| 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 |
| 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 |
