A driver system includes a non-inverting system input, an inverting system input, a non-inverting system output and an inverting system output. The driver system includes a line driver which includes a non-inverting driver input coupled to the non-inverting system input and includes an inverting driver input coupled to the inverting system input. The line driver includes an inverting driver output and a non-inverting driver output. The driver system includes a first termination resistor coupled between the non-inverting driver output and the non-inverting system output and includes a second termination resistor coupled between the inverting driver output and the inverting system output. The driver system includes a first amplifier stage coupled to the line driver and includes a second amplifier stage coupled to the line driver.

An embodiment circuit includes an operational amplifier having a first output terminal and a second output terminal. The circuit further includes a detector coupled between the first output terminal and the second output terminal of the operational amplifier. The detector is configured to detect a common-mode output voltage at the first output terminal and the second output terminal of the operational amplifier. The circuit also includes a feedback amplifier having a first input terminal coupled to the detector and a second input terminal configured to receive a reference voltage. The feedback amplifier is configured to generate a feedback signal based on the common-mode output voltage and the reference voltage and to provide the feedback signal to the operational amplifier. The circuit additionally includes an impedance element having a first terminal coupled to the first input terminal of the feedback amplifier and a second terminal coupled to a supply voltage.

The present invention is directed to electrical circuits and techniques thereof. More specifically, an embodiment of the present invention provides a line driver with transistors directly coupled to the ground, and a bias voltage is coupled common mode resistors of the line driver. There are other embodiments as well.

A differential signal conditioner circuit with common mode voltage (CMV) compensation is provided. The circuit includes a signal multiplexer that receives a input signal that includes a high and low signal and a reference CMV signal, a differential amplifier coupled to the signal multiplexer that receives the reference CMV signal and outputs a CMV error value during a first cycle, and receives the input signal and outputs an amplified difference signal during a second cycle. The circuit also includes a CMV measurement circuit that receives the reference CMV signal and outputs a confirmation value during the first cycle, and receives the input signal and outputs a CMV compensation value during the second cycle, and a processing element that receives the CMV error value, the amplified difference signal, the CMV compensation value, and a differential amplifier gain value and generates a CMV compensated output based on the received signals and values.

A differential signal conditioner circuit with common mode voltage (CMV) compensation is provided. The circuit includes a signal multiplexer that receives a input signal that includes a high and low signal and a reference CMV signal, a differential amplifier coupled to the signal multiplexer that receives the reference CMV signal and outputs a CMV error value during a first cycle, and receives the input signal and outputs an amplified difference signal during a second cycle. The circuit also includes a CMV measurement circuit that receives the reference CMV signal and outputs a confirmation value during the first cycle, and receives the input signal and outputs a CMV compensation value during the second cycle, and a processing element that receives the CMV error value, the amplified difference signal, the CMV compensation value, and a differential amplifier gain value and generates a CMV compensated output based on the received signals and values.

Systems and methods for providing thermal compensation for amplifiers are described. In some embodiments, an electronic circuit may include a main amplifier and a thermal compensation circuit coupled to the main amplifier, the thermal compensation circuit configured to adjust a gain of the main amplifier at a first range of frequencies relative to the gain of the main amplifier at a second range of frequencies. For example, the thermal compensation circuit may be configured to reduce a self-heating effect within the main amplifier when the main amplifier is in operation, such that the first range of frequencies is lower than the second range of frequencies.

A first transistor has a first terminal and a second terminal. A second transistor has a third terminal, a fourth terminal and a fifth terminal electrically connected to the second terminal of the first transistor during amplification performed by the first transistor. A first bias circuit is electrically connected to the first terminal of the first transistor and supplies a first bias to the first terminal so that a magnitude of the first bias is increased with a rise in circuit temperature. A second bias circuit is electrically connected to the third terminal of the second transistor and supplies a second bias to the third terminal so that the magnitude of the second bias is constantly maintained with respect to changes in the circuit temperature.

The present invention provides a single-end-to-differential microphone circuit and an electronic equipment, including: an amplifier, a microphone connected to the positive input end of the amplifier, a coupling capacitor C.sub.AC connected to the negative input end of the amplifier, a first feedback capacitor C.sub.FB1 connected to the negative output end of the amplifier, a first feedback resistor R.sub.FB1 connected in parallel with the first feedback capacitor C.sub.FB1, a second feedback capacitor connected to the positive output end of the amplifier C.sub.FB2, and a second feedback resistor R.sub.FB2 connected in parallel with the second feedback capacitor C.sub.FB1. The circuit of the present invention can adopt a microphone structure with smaller capacity, and at the same time has a better system signal to noise ratio.

The present invention is directed to electrical circuits and techniques thereof. More specifically, embodiments of the present invention provide a differential amplifier that has a differential amplifier section, a current source, and a feedback section. The differential amplifier section comprises NMOS transistors that receives two voltage inputs and generate a differential output. The current source provides a long tail for the differential amplifier section. The feedback section generates a feedback voltage based on a reference bias voltage. The feedback voltage is used by an amplifier to control the current source and to keep the biasing and gain of the differential amplifier substantially constant. There are other embodiments as well.

Systems and methods disclosed herein provide for enhancing the low frequency (DC) gain of an operational amplifier with multiple correlated level shifting capacitors. In an embodiment, the operational amplifier is level shifted with a first correlated level shifting capacitor in a first phase and, then, is level shifted again with at least a second correlated level shifting capacitor in at least a second, non-overlapping, consecutive phase. In an embodiment, the multiple correlated level capacitors are controlled by a switching circuit network.