Mediatek Corporation

Sung-Han Wen

Kuan-Ta Chen

Chuan-Hung Hsiao

Yu-Cheng Chang

Shih-Hsiung Chien

Po-Yi Lee

Chien-Chung Yang

Chen-Chien Lin

Chien-Ming Chen

Yu-Hung Lin

Yen-Hsun Hsu

Wei-Cheng Tang

Hung-I Chen

Jou Lee

Wei-Hao Sun

Chi-Heng Chung

Satya Narayana Ganta

Sujith Kumar Billa

Ya-Chi Chen

Ying-Wei Chou

Chun-Yuan Cheng

Chin-Yuan Chang

Yu-cheng Chang

A tri-level digital-to-analog converter (DAC) element includes a first DAC cell. The first DAC cell includes a first reference circuit, a second reference circuit, and a switch circuit. The first reference circuit provides a first reference signal. The second reference circuit provides a second reference signal. The first switch circuit receives a control input from an input port of the tri-level DAC element, and controls interconnection between the first reference circuit, the second reference circuit, and an output port of the tri-level DAC element according to the control input. During a period in which the tri-level DAC element operates in a '0' state, the first switch circuit is arranged to couple at least one of the first reference circuit and the second reference circuit to the output port of the tri-level DAC element.

Tri-level digital-to-analog converter element with mismatch suppression and associated method

The present invention provides a linear amplifier including an amplifier stage, a DC-shifting stage, a compensation network and a power stage. The amplifier stage is configured to generate a first signal and a second signal. The DC-shifting stage is configured to adjust a DC voltage of the first signal and a DC voltage of the second signal to generate an adjusted first signal and an adjusted second signal. The compensation network is configured to generate a first driving signal and a second driving signal according to the first signal, the second signal, the adjusted first signal and the adjusted second signal. The power stage is configured to generate an output signal according to the first driving signal and the second driving signal.

Amplifier output stage with DC-shifting circuit for high-speed supply modulator

The present invention provides an amplifier including an input stage, an amplifier stage, a power stage and a de-gain stage. The input stage is configured to receive an input signal to generate an amplified signal. The amplifier stage is configured to generate a first driving signal and a second driving signal according to the amplified signal. The power stage comprises a first input terminal and a second input terminal, wherein the power stage is coupled to a supply voltage and a ground voltage, for receiving the first driving signal and the second driving signal from the first input terminal and the second input terminal, respectively, and generating an output signal.

High-efficiency amplifier architecture with de-gain stage

A noise filter circuit includes a filter and a transistor off-resistance control circuit. The filter includes a first transistor and a charge storage component. The first transistor has off-resistance when turned off or operated under sub-threshold region. A control terminal of the first transistor is not directly tied to a reference voltage, and is used to receive a first control voltage. The charge storage component has one terminal coupled to a connection terminal of the first transistor. The transistor off-resistance control circuit is coupled to the first transistor, and arranged to set the first control voltage for controlling the off-resistance of the first transistor.

Noise filter circuit with controllable transistor off-resistance and associated noise filtering method

A digital-to-analog converter (DAC) includes a plurality of DAC cells, a mismatch error sorting circuit, and a dynamic element matching (DEM) circuit. The mismatch error sorting circuit generates a sorting result of the plurality of DAC cells according to mismatch error levels of the plurality of DAC cells. The DEM circuit shapes the mismatch error levels of the plurality of DAC cells according to the sorting result of the plurality of DAC cells.

Digital-to-analog converter with sorting of unit cells that is based on mismatch errors and/or selection of new pointer location that is based on utilization rates of unit cells and associated method

The present invention provides an amplifier circuit, wherein the amplifier circuit includes an input terminal, a capacitor, an amplifier, a feedback circuit and an aliasing tone cancellation circuit. The input terminal is configured to receive a first input signal. The capacitor is coupled to the input terminal. The amplifier is configured to receive the input signal through the capacitor to generate an output signal. The feedback circuit is coupled between an input node and an output node of the amplifier, and is configured to generate a feedback signal according to the output signal, wherein the feedback circuit includes a storage block including a switched-capacitor. The aliasing tone cancellation circuit is coupled between the input terminal of the amplifier circuit and the input node of the amplifier, and configured to generate a signal to cancel or reduce an aliasing tone of the feedback signal according to the input signal.

DC-blocking amplifier with aliasing tone cancellation circuit

An amplifier circuit includes a voltage-to-current conversion circuit and a current-to-voltage conversion circuit. The voltage-to-current conversion circuit generates a current signal according to an input voltage signal, and includes an operational transconductance amplifier (OTA) used to output the current signal at an output port of the OTA. The current-to-voltage conversion circuit generates an output voltage signal according to the current signal, and includes a linear amplifier (LA), wherein an input port of the LA is coupled to the output port of the OTA, and the output voltage signal is derived from an output signal at an output port of the LA.

Amplifier circuit using voltage-to-current conversion and associated envelope tracking supply modulator using the same

A high-linearity amplifier including a main operational amplifier, a feedback circuit, and a compensation circuit is shown. The feedback circuit couples an output signal of the main operational amplifier to an input port of the main operational amplifier. The compensation circuit couples a former-stage circuit of the amplifier to the input port of the main operational amplifier to compensate for the non-linearity of the feedback circuit. The compensation circuit and the feedback circuit form an inverse paralleling linearization architecture. In the inverse paralleling linearization architecture, a resistor in the feedback circuit corresponds to a resistor in the compensation circuit which is biased in an inversed way in comparison with the corresponding resistor in the feedback circuit.

High-linearity amplifier

A high-linearity amplifier including a main operational amplifier, a feedback circuit, and a compensation circuit is shown. The feedback circuit couples an output signal of the main operational amplifier to an input port of the main operational amplifier. The compensation circuit is coupled to the input port of the main operational amplifier to compensate for the non-linearity of the feedback circuit. A signal coupled to the input port of the main operational amplifier through the compensation circuit has an inverse phase compared to the output signal of the main operational amplifier.

A multi-stage amplifier with a high signal-to-noise ratio is introduced. Multiple amplification stages are cascaded between an input terminal and an output terminal of the amplifier. A controller switches the output stage among the multiple amplification stages from a normal mode to an attenuation mode in response to the amplifier input being lower than the threshold. In the attenuation mode, the output stage provides an attenuation resistor coupled in series with the load resistor of the amplifier. Noise is successfully attenuated by the attenuation-mode output stage.

High signal-to-noise ratio amplifier with multiple output modes

The present invention provides an amplifier including a DAC, an analog signal processing circuit, a digital signal processing circuit, a signal detector and a driving stage is disclosed. The DAC is configured to perform a digital-to-analog conversion operation on a digital input signal to generate an analog input signal. The analog signal processing circuit is configured to generate a first processed signal according to the analog input signal and a feedback signal. The digital signal processing circuit is configured to process the digital input signal to generate a second processed signal. The signal detector is configured to detect strength of the digital input signal to generate a mode selection signal. The driving stage is configured to refer to the mode selection signal to receive one of the first processed signal and the second processed signal to generate an output signal, wherein the feedback signal is generated by the output signal.

Amplifier with signal dependent mode operation

An amplifier circuit with in-band gain degradation compensation is shown. The amplifier circuit has an input-stage amplifier, at least one intermediate-stage amplifier, and an output-stage amplifier cascaded between an input port and an output port of the amplifier circuit. A compensation capacitor is coupled between the output port of the amplifier circuit and an output port of the input-stage amplifier. A high-order damping circuit is coupled to an output port of the intermediate-stage amplifier.

Amplifier circuit with high-order damping circuit and the high-order damping circuit

The present invention provides a circuit having a filter with an amplifier circuit for filtering and amplifying an input signal to generate an output signal, wherein a corner frequency of the filter is adjustable to control a settling time of the output signal.

Circuit having high-pass filter with variable corner frequency

A digital-to-analog conversion circuit is used for converting a first digital input into a first analog output, and includes a segmentation circuit, a plurality of multi-bit dynamic element matching digital-to-analog converters (DEM DACs), and a combination circuit. The segmentation circuit applies segmentation to the first digital input to generate a plurality of code segments. The multi-bit DEM DACs convert the code segments into a plurality of DAC outputs, respectively, wherein the multi-bit DEM DACs include at least a first multi-bit DEM DAC and a second multi-bit DEM DAC, and the first multi-bit DEM DAC and the second multi-bit DEM DAC employ different DEM techniques. The combination circuit combines the DAC outputs to generate the first analog output.

High linearity digital-to-analog converter with ISI-suppressing method

The present invention provides a class-G amplifier, wherein the class-G amplifier includes an amplifier stage, an impedance detector and a power source. In the operations of the class-G amplifier, the amplifier stage is supplied by a supply voltage, and amplifies an input audio signal to generate an output audio signal, and the impedance detector is configured to detect an output impedance of the amplifier stage to generate a detection result, and the power source refers to the detection result to determine a level and a switching frequency of the supply voltage.

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Taipei, Taiwan

Sung-Han Wen