for the generation of both positive and negative going signals without clipping. As a result, the output of the amplifiers 32 and 34 are at a higher DC voltage with respect to ground.
- DC coupling capacitors such as 40 and 42 are inserted in series with the output of the amplifiers 32 and 34 , in order to prevent a DC current from reaching the headphones.
- the DC coupling capacitors 40 and 42 act as a high pass filter preventing DC and very low frequency signals from reaching the headphones.
- the value of these DC coupling capacitors needs to be in the 100-470 ⁇ F (micro Farad) range.
- the physical size of a 100-470 ⁇ F capacitor is prohibitively large and prevents miniaturization of the headphone circuitry.
- the physical size and cost of these DC blocking capacitors 40 and 42 is of a greater importance in the design of portable equipment and therefore implementing an amplifier topology that either completely eliminates the DC blocking capacitors or reduces their value and size is desirable.
- the incoming signal I is input to the two power amplifiers 32 and 34 .
- the amplifiers 32 and 34 are typically biased at mid-rail (V DD /2), and thus the positive and negative power supply terminals of the two amplifiers 32 and 34 are connected to the positive power supply VDD and ground (VSS) respectively.
- V DD mid-rail
- VSS positive power supply
- the outputs 36 and 38 of the input amplifier 32 and 34 need to be coupled to the left and right headphones through DC blocking capacitors 40 and 42 respectively.
- the size of the DC blocking capacitors has to be in 100 to 470 ⁇ F range. The physical dimensions for these internal capacitors is very large and the size prevents the much desired miniaturization of the headphone driver amplifier circuit 30 .
- FIG. 3 illustrates one prior art solution eliminating the need for DC coupling capacitors.
- a prior art driver amplifier circuit 43 includes a pair of headphone amplifiers 32 and 34 directly coupled to a headphone load 10 through a pair of leads 36 and 38 , and a third amplifier 44 connected to the headphone load 10 via the lead 16 .
- the headphone load 10 (representing the headphones) is biased between ground (GND) and the supply voltage VDD. With both headphone amplifiers biased to approximately the same DC value, very little DC current flows through the headphones, and the third amplifier sinks or sources current as necessary.
- FIG. 1A illustrates a typical headphone connectivity diagram
- FIG. 1B illustrates a prior art stereo headphones design 11 using a 3-way “jack socket” design for connecting a pair of headphones to a stereo system
- FIG. 2 illustrates a typical prior art headphone driver amplifier circuit
- FIG. 3 illustrates one prior art solution eliminating the need for DC coupling capacitors
- FIG. 4 illustrates a headphone amplifier circuit according to the present invention
- FIG. 5 illustrates one embodiment of the headphone amplifier system of the present invention in a circuit
- FIG. 6 is an illustration of an alternative embodiment of a headphone amplifier system according to the present invention.
- FIG. 7 illustrates a simple capacitor based, IC charge pump circuitry
- FIG. 8 illustrates a simple capacitor based discrete charge pump circuitry
- FIG. 9 illustrates a direct drive amplifier operating from a single supply and utilizing a charge pump to generate a negative rail supply
- FIG. 10 illustrates a suitable architecture for a video amplifier in accordance with one embodiment of the present invention.
- FIG. 11 illustrates an operating diagram for a single supply direct drive video amplifier of the present invention implemented on an integrated circuit.
- One aspect of the present invention allows for driver amplifier circuits that operate from a single voltage supply, without requiring the usual series coupling capacitors necessary for preventing DC current from reaching the output.
- An on-board power supply generates a negative voltage rail, which powers the output amplifiers, allowing driver amplifier operation from both positive and negative rails. In this way, the amplifier can be biased at ground (0 volts) potential, generating no significant DC voltage across the output load (speakers, video device, etc.).
- FIG. 4 illustrates a headphone amplifier circuit 45 according to the present invention.
- the headphone amplifier circuit 45 includes a first amplifier 46 driving the left headphone, a second amplifier 48 driving the right headphone, each amplifier coupled to its respective headphone load 10 via a connecting lead 50 and 52 respectively, and a charge pump 54 .
- the headphones represented by the headphone load 10 are connected to a common ground 57 .
- a charge pump circuitry 54 is used instead of a third amplifier 44 shown in PRIOR ART FIG. 3 .
- charge pump refers to a type of DC voltage-to-voltage converter that uses capacitors, and in an alternative embodiment inductors, to store and transfer energy.
- One type of charge pump also referred to as switched-capacitor converters
- a DC voltage-to-voltage converter may be used that includes an inductor.
- the charge pump circuitry of the present invention generates a negative voltage rail ⁇ VDD with respect to ground, powering the output amplifiers and allowing driver amplifier operation from both positive and negative rails.
- Providing a negative voltage rail with respect to ground allows for the headphone amplifiers to be biased at ground voltage, allowing for the incoming signals to be amplified without clipping.
- the two headphone amplifiers 46 and 48 have their positive power terminal connected to VDD, the positive voltage supply, and VSS, which is approximately equal to the negative value of VDD with respect to ground. This arrangement allows for the output terminal of both amplifiers 46 and 48 to be biased to ground, resulting in no significant DC voltage across the headphones and allowing the elimination of the large DC coupling capacitors 40 and 42 as shown in PRIOR ART FIG. 2 .
- each of the headphone amplifiers 46 and 48 has one lead of its supply voltage terminal connected to the positive voltage rail VDD and another lead of its supply voltage terminal connected to the output 56 of the charge pump circuitry 54 supplying a negative voltage VSS equal to ⁇ VDD.
- the headphone amplifier circuit 45 allows for the headphone 10 to be biased at zero volts, operating between VDD and ⁇ VDD which in turn allows for the leads 50 and 52 of the respective headphone amplifiers 46 and 48 to directly couple the headphone speakers 10 to the headphone amplifiers 46 and 48 without the need for any DC coupling capacitors in series.
- FIG. 5 illustrates one embodiment of the headphone amplifier system of the present invention in a circuit.
- the headphone amplifier system 145 includes a left headphone amplifier 46 , a right headphone amplifier 48 , a charge pump 54 , and external capacitors C 1 and C 2 .
- the charge pump circuitry 54 and the power amplifiers 46 and 48 are implemented on a single integrated circuit (IC) chip 145 .
- the charge pump 54 operation requires two small external capacitors C 1 and C 2 .
- C 1 is a called a “flying capacitor”
- C 2 is a “reservoir capacitor”.
- the size of these two external capacitors are in the single digit micro Farad ( ⁇ F) range as compared to the DC coupling capacitors of the prior art which are in the several hundred ⁇ F range.
- FIG. 6 is an illustration of an alternative embodiment of a headphone amplifier system according to the present invention.
- the headphone driver circuit 58 includes a first amplifier 60 , a second amplifier 62 , a switching unit 64 , an external inductor L 1 and an external capacitor C 2 .
- the inventive teachings of the present invention may further be implemented using an inductor based DC voltage-to-voltage converter.
- the headphone driver circuit 58 may be implemented using discrete circuit components.
- an onboard inductor L 1 may be used in conjunction with an integrated circuit that includes an integrated switching system as well as power amplifiers for driving the headphones.
- an external inductor L 1 is used in conjunction with an external capacitor C 1 , to convert a positive power supply voltage to a substantially equal but negative voltage supply.
- a switching unit 64 configures the circuit for each charge and discharge cycle.
- the headphone amplifiers 60 and 62 may be directly coupled to and drive their respective headphones without the need for DC coupling capacitors since the headphones are biased to ground and operate between VDD and ⁇ VDD, allowing for a complete incoming signal representation without any clipping.
- FIG. 7 is illustrates a simple capacitor-based, IC charge pump circuitry 66 .
- the simple capacitor based IC charge pump circuitry 66 includes a pair of amplifier/inverters 68 and 70 , an oscillator 72 , a pair of switches 74 and 76 , and a pair of external capacitors C 1 and C 2 .
- the switch network 74 and 76 toggles between charge and discharge states.
- An oscillator (OSC) 72 controls the two switches ( 74 and 76 ) that alternately charge a flying capacitor (C 1 ) from an input voltage supplied by the amplifier 68 and 70 , and discharge the flying capacitor (C 1 ) into an output capacitor (C 2 ). The voltage thus produced across the output capacitor C 2 may be output as the output voltage (VOUT).
- the oscillator 72 , the switches 74 and 76 , and still other controls are all commonly contained in a single integrated circuit (IC).
- the simple capacitor based IC charge pump circuitry 66 is of the inverting type, and it operates by lowering the potential of the charge in the flying capacitor C 1 below ground, and then discharging the output capacitor C 2 with this.
- the optimal result of this is an output voltage VOUT that is the negative of the input voltage.
- inverting charge pump operates in this way, but further includes an appreciable resistance in the charge path to the flying capacitor.
- the resistance intentionally introduces a delay in the charging of the flying capacitor, and appropriate control of the oscillator is then used to switch the charge before it is able to reach the full input voltage potential.
- This type of charge pump may accordingly transfer charge quanta having only one-half, two-thirds, etc. of the input voltage, and thereby produce an output voltage which is correspondingly lower than the input voltage.
- This type of step-down charge pump is probably primarily the most common today, but it is not the only type possible.
- Alternative circuit arrangements allow for the generation of an output voltage VOUT that is equal to some negative quanta of the input voltage.
- FIG. 8 illustrates a simple capacitor based discrete charge pump circuitry.
- the simple capacitor based discrete charge pump circuitry 78 includes an amplifier 80 , a pair of capacitors C 1 and C 2 , a pair of diodes or switches D 1 and D 2 and includes an input signal or external clock.
- the basic charge pump circuit is implemented in a discrete component circuit as shown in FIG. 8 .
- the output of the amplifier 80 is approximately V+
- the amplifier 80 charges the flying capacitor C 1 through the diode D 1 .
- the capacitor C 1 discharges the capacitor C 2 through the diode D 2 .
- a reservoir capacitor C 2 holds the charge and filters the output voltage VOUT.
- the external clock signal along with the two diodes D 1 and D 2 control the cycle and direction of the charge and discharge signals.
- FIG. 9 illustrates a single supply direct drive circuit 100 having a single output in accordance with one embodiment of the present invention.
- the circuit 100 includes an amplifier 102 and a DC-to-DC voltage converter 104 .
- the amplifier 102 may be well suited for driving a video load, as described below with reference to FIG. 10 .
- the voltage converter 104 may be any suitable device such as a capacitive based charge pump, an inductor based converter, etc. Such devices are described above in more detail.
- the embodiment of FIG. 9 can be used in a context where only a single output signal is necessary. In particular, a video amplifier is contemplated.
- FIG. 10 illustrates one suitable embodiment for the amplifier 102 of FIG. 9 .
- the amplifier 102 includes a transconductance stage 120 , first and second parallel coupled transistors 122 and 124 , a current device 126 sourcing current to the first parallel coupled transistor 122 , a current device 128 sinking current from the second parallel coupled transistor 124 , and first and second output transistors 130 and 132 .
- the transconductance stage includes a degenerated differential pair of transistors.
- FIG. 11 illustrates an operating diagram of a single supply direct drive video circuit in accordance with one embodiment of the present invention as an integrated circuit package 150 .
- the IC 150 includes a shutdown circuit, a buffer amplifier 154 , a low pass or reconstruction filter 156 , a DC level shift capacitor 158 , a video amplifier 160 , a charge pump 162 , and a linear regulator 164 .
- the low pass filter 156 should provide the desired filter response for the application, and may be a 3-pole or 4-pole filter.
- the video amplifier 160 and the charge pump 162 can take any suitable form such as those described earlier.
- the charge pump 16 or other negative voltage supply generator may create a “noisy” negative voltage supply. Accordingly, the linear regulator 164 is an optional component that can be included to provide the video amplifier with a quiet negative voltage supply.
- the IC 150 provides a single supply video amplifier without the need for the bulky, expensive external capacitors of the prior art.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
- Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
Abstract
A driver amplifier operative from a single DC voltage supply, coupled directly to the output load without the need for DC coupling capacitors used for preventing DC reaching the output load. An onboard power supply generates a negative voltage rail that powers the output amplifiers, allowing driver amplifier operation from both positive and negative rails. Since the amplifiers can be biased at ground potential (0 volts), no significant DC voltage exists across the load and the need for DC coupling capacitors is eliminated.
Description
- The present application is a continuation of U.S. patent application Ser. No. 11/039,386, filed Jan. 18, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 10/056,994, filed Jan. 24, 2002, entitled SINGLE SUPPLY HEADPHONE DRIVER/CHARGE PUMP COMBINATION, both of which are incorporated herein by reference. The present application also claims priority to U.S. Provisional Patent Application No. 60/592,868, filed Jul. 29, 2004, entitled SINGLE SUPPLY DIRECT DRIVE AMPLIFIER, which is incorporated herein by reference.
- This invention relates generally to amplifier circuits and more particularly to single supply direct drive amplifier circuits.
- Direct drive amplifiers are used in a variety of applications. These include a host of applications where miniaturization is important, such as video and audio applications. The following background discussion focuses on prior art related to headphones, but the limitations described below are common to all prior art direct drive amplifiers. In particular, prior art direct drive amplifiers that operate from a single power supply require series output capacitors or other costly and space inefficient schemes.
- PRIOR ART
FIG. 1A illustrates a typical headphone connectivity diagram 8. The right headphone lead 12 and the left headphone lead 14 couple to the right and left headphone speakers respectively represented here by aheadphone load 10 to the rest of the system. Each headphone load 10 as well as the overall system is connected to acommon ground 16. - PRIOR ART
FIG. 1B illustrates a prior artstereo headphones system 11 using a 3-way “jack socket” design for connecting a pair of headphones to a stereo system. As shown inFIG. 1B , the 3-way jack-socket design 11 is made of three electrically isolatedportions dividers body 23. The design of the 3-way jack socket allows for the use of asingle jack socket 11 to connect a pair of headphones via theleads common ground lead 16. As illustrated herein PRIOR ARTFIG. 1A , the 3-way jack-socket system 11 includes thetip 22, which couples the left headphone speaker to the stereo system via thelead 12. Similarly, themiddle portion 28 of thejack socket 23 couples the right headphone speaker to the stereo system via thelead 14. Arear portion 26 of thejack socket 23 connects the common return for the left and the right headphones to acommon ground 16 that may be connected to the stereo system chassis to form a common ground.Dividers portions - Each headphone may be represented by a resistive headphone load to be driven by the incoming signals. Typical value for the resistive load of a headphone speaker is in 16 to 32 Ω (ohm) range.
- PRIOR ART
FIG. 2 illustrates a typical headphonedriver amplifier circuit 30. The headphonedriver amplifier circuit 30 includes a pair ofheadphone amplifiers DC coupling capacitors headphone load 10. - As shown in PRIOR ART
FIG. 2 , the incoming (driving) signals are amplified before reaching each headphone. In the cases where the headphones are used with portable electronic devices such as portable cassette players or portable CD players, a single positive power supply such as a battery is the only source of power. In a typical portable device, headphone driver amplifiers are from a single supply (e.g. a 5 volts or 3.3 volts battery). In order to accurately reflect the incoming signals amplified by theheadphone amplifiers headphone amplifiers amplifiers - In order to prevent high currents from flowing through the headphones and having the headphones in a continuously on state, direct current (DC) coupling capacitors such as 40 and 42 are inserted in series with the output of the
amplifiers DC coupling capacitors DC blocking capacitors - Returning to PRIOR ART
FIG. 2 , the incoming signal I is input to the twopower amplifiers amplifiers amplifiers outputs input amplifier DC blocking capacitors driver amplifier circuit 30. - PRIOR ART
FIG. 3 illustrates one prior art solution eliminating the need for DC coupling capacitors. A prior artdriver amplifier circuit 43 includes a pair ofheadphone amplifiers headphone load 10 through a pair ofleads third amplifier 44 connected to theheadphone load 10 via thelead 16. The headphone load 10 (representing the headphones) is biased between ground (GND) and the supply voltage VDD. With both headphone amplifiers biased to approximately the same DC value, very little DC current flows through the headphones, and the third amplifier sinks or sources current as necessary. Although the circuit depicted in PRIOR ARTFIG. 3 eliminates the need for large DC coupling capacitors, this system has the disadvantage of having acommon return 16 that must now be isolated from the equipment chassis since it has a DC voltage on it. This isolation introduces additional problems such as possible circuit damage if the electrical isolation of the common return from the rest of the system fails. - Therefore, it is desirable to provide a direct drive amplifier system that operates from a single voltage supply, and which does not require the usual large DC coupling capacitors or need the physical isolation of the common return of the amplifier.
- PRIOR ART
FIG. 1A illustrates a typical headphone connectivity diagram; - PRIOR ART
FIG. 1B illustrates a prior artstereo headphones design 11 using a 3-way “jack socket” design for connecting a pair of headphones to a stereo system; - PRIOR ART
FIG. 2 illustrates a typical prior art headphone driver amplifier circuit; - PRIOR ART
FIG. 3 illustrates one prior art solution eliminating the need for DC coupling capacitors; -
FIG. 4 illustrates a headphone amplifier circuit according to the present invention; -
FIG. 5 illustrates one embodiment of the headphone amplifier system of the present invention in a circuit; -
FIG. 6 is an illustration of an alternative embodiment of a headphone amplifier system according to the present invention; -
FIG. 7 illustrates a simple capacitor based, IC charge pump circuitry; -
FIG. 8 illustrates a simple capacitor based discrete charge pump circuitry; -
FIG. 9 illustrates a direct drive amplifier operating from a single supply and utilizing a charge pump to generate a negative rail supply; -
FIG. 10 illustrates a suitable architecture for a video amplifier in accordance with one embodiment of the present invention; and -
FIG. 11 illustrates an operating diagram for a single supply direct drive video amplifier of the present invention implemented on an integrated circuit. - Prior art amplifier driver systems for video and audio devices that operate from a single power supply require biasing the output at mid-range of the power supply in order to fully represent the incoming signal without the danger of any clipping. As a result, these prior art systems require that DC blocking capacitors be used in series with the amplifiers driving the output. The value and physical size of these DC coupling capacitors are prohibitively large and limit miniaturization, which is highly desired in most systems.
- One aspect of the present invention allows for driver amplifier circuits that operate from a single voltage supply, without requiring the usual series coupling capacitors necessary for preventing DC current from reaching the output. An on-board power supply generates a negative voltage rail, which powers the output amplifiers, allowing driver amplifier operation from both positive and negative rails. In this way, the amplifier can be biased at ground (0 volts) potential, generating no significant DC voltage across the output load (speakers, video device, etc.).
-
FIG. 4 illustrates aheadphone amplifier circuit 45 according to the present invention. Theheadphone amplifier circuit 45 includes afirst amplifier 46 driving the left headphone, asecond amplifier 48 driving the right headphone, each amplifier coupled to itsrespective headphone load 10 via a connectinglead 50 and 52 respectively, and acharge pump 54. The headphones represented by theheadphone load 10 are connected to acommon ground 57. As shown inFIG. 4 , instead of athird amplifier 44 shown in PRIOR ARTFIG. 3 a charge pump circuitry 54 is used. - The term “charge pump” refers to a type of DC voltage-to-voltage converter that uses capacitors, and in an alternative embodiment inductors, to store and transfer energy. One type of charge pump (also referred to as switched-capacitor converters) includes a switch/diode network that charges and discharges one or more capacitors. Alternatively, in implementing the present invention, a DC voltage-to-voltage converter may be used that includes an inductor.
- The charge pump circuitry of the present invention generates a negative voltage rail −VDD with respect to ground, powering the output amplifiers and allowing driver amplifier operation from both positive and negative rails. Providing a negative voltage rail with respect to ground allows for the headphone amplifiers to be biased at ground voltage, allowing for the incoming signals to be amplified without clipping. As shown in
FIG. 4 , the twoheadphone amplifiers amplifiers DC coupling capacitors FIG. 2 . - Returning to
FIG. 4 , each of theheadphone amplifiers output 56 of thecharge pump circuitry 54 supplying a negative voltage VSS equal to −VDD. - The
headphone amplifier circuit 45 allows for theheadphone 10 to be biased at zero volts, operating between VDD and −VDD which in turn allows for theleads 50 and 52 of therespective headphone amplifiers headphone speakers 10 to theheadphone amplifiers -
FIG. 5 illustrates one embodiment of the headphone amplifier system of the present invention in a circuit. The headphone amplifier system 145 includes aleft headphone amplifier 46, aright headphone amplifier 48, acharge pump 54, and external capacitors C1 and C2. As shown inFIG. 5 , in one embodiment of the present invention, thecharge pump circuitry 54 and thepower amplifiers charge pump 54 operation requires two small external capacitors C1 and C2. C1 is a called a “flying capacitor” and C2 is a “reservoir capacitor”. The size of these two external capacitors are in the single digit micro Farad (μF) range as compared to the DC coupling capacitors of the prior art which are in the several hundred μF range. -
FIG. 6 is an illustration of an alternative embodiment of a headphone amplifier system according to the present invention. As shown inFIG. 6 , theheadphone driver circuit 58 includes afirst amplifier 60, asecond amplifier 62, a switchingunit 64, an external inductor L1 and an external capacitor C2. The inventive teachings of the present invention may further be implemented using an inductor based DC voltage-to-voltage converter. In one embodiment, theheadphone driver circuit 58 may be implemented using discrete circuit components. In an alternative embodiment, an onboard inductor L1 may be used in conjunction with an integrated circuit that includes an integrated switching system as well as power amplifiers for driving the headphones. In this embodiment, an external inductor L1 is used in conjunction with an external capacitor C1, to convert a positive power supply voltage to a substantially equal but negative voltage supply. A switchingunit 64 configures the circuit for each charge and discharge cycle. Theheadphone amplifiers -
FIG. 7 is illustrates a simple capacitor-based, ICcharge pump circuitry 66. The simple capacitor based ICcharge pump circuitry 66 includes a pair of amplifier/inverters oscillator 72, a pair ofswitches - In the simple capacitor based IC
charge pump circuitry 66, theswitch network amplifier oscillator 72, theswitches - The simple capacitor based IC
charge pump circuitry 66 is of the inverting type, and it operates by lowering the potential of the charge in the flying capacitor C1 below ground, and then discharging the output capacitor C2 with this. The optimal result of this is an output voltage VOUT that is the negative of the input voltage. - One very common type of inverting charge pump operates in this way, but further includes an appreciable resistance in the charge path to the flying capacitor. The resistance intentionally introduces a delay in the charging of the flying capacitor, and appropriate control of the oscillator is then used to switch the charge before it is able to reach the full input voltage potential. This type of charge pump may accordingly transfer charge quanta having only one-half, two-thirds, etc. of the input voltage, and thereby produce an output voltage which is correspondingly lower than the input voltage. This type of step-down charge pump is probably overwhelmingly the most common today, but it is not the only type possible. Alternative circuit arrangements allow for the generation of an output voltage VOUT that is equal to some negative quanta of the input voltage.
-
FIG. 8 illustrates a simple capacitor based discrete charge pump circuitry. The simple capacitor based discretecharge pump circuitry 78 includes anamplifier 80, a pair of capacitors C1 and C2, a pair of diodes or switches D1 and D2 and includes an input signal or external clock. In the capacitor based discretecharge pump circuit 78, the basic charge pump circuit is implemented in a discrete component circuit as shown inFIG. 8 . When the output of theamplifier 80 is approximately V+, theamplifier 80 charges the flying capacitor C1 through the diode D1. When the output ofamplifier 80 is approximately ground, the capacitor C1 discharges the capacitor C2 through the diode D2. A reservoir capacitor C2 holds the charge and filters the output voltage VOUT. The external clock signal along with the two diodes D1 and D2 control the cycle and direction of the charge and discharge signals. -
FIG. 9 illustrates a single supplydirect drive circuit 100 having a single output in accordance with one embodiment of the present invention. Thecircuit 100 includes anamplifier 102 and a DC-to-DC voltage converter 104. Theamplifier 102 may be well suited for driving a video load, as described below with reference toFIG. 10 . Thevoltage converter 104 may be any suitable device such as a capacitive based charge pump, an inductor based converter, etc. Such devices are described above in more detail. In contrast with the headphone examples ofFIGS. 1-8 , the embodiment ofFIG. 9 can be used in a context where only a single output signal is necessary. In particular, a video amplifier is contemplated. -
FIG. 10 illustrates one suitable embodiment for theamplifier 102 ofFIG. 9 . As will be appreciated, the architecture ofFIG. 10 is straight-forward and well suited for driving a video load. Theamplifier 102 includes atransconductance stage 120, first and second parallel coupledtransistors current device 126 sourcing current to the first parallel coupledtransistor 122, acurrent device 128 sinking current from the second parallel coupledtransistor 124, and first andsecond output transistors -
FIG. 11 illustrates an operating diagram of a single supply direct drive video circuit in accordance with one embodiment of the present invention as anintegrated circuit package 150. Although certain connections are not shown, those skilled in the art will readily understand operation of the video circuit from the diagram. TheIC 150 includes a shutdown circuit, abuffer amplifier 154, a low pass orreconstruction filter 156, a DClevel shift capacitor 158, avideo amplifier 160, acharge pump 162, and alinear regulator 164. Thelow pass filter 156 should provide the desired filter response for the application, and may be a 3-pole or 4-pole filter. Thevideo amplifier 160 and thecharge pump 162 can take any suitable form such as those described earlier. Thecharge pump 16 or other negative voltage supply generator may create a “noisy” negative voltage supply. Accordingly, thelinear regulator 164 is an optional component that can be included to provide the video amplifier with a quiet negative voltage supply. TheIC 150 provides a single supply video amplifier without the need for the bulky, expensive external capacitors of the prior art. - The foregoing examples illustrate certain exemplary embodiments of the invention from which other embodiments, variations, and modifications will be apparent to those skilled in the art. As will be further appreciated, the circuit of the present invention is well suited for use in portable applications such as cellular telephones, digital cameras, portable computers, etc. The invention should therefore not be limited to the particular embodiments discussed above, but rather is defined by the following claims.
Claims (18)
1. A circuit enabling a driver amplifier to operate from a single voltage supply comprising:
an amplifier having an output arranged for coupling to an output load, said amplifier having first and second power supply leads, said first power supply lead connected to a power supply voltage, wherein the output of the amplifier is coupled to the output load without an intervening DC coupling capacitor;
a charge pump DC voltage-to-voltage converter having an output, said DC voltage-to-voltage converter having a power source lead connected to the supply voltage, the output of said DC voltage-to-voltage converter connected to the second power supply lead, and said DC voltage-to-voltage converter generating an output voltage at the output that is substantially equal in magnitude to some negative quanta of the power supply voltage; and a shutdown circuit operable to control operation of said circuit.
2. The circuit of claim 1 connected to a common ground by two external capacitors in the range of 0.47 to 3.3 micro farads.
3. An amplifier circuitry for directly driving stereo headphones, said amplifier circuitry being driven by a single supply voltage VDD, said amplifier circuitry comprising:
a first and a second amplifier, the first amplifier having an output coupled to a first headphone without any intervening DC coupling capacitor and the second amplifier having an output coupled to a second headphone without any intervening DC coupling capacitor, each of the first and second amplifier having a VDD power supply lead connected to a positive voltage supply VDD; and
a charge pump circuitry output connected to a −VDD supply voltage of the first and second amplifier, wherein said charge pump circuitry output provides a voltage substantially equal in magnitude to a negative quanta of the VDD supply, said charge pump further having a power supply lead connected to the VDD supply voltage.
4. A circuit enabling a driver amplifier to operate from a single voltage supply comprising:
an amplifier having an output arranged for coupling to an output load, said amplifier having first and second power supply leads, said first power supply lead connected to a power supply voltage, wherein the output of the amplifier is coupled to the output load without an intervening DC coupling capacitor;
a charge pump having an output, said charge pump having a power source lead connected to the supply voltage, and said charge pump generating an output voltage at the output that is substantially equal in magnitude to some negative quanta of the power supply voltage; and
a linear regulator having an input and an output, the output of the charge pump connected to the input of the linear regulator, and the output of the linear regulator coupled to the second power supply lead of the amplifier.
5. A driver amplifier circuit comprising:
an amplifier having an output coupled to a load without an intervening DC coupling capacitor, the amplifier having a positive power lead and a negative power lead,
a voltage supply coupled to the positive power lead, the voltage supply providing a positive voltage, and
a charge pump coupled to the voltage supply, the charge pump having an output coupled to the negative power lead of the amplifier, the output of the charge pump being a negative voltage;
wherein the negative voltage is substantially equal in magnitude to a quanta of the positive voltage.
6. A direct drive charge pump enabled stereo headphone system comprising the following formed on a single integrated circuit:
a single power input for providing, internal to said integrated circuit;
a VDD supply voltage originating external to said integrated circuit;
a charge pump coupled to said single power input and operable to provide, internal to said integrated circuit,
a voltage substantially equal in magnitude to a negative quanta of said external VDD supply;
a first headphone amplifier power by both said external VDD supply and said voltage substantially equal in magnitude to the negative quanta of said external VDD supply, said first headphone amplifier having a first audio input driven by a first audio signal provided external to said integrated circuit, and a first audio output suitable for driving a stereo headphone without any intervening DC coupling capacitor;
a second headphone amplifier powered by both said external VDD supply and said voltage substantially equal in magnitude to the negative quanta of said external VDD supply, said second headphone amplifier having a second audio input driven by a second audio signal provided external to said integrated circuit; and a second audio output suitable for driving said stereo headphone without any intervening DC coupling capacitor.
7. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , wherein said first audio input is an audio in for a right stereo headphone and said second audio input is an audio in for a left stereo headphone.
8. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , wherein said first audio input is coupled to an inverting terminal of said first headphone amplifier and said second audio input is coupled to an inverting terminal of said second headphone amplifier.
9. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , wherein a non-inverting terminal of said first headphone amplifier is coupled to a non-inverting terminal of said second headphone amplifier.
10. A direct drive charge pump enabled stereo headphone system as recited in claim 9 , wherein said non-inverting terminal of said first headphone amplifier and said non-inverting terminal of said second headphone amplifier are coupled to ground.
11. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising:
a first resistor coupled to said first audio input and an inverting terminal of said first headphone amplifier,
a second resistor coupled to said first audio output and said inverting terminal of said first headphone amplifier,
a third resistor coupled to said second audio input and an inverting terminal of said second headphone amplifier, and
a fourth resistor coupled to said second audio output and said inverting terminal of said second headphone amplifier.
12. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising:
a first capacitor having a first lead and a second lead, said first lead coupled to said charge pump and said second lead coupled to said charge pump, said first capacitor located off said integrated chip, and
a second capacitor having a first lead and a second lead, said first lead coupled to said charge pump and said second lead couple to ground, said second capacitor located off said integrated chip.
13. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising a short circuit protection device.
14. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising a bias circuitry device.
15. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising a click/pop suppression device coupled to said first headphone amplifier and said second headphone amplifier.
16. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising a shutdown control device coupled to said charge pump.
17. A direct drive charge pump enabled stereo headphone system as recited in claim 15 , further comprising a shutdown control device coupled to said charge pump and said click/pop suppression device.
18. A direct drive charge pump enabled stereo headphone system as recited in claim 6 , further comprising:
a first capacitor having a first lead and a second lead, said first lead coupled to a non-inverting terminal of said first headphone amplifier and said second lead coupled to said first audio input, said first capacitor located off said integrated chip, and
a second capacitor having a first lead and a second lead, said first lead coupled to a non-inverting terminal of said second headphone amplifier and said second lead coupled to said second audio input, said second capacitor located off said integrated chip.
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/711,480 US20070229169A1 (en) | 2002-01-24 | 2007-02-26 | Single supply direct drive amplifier |
US12/116,144 US7714661B2 (en) | 2002-01-24 | 2008-05-06 | Single supply direct drive amplifier |
US12/661,251 US8638170B2 (en) | 2002-01-24 | 2010-03-12 | Single supply headphone driver/charge pump combination |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/056,994 US7061327B2 (en) | 2002-01-24 | 2002-01-24 | Single supply headphone driver/charge pump combination |
US59286804P | 2004-07-29 | 2004-07-29 | |
US11/039,386 US7183857B2 (en) | 2002-01-24 | 2005-01-18 | Single supply direct drive amplifier |
US11/711,480 US20070229169A1 (en) | 2002-01-24 | 2007-02-26 | Single supply direct drive amplifier |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/039,386 Continuation US7183857B2 (en) | 2002-01-24 | 2005-01-18 | Single supply direct drive amplifier |
Related Child Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/116,144 Continuation US7714661B2 (en) | 2002-01-24 | 2008-05-06 | Single supply direct drive amplifier |
US12/206,631 Continuation US8476978B2 (en) | 2002-01-24 | 2008-09-08 | Headphone driver/charge pump combination |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070229169A1 true US20070229169A1 (en) | 2007-10-04 |
Family
ID=36060470
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/039,386 Expired - Lifetime US7183857B2 (en) | 2002-01-24 | 2005-01-18 | Single supply direct drive amplifier |
US11/711,480 Abandoned US20070229169A1 (en) | 2002-01-24 | 2007-02-26 | Single supply direct drive amplifier |
US12/116,144 Expired - Lifetime US7714661B2 (en) | 2002-01-24 | 2008-05-06 | Single supply direct drive amplifier |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/039,386 Expired - Lifetime US7183857B2 (en) | 2002-01-24 | 2005-01-18 | Single supply direct drive amplifier |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/116,144 Expired - Lifetime US7714661B2 (en) | 2002-01-24 | 2008-05-06 | Single supply direct drive amplifier |
Country Status (7)
Country | Link |
---|---|
US (3) | US7183857B2 (en) |
EP (3) | EP1771943B1 (en) |
JP (1) | JP2007531419A (en) |
AT (1) | ATE466401T1 (en) |
DE (1) | DE602005020937D1 (en) |
TW (1) | TWI311399B (en) |
WO (1) | WO2006031304A2 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060183509A1 (en) * | 2005-02-16 | 2006-08-17 | Shuyong Shao | DC power source for an accessory of a portable communication device |
US20070202854A1 (en) * | 2006-01-13 | 2007-08-30 | Samsung Electronics Co., Ltd. | Terminal apparatus and method for providing media transmission time information in a PoC system and PoC system for the same |
US20080144857A1 (en) * | 2006-12-19 | 2008-06-19 | Shih-Hang Huang | Audio signal output circuit capable of decreasing pop noise |
US20080159567A1 (en) * | 2006-12-22 | 2008-07-03 | Lesso John P | Audio amplifier circuit and electronic apparatus including the same |
US20090302950A1 (en) * | 2007-01-10 | 2009-12-10 | Alexandre Pujol | Single input dual output voltage power supply and method therefor |
EP2262106A1 (en) | 2009-06-12 | 2010-12-15 | ST-Ericsson SA | Circuit for an amplifier |
US20110206942A1 (en) * | 2008-09-16 | 2011-08-25 | Patrick Schiebel | Connections Between a Monolithic Metal Component and a Continuous-Fiber Reinforced Laminate Component, and Method for Production of the Same |
US8471628B2 (en) | 2008-10-21 | 2013-06-25 | Semiconductor Components Industries, Llc | Amplifier with reduced output transients and method therefor |
US20140086432A1 (en) * | 2011-12-16 | 2014-03-27 | Ipgoal Microelectronics (Sichuan) Co., Ltd. | POP noise suppression circuit and system |
Families Citing this family (40)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7061327B2 (en) * | 2002-01-24 | 2006-06-13 | Maxim Integrated Products, Inc. | Single supply headphone driver/charge pump combination |
US7183857B2 (en) * | 2002-01-24 | 2007-02-27 | Maxim Integrated Products Inc. | Single supply direct drive amplifier |
US7714851B2 (en) * | 2004-09-08 | 2010-05-11 | Intersil Americas Inc. | Single supply video line driver |
US8213141B2 (en) * | 2006-01-17 | 2012-07-03 | Broadcom Corporation | Power over Ethernet electrostatic discharge protection circuit |
GB2446843B (en) | 2006-06-30 | 2011-09-07 | Wolfson Microelectronics Plc | Amplifier circuit and methods of operation thereof |
US7925030B2 (en) * | 2006-07-08 | 2011-04-12 | Telefonaktiebolaget Lm Ericsson (Publ) | Crosstalk cancellation using load impedence measurements |
US8311243B2 (en) * | 2006-08-21 | 2012-11-13 | Cirrus Logic, Inc. | Energy-efficient consumer device audio power output stage |
US8068622B2 (en) * | 2006-12-13 | 2011-11-29 | Cirrus Logic, Inc. | Method and apparatus for controlling a selectable voltage audio power output stage |
KR100770747B1 (en) | 2006-08-23 | 2007-10-29 | 삼성전자주식회사 | Digital amplifier and method of reproducing sound |
GB2441218B (en) * | 2006-08-23 | 2011-08-10 | Samsung Electronics Co Ltd | Method,apparatus and system for reducing dc coupling capacitance at switching amplifier |
KR100839487B1 (en) | 2006-10-16 | 2008-06-19 | 삼성전자주식회사 | Pop-up noise prevention circuit, digital amplifier including the same and method of preventing pop-up noise in an digital amplifier |
GB2444984B (en) * | 2006-12-22 | 2011-07-13 | Wolfson Microelectronics Plc | Charge pump circuit and methods of operation thereof |
GB2475633B (en) * | 2006-12-22 | 2011-10-05 | Wolfson Microelectronics Plc | Audio amplifer circuit and electronic apparatus including the same |
GB2478457B (en) | 2006-12-22 | 2011-12-07 | Wolfson Microelectronics Plc | Charge pump circuit and methods of operation thereof |
GB2447426B (en) * | 2006-12-22 | 2011-07-13 | Wolfson Microelectronics Plc | Charge pump circuit and methods of operation thereof |
KR20100014298A (en) * | 2007-01-12 | 2010-02-10 | 클리포드 더블유. 랫쇼 | Electronic bass register musical instrument tube preamplifier |
TWI382654B (en) * | 2007-02-16 | 2013-01-11 | Realtek Semiconductor Corp | Driver amplifier circuit and method thereof |
JP2008244623A (en) * | 2007-03-26 | 2008-10-09 | Matsushita Electric Ind Co Ltd | Semiconductor integrated circuit |
GB0715254D0 (en) * | 2007-08-03 | 2007-09-12 | Wolfson Ltd | Amplifier circuit |
WO2009022196A1 (en) * | 2007-08-13 | 2009-02-19 | Freescale Semiconductor, Inc. | Voltage supply circuitry and integrated corcuit therefor |
US8179372B1 (en) | 2007-10-01 | 2012-05-15 | Integrated Device Technology, Inc. | Electronic display with array context-sensitive search (ACS) technology |
US7733178B1 (en) | 2007-10-24 | 2010-06-08 | Fairchild Semiconductor Corporation | High efficiency audio amplifier |
US7750732B1 (en) | 2007-12-04 | 2010-07-06 | Fairchild Semiconductor Corporation | Adaptive rail amplifier (ARA) technology |
US7937109B2 (en) | 2008-01-24 | 2011-05-03 | Hewlett-Packard Development Company, L.P. | Current source driver for common ground signal interface |
US7612615B1 (en) | 2008-06-12 | 2009-11-03 | Mediatek Inc. | Dual supply amplifier |
WO2010032589A1 (en) * | 2008-09-17 | 2010-03-25 | 旭化成エレクトロニクス株式会社 | Charge pump circuit and semiconductor integrated circuit |
TW201043049A (en) * | 2008-12-15 | 2010-12-01 | Mediatek Inc | DC-coupled audio out unit |
US8325940B2 (en) | 2008-12-19 | 2012-12-04 | Conexant Systems, Inc. | Power management controller for drivers |
US7830209B1 (en) | 2009-01-19 | 2010-11-09 | Cirrus Logic, Inc. | Signal level selected efficiency in a charge pump power supply for a consumer device audio power output stage |
US7808324B1 (en) | 2009-03-17 | 2010-10-05 | Cirrus Logic, Inc. | Operating environment and process position selected charge-pump operating mode in an audio power amplifier integrated circuit |
US8000113B2 (en) * | 2009-04-07 | 2011-08-16 | Maxim Integrated Products, Inc. | Efficient power regulation for class-E amplifiers |
US8093951B1 (en) | 2009-04-14 | 2012-01-10 | Cirrus Logic, Inc. | Pulse-width modulated (PWM) audio power amplifier having output signal magnitude controlled pulse voltage and switching frequency |
JP5343786B2 (en) * | 2009-09-18 | 2013-11-13 | ヤマハ株式会社 | Amplification equipment |
JP5333111B2 (en) * | 2009-09-18 | 2013-11-06 | ヤマハ株式会社 | Amplification equipment |
US8339186B2 (en) | 2009-12-30 | 2012-12-25 | Diodes Incorporated | Voltage level shift circuits and methods |
US8593830B2 (en) | 2010-06-29 | 2013-11-26 | Maxim Integrated Products, Inc. | Reverse current limit protection for active clamp converters |
CN101931375A (en) | 2010-08-26 | 2010-12-29 | 成都芯源系统有限公司 | Amplifying circuit with high power supply rejection ratio |
TWI508437B (en) | 2013-01-25 | 2015-11-11 | Richtek Technology Corp | Voltage adjusting circuit for amplifier circuit and method thereof |
EP3193436B1 (en) * | 2016-01-15 | 2019-10-30 | Nxp B.V. | Charge pump circuit driving a load connection switch |
CN109688514B (en) * | 2018-12-26 | 2023-09-15 | 上海艾为电子技术股份有限公司 | High-voltage digital audio power amplifier system |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5289137A (en) * | 1991-12-31 | 1994-02-22 | Texas Instruments Incorporated | Single supply operational amplifier and charge pump device |
US5666355A (en) * | 1994-07-21 | 1997-09-09 | Interdigital Technology Corporation | Power consumption control method and apparatus for a communication system subscriber unit |
US6011440A (en) * | 1997-03-18 | 2000-01-04 | Linear Technology Corporation | Amplifier having output range that exceeds supply voltage |
Family Cites Families (38)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4966057A (en) | 1972-10-27 | 1974-06-26 | ||
US4456887A (en) | 1980-09-25 | 1984-06-26 | Pioneer Electronic Corporation | Differential amplifier |
JPS6179310A (en) | 1984-09-27 | 1986-04-22 | Matsushita Electric Ind Co Ltd | Output limiter of power amplifier |
JPH0775289B2 (en) | 1986-03-03 | 1995-08-09 | 株式会社日立製作所 | Transconductance amplifier circuit |
US4780625A (en) | 1987-05-12 | 1988-10-25 | Motorola, Inc. | Integrated circuit sensor circuit |
JPH01117423A (en) | 1987-10-30 | 1989-05-10 | Alpine Electron Inc | Digital analog converter |
JPH0828630B2 (en) | 1988-01-21 | 1996-03-21 | 日本電気株式会社 | Operational amplifier circuit |
JPH0472902A (en) | 1990-07-13 | 1992-03-06 | Fujitsu Ten Ltd | Controller for on-vehicle ic having standby switch |
US5122759A (en) | 1990-10-25 | 1992-06-16 | Texas Instruments Incorporated | Class-A differential amplifier and method |
JPH0558227A (en) * | 1991-08-30 | 1993-03-09 | Fujitsu Ten Ltd | On-vehicle audio system |
US5280235A (en) | 1991-09-12 | 1994-01-18 | Texas Instruments Incorporated | Fixed voltage virtual ground generator for single supply analog systems |
JPH05226940A (en) | 1992-02-15 | 1993-09-03 | Rohm Co Ltd | Amplifier circuit |
JPH0677763A (en) | 1992-06-17 | 1994-03-18 | Texas Instr Inc <Ti> | Method and apparatus for termination of transmission line |
JPH06188660A (en) | 1992-12-16 | 1994-07-08 | Nec Eng Ltd | Power amplifier circuit |
US5412309A (en) | 1993-02-22 | 1995-05-02 | National Semiconductor Corporation | Current amplifiers |
US5625278A (en) | 1993-06-02 | 1997-04-29 | Texas Instruments Incorporated | Ultra-low drop-out monolithic voltage regulator |
US5410273A (en) | 1993-11-01 | 1995-04-25 | Advanced Micro Devices | Low distortion operational amplifier |
JPH07184370A (en) * | 1993-12-24 | 1995-07-21 | Rohm Co Ltd | Battery-driven acoustic device |
US5563526A (en) | 1994-01-03 | 1996-10-08 | Texas Instruments Incorporated | Programmable mixed-mode integrated circuit architecture |
US5422600A (en) * | 1994-06-23 | 1995-06-06 | Motorola, Inc. | Amplifier input stage with charge pump supplying a differential transistor pair |
US5469106A (en) * | 1994-10-25 | 1995-11-21 | Elantec, Inc. | Voltage controlled amplifier which reduces differential gain |
JP2731751B2 (en) | 1995-07-17 | 1998-03-25 | 有限会社井藤電機鉄工所 | Headphone equipment |
US5736899A (en) * | 1996-05-15 | 1998-04-07 | Bowers; Derek F. | Fully differential voltage controlled operational transconductance amplifier |
JPH09326642A (en) | 1996-06-06 | 1997-12-16 | Mitsubishi Electric Corp | Integrated circuit device |
US5903185A (en) * | 1996-12-20 | 1999-05-11 | Maxim Integrated Products, Inc. | Hybrid differential pairs for flat transconductance |
US5880638A (en) * | 1997-03-20 | 1999-03-09 | Maxim Integrated Products | Rail-to-rail operational amplifier and method for making same |
US6472935B2 (en) | 1998-03-26 | 2002-10-29 | Maxim Integrated Products, Inc. | Combining networks for switchable path power amplifiers |
WO2000013308A1 (en) | 1998-08-31 | 2000-03-09 | Maxim Integrated Products, Inc. | Linear and multi-sinh transconductance circuits |
US6166603A (en) * | 1998-12-02 | 2000-12-26 | Maxim Integrated Products, Inc. | Class-ab output stages with improved distortion performance |
US6163216A (en) * | 1998-12-18 | 2000-12-19 | Texas Instruments Tucson Corporation | Wideband operational amplifier |
US6512411B2 (en) | 1999-08-05 | 2003-01-28 | Maxim Integrated Products, Inc. | Charge pump mode transition control |
JP2001309400A (en) * | 2000-04-19 | 2001-11-02 | Sony Corp | Integrated circuit |
US6452455B2 (en) | 2000-07-21 | 2002-09-17 | Texas Instruments Incorporated | Capacitor bias recovery methodology |
US6487034B1 (en) | 2001-06-08 | 2002-11-26 | Texas Instruments Incorporated | Write head fault detection with small threshold |
JP4011317B2 (en) * | 2001-09-12 | 2007-11-21 | シャープ株式会社 | Constant voltage circuit and infrared remote control receiver using the same |
US7061327B2 (en) | 2002-01-24 | 2006-06-13 | Maxim Integrated Products, Inc. | Single supply headphone driver/charge pump combination |
US7183857B2 (en) | 2002-01-24 | 2007-02-27 | Maxim Integrated Products Inc. | Single supply direct drive amplifier |
JP2004135016A (en) * | 2002-10-10 | 2004-04-30 | Sharp Corp | Output muting circuit of audio equipment |
-
2005
- 2005-01-18 US US11/039,386 patent/US7183857B2/en not_active Expired - Lifetime
- 2005-07-29 EP EP05818194A patent/EP1771943B1/en active Active
- 2005-07-29 JP JP2007505288A patent/JP2007531419A/en active Pending
- 2005-07-29 AT AT05818194T patent/ATE466401T1/en not_active IP Right Cessation
- 2005-07-29 EP EP10161051A patent/EP2204904A3/en not_active Withdrawn
- 2005-07-29 EP EP10015185A patent/EP2296267A3/en not_active Ceased
- 2005-07-29 WO PCT/US2005/027148 patent/WO2006031304A2/en active Application Filing
- 2005-07-29 TW TW094125764A patent/TWI311399B/en not_active IP Right Cessation
- 2005-07-29 DE DE602005020937T patent/DE602005020937D1/en active Active
-
2007
- 2007-02-26 US US11/711,480 patent/US20070229169A1/en not_active Abandoned
-
2008
- 2008-05-06 US US12/116,144 patent/US7714661B2/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5289137A (en) * | 1991-12-31 | 1994-02-22 | Texas Instruments Incorporated | Single supply operational amplifier and charge pump device |
US5666355A (en) * | 1994-07-21 | 1997-09-09 | Interdigital Technology Corporation | Power consumption control method and apparatus for a communication system subscriber unit |
US6011440A (en) * | 1997-03-18 | 2000-01-04 | Linear Technology Corporation | Amplifier having output range that exceeds supply voltage |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060183509A1 (en) * | 2005-02-16 | 2006-08-17 | Shuyong Shao | DC power source for an accessory of a portable communication device |
US20070202854A1 (en) * | 2006-01-13 | 2007-08-30 | Samsung Electronics Co., Ltd. | Terminal apparatus and method for providing media transmission time information in a PoC system and PoC system for the same |
US7787868B2 (en) * | 2006-01-13 | 2010-08-31 | Samsung Electronics Co., Ltd | Terminal apparatus and method for providing media transmission time information in a PoC system and PoC system for the same |
US20080144857A1 (en) * | 2006-12-19 | 2008-06-19 | Shih-Hang Huang | Audio signal output circuit capable of decreasing pop noise |
US20080159567A1 (en) * | 2006-12-22 | 2008-07-03 | Lesso John P | Audio amplifier circuit and electronic apparatus including the same |
US8363856B2 (en) * | 2006-12-22 | 2013-01-29 | Wolfson Microelectronics ple | Audio amplifier circuit and electronic apparatus including the same |
US7932706B2 (en) | 2007-01-10 | 2011-04-26 | Semiconductor Components Industries, Llc | Single input dual output voltage power supply and method therefor |
US20090302950A1 (en) * | 2007-01-10 | 2009-12-10 | Alexandre Pujol | Single input dual output voltage power supply and method therefor |
US20110206942A1 (en) * | 2008-09-16 | 2011-08-25 | Patrick Schiebel | Connections Between a Monolithic Metal Component and a Continuous-Fiber Reinforced Laminate Component, and Method for Production of the Same |
US8471628B2 (en) | 2008-10-21 | 2013-06-25 | Semiconductor Components Industries, Llc | Amplifier with reduced output transients and method therefor |
WO2010142460A1 (en) * | 2009-06-12 | 2010-12-16 | St-Ericsson Sa | Circuit for an amplifier |
EP2262106A1 (en) | 2009-06-12 | 2010-12-15 | ST-Ericsson SA | Circuit for an amplifier |
CN102484457A (en) * | 2009-06-12 | 2012-05-30 | 意法爱立信有限公司 | Circuit for an amplifier |
US8659350B2 (en) | 2009-06-12 | 2014-02-25 | St-Ericsson Sa | Circuit for an amplifier |
US20140086432A1 (en) * | 2011-12-16 | 2014-03-27 | Ipgoal Microelectronics (Sichuan) Co., Ltd. | POP noise suppression circuit and system |
US9130516B2 (en) * | 2011-12-16 | 2015-09-08 | Ipgoal Microelectronics (Sichuan) Co., Ltd. | POP noise suppression circuit and system |
Also Published As
Publication number | Publication date |
---|---|
ATE466401T1 (en) | 2010-05-15 |
WO2006031304A3 (en) | 2007-05-03 |
EP1771943A4 (en) | 2008-06-11 |
EP2204904A3 (en) | 2010-10-27 |
US7714661B2 (en) | 2010-05-11 |
EP2204904A2 (en) | 2010-07-07 |
JP2007531419A (en) | 2007-11-01 |
DE602005020937D1 (en) | 2010-06-10 |
TW200620814A (en) | 2006-06-16 |
EP1771943A2 (en) | 2007-04-11 |
EP1771943B1 (en) | 2010-04-28 |
US7183857B2 (en) | 2007-02-27 |
TWI311399B (en) | 2009-06-21 |
WO2006031304A2 (en) | 2006-03-23 |
US20080273120A1 (en) | 2008-11-06 |
US20050184807A1 (en) | 2005-08-25 |
EP2296267A3 (en) | 2011-04-13 |
EP2296267A2 (en) | 2011-03-16 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7714661B2 (en) | Single supply direct drive amplifier | |
US7061327B2 (en) | Single supply headphone driver/charge pump combination | |
JP5934759B2 (en) | Charge pump circuit and operation method thereof | |
US8295512B2 (en) | Microphone with voltage pump | |
CN112042117A (en) | Class D amplifier with multiple independent output stages | |
US8552788B2 (en) | Apparatus and methods for adaptive common-mode level shifting | |
US20120189139A1 (en) | Semiconductor Integrated Circuit Having a Switched Charge Pump Unit and Operating Method Thereof | |
US20230030111A1 (en) | Driver circuitry | |
EP1193867A2 (en) | Digital amplifier | |
US8610492B2 (en) | High voltage tolerant inverting charge pump | |
US10630173B2 (en) | Negative charge pump and audio ASIC with such negative charge pump | |
CN110324770B (en) | Microphone, integrated circuit thereof and electronic equipment | |
US6456140B1 (en) | Voltage level translation circuits | |
CN209914063U (en) | Microphone, integrated circuit thereof and electronic equipment | |
US6762641B1 (en) | Voltage level translation circuits | |
CN114982127A (en) | Switching amplifier |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |
|
AS | Assignment |
Owner name: LEAR CORPORATION, MICHIGAN Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:JPMORGAN CHASE BANK, N.A.;REEL/FRAME:032722/0553 Effective date: 20100830 |