| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 330086000 | Variable impedance in feedback path varied by separate control path | 14 |
| 20090009242 | LINE DRIVER CAPABLE OF AUTOMATICALLY ADJUSTING OUTPUT IMPEDANCE - A line driver includes: a differential amplifier for amplifying an input signal to generate an output signal; first and second series resistors coupled respectively to output terminals of the differential amplifier and through which the output signal is output; first and second negative-feedback resistors each coupled between a respective input terminal and a respective output terminal of the differential amplifier; first and second positive-feedback variable resistors each coupled between a respective input terminal of the differential amplifier and a respective one of the first and second series resistors; and an adjusting unit coupled to the first and second positive-feedback variable resistors to adjust a resistance thereof with reference to the output signal. | 01-08-2009 |
| 20090033413 | GAIN CONTROLLED AMPLIFIER AND CASCODED GAIN CONTROLLED AMPLIFIER BASED ON THE SAME - A gain controlled amplifier and a cascoded gain controlled amplifier based on the same are disclosed. The gain controlled amplifier includes an operational amplifier for amplifying an input signal, an input resistor connected to an input terminal of the operational amplifier, a feedback resistor connected to an output terminal of the operational amplifier, and a resistor circuit for providing voltages having different levels to the input terminal and the output terminal of the operational amplifier, respectively, according to a digital signal composed of specified bits. The gain controlled amplifier employs an R-2R ladder circuit controlled by a digital signal so as to obtain a gain that is in linear proportion to a decibel scale. Since the R-2R ladder circuit operates with a small resistance value, the chip size of the gain controlled amplifier can be reduced. | 02-05-2009 |
| 20090058520 | AMPLIFIER CIRCUIT - An amplifier circuit that is less likely to cause an error in a gain and a DC offset voltage and is suitable for reducing a size and power consumption is offered. A first resistor and a second resistor are connected in series between an input terminal and an output terminal. A third resistor and a fourth resistor are connected in series between a VREFL terminal and a VREFH terminal. A ratio of a resistance of the first resistor to a resistance of the second resistor is equal to a ratio of a resistance of the third resistor to a resistance of the fourth resistor. A voltage at a connecting node between the first resistor and the second resistor is applied to a first differential input terminal (−) of an operational amplifier, while either a voltage at a connecting node between the third resistor and the fourth resistor or VREFH is selectively applied to a second differential input terminal (+) of the operational amplifier. An output of the operational amplifier is outputted through the output terminal as well as being applied to the first differential input terminal through the second resistor that serves as a feedback resistor. | 03-05-2009 |
| 20090091383 | GAIN AMPLIFIER HAVING SWITCHED-CAPACITOR STRUCTURE FOR MINIMIZING SETTLING TIME - Provided is a gain amplifier having a switched-capacitor structure capable of minimizing settling time, in which an input capacitor is connected to an input terminal during a first clock sampling an input signal, and thus an output terminal of the amplifier is reset in advance to an estimated output voltage value rather than 0 by the input capacitor. Accordingly, the slight move of the output terminal of the amplifier is sufficient to settle to a desired value in an amplification mode, so that slewing time can be reduced, and as a result, overall settling time and power consumption can be minimized. | 04-09-2009 |
| 20090184762 | OPTIMIZED RESISTOR NETWORK FOR PROGRAMMABLE TRANSCONDUCTANCE STAGE - A voltage-to-current converter is provided. The voltage-to-current converter comprises an amplifier, a resistor network, an R-2R network, and switches. The amplifier has a first input node (which is an input signal), a second input node, and an output node. The resistor network is coupled to the output node of the amplifier, includes a plurality of resistors coupled in series with on another, and includes a plurality of first tap nodes. The R-2R network is coupled to the resistor network and includes a plurality of second tap nodes. Additionally, at least one switch is coupled between the second input node of the amplifier and each first tap node, and at least one switch is coupled between the second input node of the amplifier and each of the second tap nodes. | 07-23-2009 |
| 20090237156 | POWER AMPLIFIERS HAVING IMPROVED STARTUP LINEARIZATION AND RELATED OPERATING METHODS - Systems and methods are described for improving the startup linearization of a power amplifier. A bias network is provided to generate a bias signal during amplifier startup, and the amplifier is configured to produce an output signal in response to the input signal and the bias signal. A variable impedance is provided to couple the input signal and the output signal in parallel with the amplifier. A controller is configured to apply a weighting function to the variable impedance over at least a startup phase of the amplifier system. By applying a non-linear or other weighting function to the variable impedance during startup, the gain of the amplifier can be controlled to thereby extend a time period over which the output power of the amplifier increases in a generally linear manner toward an operating level. | 09-24-2009 |
| 20100090763 | AUTOMATIC GAIN CONTROL CIRCUIT - An automatic gain control circuit including a variable gain amplifier ( | 04-15-2010 |
| 20100102878 | PHYSICAL QUANTITY SENSOR - A physical quantity sensor includes a sensor element for converting a physical quantity applied from outside into an electric signal, a detection circuit for amplifying and detecting an output signal of the sensor element, and an adjusting circuit for adjusting the output signal from the detection circuit to a predetermined signal. The adjusting circuit has an amplifying circuit for amplifying the output signal from the detection circuit and a reference amplification circuit having an amplification ratio linked with the amplifying circuit. With this configuration, it is possible to change the amplification ratio of the amplifying circuit provided in the adjusting circuit in accordance with a power voltage. As a result, it is possible to realize a physical quantity sensor having stable sensor detection sensitivity and highly accurate ratiometric characteristic. | 04-29-2010 |
| 20110043279 | ELECTRONIC VOLUME CIRCUIT - An electronic volume circuit includes a first signal processing circuit and a second signal processing circuit that are cascaded together. The first signal processing circuit includes a first operational amplifier including an input terminal and an output terminal, one or more input resistors inputting one or more signals to the input terminal of the first operational amplifier, and a feedback resistor connected between the input terminal and the output terminal of the first operational amplifier. The second signal processing circuit includes a second operational amplifier including an input terminal and an output terminal, an input capacitor inputting a signal output from the first operational amplifier to the input terminal of the second operational amplifier, and a resistor and a capacitor connected in parallel between the input terminal and the output terminal of the second operational amplifier. | 02-24-2011 |
| 20110260789 | VARIABLE GAIN AMPLIFIER CIRCUIT - A variable gain amplifier circuit includes: an operational amplifier having a non-inverting input terminal applied with a predetermined voltage; a feedback resistor having one end connected to an inverting input terminal of the operational amplifier and the other end connected to an output terminal of the operational amplifier; and a variable resistor having one end applied with an input voltage and the other end connected to the inverting input terminal of the operational amplifier. | 10-27-2011 |
| 20120019318 | VARIABLE RESISTER HAVING RESISTANCE VARYING GEOMETRICALLY RATIO AND CONTROL METHOD THEREOF - Provided is an analog amplifier for amplifying an analog signal and an analog filter, and in particular, an apparatus and method for controlling gain and cutoff frequency of the variable gain amplifier and the variable cutoff frequency filter that is capable of changing the gain and cutoff frequency. The variable resister includes a plurality of resister segments in the variable resister and, when a plurality of resistance candidates for the variable resister are arranged in order of size, the resistance candidates form a geometric series. | 01-26-2012 |
| 20120218036 | OFFSET COMPONENT CANCELATION METHOD AND CIRCUIT - Techniques are disclosed for canceling an offset component (e.g., dc component or dc offset) in an amplifier circuit. For example, an apparatus comprises an amplifier circuit with an amplifier element and a feedback resistor network coupled between an output of the amplifier element and an input of the amplifier element. The apparatus also comprises a current source coupled to the feedback resistor network, the current source generating a current signal that generates a voltage in a first portion of the feedback resistor network that cancels an offset component present in an input signal received by the amplifier circuit. A second portion of the feedback resistor network may be adjustable so that a gain applied to the input signal is adjustable while the offset component is canceled from the input signal. One or more resistors in the feedback resistor network may be composed of the same or substantially similar material as one or more resistors associated with the current source. In such case, the voltage generated in the first portion of the feedback resistor network that cancels the offset component present in the input signal received by the amplifier circuit is independent of a temperature variation and/or a process variation. | 08-30-2012 |
| 20120249235 | LOW DISTORTION AMPLIFER - A variable gain amplifier circuit ( | 10-04-2012 |
| 20130120060 | Sigma-Delta Modulator Approach to Increased Volume Resolution in Audio Output Stages - A variable gain analog amplifier is described that uses pulse-density modulation in the form of a sigma-delta modulator (SDM) to produce a gain by modulating the selection of a switch that selects the amount of resistance in a negative feedback loop of the amplifier. The output of the SDM is dithered to increase the gain resolution of the analog amplifier, wherein the increased resolution produces a quiet, inaudible transition between changes in gain setting at an output of the variable gain amplifier and in addition produces a quiet, inaudible mixing and merging of audio signals.. | 05-16-2013 |
