Patent application number | Description | Published |
20110130984 | ESTIMATING REMAINING BATTERY SERVICE LIFE IN AN IMPLANTABLE MEDICAL DEVICE - Methods for estimating a remaining service life of an implantable medical device (IMD) battery are presented. In one embodiment, a characteristic discharge model of the battery is employed. Systems employing the methods may include an external device coupled to the IMD, for example, via a telemetry communications link, wherein a first portion of a computer readable medium included in the IMD is programmed to provide instructions for the measurement, or tracking, of time and the measurement of battery voltage, and a second portion of the computer readable medium included in the external device is programmed to provide instructions for carrying out the calculations when the voltage and time data is transferred via telemetry from the IMD to the external device. | 06-02-2011 |
20120010672 | BATTERY LONGEVITY ESTIMATOR THAT ACCOUNTS FOR EPISODES OF HIGH CURRENT DRAIN - System and method for estimating a remaining capacity of a battery of an implantable medical device. The implantable medical device has a battery producing a current and having a remaining battery capacity, the implantable medical device being configured to utilize a relatively low amount of the current and, in specific instances, a relatively large pulse of the current. The processor is coupled to the battery and configured to calculate an estimate of the remaining battery capacity based, at least in part, on a measured battery parameter and occurrences of the specific instances of delivery of the relatively large pulse of the current. | 01-12-2012 |
20120105017 | METHOD OF MAINTAINING WET-TANTALUM ELECTROLYTIC CAPACITORS - Wet-tantalum capacitors used in a medical device are charged to and maintained at a maintenance voltage between full energy charges so that deformation in the wet-tantalum capacitor is substantially inhibited. | 05-03-2012 |
20130226256 | BATTERY LONGEVITY ESTIMATOR THAT ACCOUNTS FOR EPISODES OF HIGH CURRENT DRAIN - System and method for estimating a remaining capacity of a battery of an implantable medical device. The implantable medical device has a battery producing a current and having a remaining battery capacity, the implantable medical device being configured to utilize a relatively low amount of the current and, in specific instances, a relatively large pulse of the current. The processor is coupled to the battery and configured to calculate an estimate of the remaining battery capacity based, at least in part, on a measured battery parameter and occurrences of the specific instances of delivery of the relatively large pulse of the current. | 08-29-2013 |
Patent application number | Description | Published |
20100157498 | Current Detection and Limiting Method and Apparatus - An apparatus for detecting and controlling current. A current detector for generating a first value that represents an amount of current being delivered to a device. A current limit circuit for generating a second value that represents a maximum permitted current level from a current source. A current controller for controlling the amount of current drawn by the device if the first value exceeds the second value. | 06-24-2010 |
20100158278 | Power Management Controller for Drivers - A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods. | 06-24-2010 |
20100214000 | Systems and Methods for Driving High Power Stages Using Lower Voltage Processes - In today's environment class-D amplifiers are used to provide an integrated solution for applications such as powered audio devices due to their advantages in power consumption and size over more traditional analog amplifiers. Due to power output requirements, the output stages of power drivers such as class-D amplifiers require a supply voltage in excess of the technologically allowed voltage for the switches in the output stage. A level shifter is used to ensure voltages supplied to the output switches do not exceed the technological limits. An ideal level shifter should provide the optimal voltage swing to output switches under all process, supply voltage and temperature (PVT) variations. The ideal level shifter should also provide fast transitions when the control signal changes from high to low and low to high. | 08-26-2010 |
20100321112 | Anti-Pop Circuit - Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier. | 12-23-2010 |
20110050467 | Noise-Shaped Scrambler for Reduced Out-of-Band Common-Mode Interference - Class-D amplifiers have evolved from using binary pulse-width modulation (PWM) modulators to three-level PWM modulators. Three-level PWM drivers for audio applications offer the benefits of eliminating costly elements at the output of an audio system. However, they also introduce increased common-mode interference. Three-level PWM generates three states, but one state has two interchangeable representations which can be scrambled in order to shape the common-mode output spectrum. | 03-03-2011 |
20110080191 | System and Method for Clock-Synchronized Triangular Waveform Generation - A triangular waveform generator is converted to a free running oscillator controlled by a calibration code. The free running oscillator can be synchronized to an external clock signal by comparing the external clock frequency to the frequency of the triangular waveform and adjusting the calibration code until the discrepancy in frequency is minimized. | 04-07-2011 |
20110087346 | Tuning and DAC Selection of High-Pass Filters for Audio Codecs - An integrated audio codec includes a high-pass filter to prevent damage to personal computer speakers and other components. The audio codec may be compliant with HD audio standards and can operate with generic software drivers. Tuning of the high-pass filter is provided through an external pin-out where either an external capacitor or external resistors provide an ability to tune the high-pass filter. In one implementation, a tuning voltage is digitized into a tuning code used by a digital high-pass filter. In addition, multiplexers can be used to insure only the audio path leading to the speakers is filtered. | 04-14-2011 |
20110123049 | Systems and Methods for Offset Cancellation Method for DC-Coupled Audio Drivers - Direct current (DC) offset in and audio driver can cause a constant drain on power even when there is no sound. Furthermore it can cause an audible pop when the audio driver is enabled. A scaled replica output stage can be employed to perform DC offset cancellation offline during a sampling phase. Once DC offset cancellation is achieved, the audio driver uses a full scale output stage during the operation phase. | 05-26-2011 |
20110156793 | SYSTEMS AND METHODS FOR DRIVING HIGH POWER STATES USING LOWER VOLTAGE PROCESSES - A battery assisted level shifter comprises a pull up transistor pulling up an output when a received input signal is high, a pull down transistor pulling down the output when the received input signal is low, and a battery element to provide voltage offsets. The battery element can be implemented using one or more pull-up transistors for assisting with pulling up the output. The level shifter can be used in class-D amplifiers, DC-DC power converters and interfaces between circuits having different reference voltages. | 06-30-2011 |
20120001613 | HIGH-BANDWIDTH LINEAR CURRENT MIRROR - High linearity is essential in audio circuitry. As sampling rates for audio applications are needed, high speed and high linearity are needed in analog and mixed signal portions of audio circuitry such as in current mirrors. A current mirror employs two current paths in an output. The first current path is driven by a fast acting transistor through a resistor. The second current path is driven by a differential amplifier coupled to another transistor through another resistor. The second current path is used to maintain linearity by causing the voltage across both transistors to be the same. | 01-05-2012 |
20120002821 | GROUNDING SWITCH METHOD AND APPARATUS - A grounding switch is described which operates properly even in the presence of negative voltages on a signal line. The grounding switch uses isolated field effect transistors that have their substrates tied to different voltages. The isolated field effect transistor has a gate voltage and substrate voltage which can be pulled down to a negative voltage when the signal line has a negative voltage allowing the switch to remain open even with a negative voltage. | 01-05-2012 |
20120044023 | Apparatus and Method for a Smooth Powerup of a Reference Signal - A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one or more current mirrors where the newly mirrored current can be squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can be used to charge a capacitor which is used to provide the reference voltage. | 02-23-2012 |
20120062320 | ANTI-POP CIRCUIT - Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier. | 03-15-2012 |
20120313712 | APPARATUS AND METHOD FOR A SMOOTH POWERUP OF A REFERENCE SIGNAL - A circuit for providing a reference voltage can be widely used in audio applications. However, at startup an abrupt start in the reference signal can cause undesirable audible artifacts. A circuit employing feedback of a reference voltage to control the charging of a capacitor which provides the reference voltage can be used to provide a smooth startup to the reference voltage. The circuit contains a differential pair for steering a fixed current source from one path to another as the reference voltage increases. The steered current can then be mirrored into one ore more current mirrors where the newly mirrored current can he squeezed to zero when the difference between a desired reference voltage and the reference voltage approaches zero. This newly mirrored current can he used to charge a capacitor which is used to provide the reference voltage. | 12-13-2012 |
20130034237 | MULTIPLE MICROPHONE SUPPORT FOR EARBUD HEADSETS - A system for improved audio in a headset comprising a first headset microphone generating a first signal. A second headset microphone generating a second signal. A multiplexer coupled to the first headset microphone and the second headset microphone for multiplexing the first signal and the second signal. A power extractor for extracting power for use by one or more of the multiplexer, the first headset microphone and the second headset microphone. A demultiplexer for extracting the first signal and the second signal. A signal processor for generating a noise reduced microphone signal. An audio subsystem for receiving the noise reduced microphone signal and for generating speaker signals for a first headphone speaker and a second headphone speaker. | 02-07-2013 |
20130094661 | POWER MANAGEMENT CONTROLLER FOR DRIVERS - A driver controller comprising a state machine for controlling transitions between a plurality of states. An output switch for providing a low impedance path to ground during transition periods. An output stage for decoupling output signal from driver amplifier during the transition periods. | 04-18-2013 |
20130113541 | LOW POWER LEVEL SHIFTER WITH OUTPUT SWING CONTROL - A level shifter comprising a first driver transistor receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value. | 05-09-2013 |
20130141071 | SYSTEM AND METHOD FOR CAPACITIVE DC-DC CONVERTER WITH VARIABLE INPUT AND OUTPUT VOLTAGES - A capacitive voltage converter comprising a switched capacitor array having a voltage input and a voltage output. A skip gating control coupled to the switched capacitor array and configured to control a switching activity of the switched capacitor array. A resistance look-up table coupled to the switched capacitor array and configured to control a resistance value of the switched capacitor array. | 06-06-2013 |
20130141829 | CURRENT DETECTION AND LIMITING METHOD AND APPARATUS - An apparatus for detecting and controlling current. A current detector for generating a first value that represents an amount of current being delivered to a device. A current limit circuit for generating a second value that represents a maximum permitted current level from a current source. A current controller for controlling the amount of current drawn by the device if the first value exceeds the second value. | 06-06-2013 |
20130142350 | MULTI-STANDARD HEADSET SUPPORT WITH INTEGRATED GROUND SWITCHING - A system for detecting a jack configuration comprising a first plurality of switches configured to couple a first headphone jack position to ground. A second plurality of switches configured to couple a second headphone jack position to ground. A microphone bias circuit for applying a microphone bias signal to the second headphone jack position when the first headphone jack position is coupled to ground, and for applying the microphone bias signal to the first headphone jack position when the second headphone jack position is coupled to ground. | 06-06-2013 |
20130257176 | METHODS TO REDUCE CURRENT SPIKES IN CAPACITIVE DC-DC CONVERTERS EMPLOYING GAIN-HOPPING - A capacitive voltage converter providing multiple gain modes comprising a switched capacitor array having a voltage input and a voltage output. A skip gating control coupled to the switched capacitor array and configured to control a switch resistance value of the switched capacitor array, and to control a switching sequence of the switched capacitor array. An override control coupled to the skip gating control and the switched capacitor array, the override control configured to detect transitions in a gain mode and to modify the switch resistance value of the switched capacitor array and the switching sequence of the switched capacitor array for a finite amount of time following the gain mode transition. | 10-03-2013 |
20140003621 | GROUNDING SWITCH METHOD AND APPARATUS | 01-02-2014 |
20140029770 | HYBRID ANALOG/DIGITAL HEADSET - A device comprising a detector configured to receive an indication from a terminal of a connector and to determine whether the indication matches an expected result. One or more first switches are configured to connect one or more speaker transducers to the connector if the indication is false. One or more second switches are configured to connect the one or more speaker transducers to a digital output converter if the indication is true. The device can also include one or more third switches configured to connect one or more microphone elements to the connector if the indication is false, and one or more fourth switches configured to connect one or more microphones to a digital input converter if the indication is true. The input and output converters can be stand alone or part of a digital signal processor. | 01-30-2014 |
20140176223 | LOW POWER LEVEL SHIFTER WITH OUTPUT SWING CONTROL - A level shifter comprising a first driver transistor for receiving an input signal. A gate-controlled transistor coupled to the first driver transistor. A second driver transistor coupled to the gate controlled transistor. An output coupled to the second driver transistor, wherein the gate-controlled transistor is for receiving a predetermined gate voltage when the output voltage exceeds a predetermined value. | 06-26-2014 |
20140247091 | ADAPTIVE BIASING TECHNIQUE FOR AUDIO CIRCUITRY - A circuit comprising a peak detector configured to receive a positive voltage input, a negative voltage input and a reference current source input and to output a peak signal data value. A fast attack current source control coupled to the peak detector and configured to generate a current source control signal as a function of the peak signal data value. A slow decay control coupled to the fast attack current source control and configured to reduce the current source control signal based on a predetermined or user-selected decay rate. A variable current source coupled to the fast attack current source control and configured to generate a variable current as a function of the current source control signal. Amplifier circuitry coupled to the variable current source, the amplifier circuitry configured to receive the variable current. | 09-04-2014 |