Realtek Semiconductor Inc.

Chih-Chan Tu

Chih-Lung Chen

Ka-Un Chan

A temperature sensing circuit that includes a bandgap voltage generation circuit, a current mirror branch, a variable resistor, a comparator circuit, a control circuit and a temperature determining circuit. The bandgap voltage generation circuit generates a bandgap voltage. The current mirror branch generates a mirrored current mirrored from the bandgap voltage generation circuit. The variable resistor is electrically coupled to the current mirror branch to receive the mirrored current to generate a variable voltage. The comparator circuit compares the bandgap voltage and the variable voltage to generate a comparison result. The control circuit generates a control signal according to the comparison result to adjust the resistance of the variable resistor and outputs a signal value when the signal value forces the variable voltage to be equal to the bandgap voltage. The temperature determining circuit generates a temperature value according to the signal value.

Temperature sensing circuit

An amplifying circuit including a first gain circuit, a second gain circuit, a Miller capacitor, a positive feedback circuit and a feedforward gain circuit. The second gain circuit is configured to receive a first gain signal from the first gain circuit and generate a second gain signal. The Miller capacitor, the positive feedback circuit and the feedforward gain circuit are electrically coupled between an input terminal and an output terminal of the second gain circuit. The positive feedback circuit is configured to feedback the signal of the output terminal of the second gain circuit to the input terminal of the second gain circuit. The feedforward gain circuit is configured to amplify the first gain signal to output a third gain signal to the output terminal of the second gain circuit.

Amplifying circuit

An amplifier circuit includes a multistage amplifier, a first feedback circuit and a second feedback circuit. The multistage amplifier includes a first-staged amplifier, a last-staged amplifier and at least one middle-staged amplifier cascaded between the first-staged amplifier and the last-staged amplifier. The first feedback circuit is configured to couple a positive output end of the last-staged amplifier to a positive input end of the at least one middle-staged amplifier, or is configured to couple a negative output end of the last-staged amplifier to a negative input end of the at least one middle-staged amplifier. The second feedback circuit is configured to couple the positive output end of the last-staged amplifier to a positive input end of the last-staged amplifier, or is configured to couple the negative output end of the last-staged amplifier to a negative input end of the last-staged amplifier.

Amplifier circuit

A temperature sensing circuit includes a current source circuit, a resistor, a bandgap voltage generation circuit, a voltage-equalizing circuit and a temperature determining circuit. The current source circuit has a first current output terminal and a second current output terminal. The bandgap voltage generation circuit includes a pair of bipolar junction transistors. The voltage-equalizing circuit equalizes voltages of a first current output terminal and the second current output terminal. The temperature determining circuit includes a sampling capacitor and a calculation circuit. The sampling capacitor samples a first voltage of a first terminal of the resistor and a second voltage of a second terminal of the resistor. The calculation circuit generates a temperature value by calculating a voltage difference between the first voltage and the second voltage.

A calibration device includes a signal generator and a processor. The signal generator is configured to provide an input signal to a filter circuit, wherein the filter circuit has a real time constant and is configured to receive the input signal to output an output signal. The processor is configured to calculate a real gain according to the output signal and the input signal, compare the real gain with a target gain to obtain a comparison result and determine whether to adjust the real time constant of the filter circuit according to the comparison result. The present disclosure also provides a calibration method.

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Hsinchu, Taiwan

Chih-Chan Tu