A circuit that receives AC power for rectification and analog DC control signals for processing. Two voltages may be noted. A first voltage may be between a supply ground and an internal device ground of a rectifier. A second voltage may be between a terminal of an input control signal source and the internal device ground. To get a control signal value, one may need a differential of those two voltages that can be accomplished with an operational amplifier configured as differential amplifier. A range of an input control signal may be from zero to a particular magnitude of voltage. A reasonably priced operational amplifier might not have an ability provide an output to zero. However, a linearized transistor output stage, having an output that can go to zero, may be connected to an output of the operational amplifier so as to effectively provide an output that goes to zero.

In a general aspect, a circuit can include an amplifier circuit including a first amplifier, a first feedback path, and a second feedback path. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier, The circuit can also include a loop circuit including a second amplifier, The loop circuit can be configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and into the negative input of the first amplifier.

A differential amplifier provides improved signal swing and reduced common-mode output noise. The differential amplifier circuit includes a driver circuit with a first output for driving a first output of the differential amplifier and with a second output for driving a second output of the differential amplifier. The driver circuit has inputs for receiving a differential (complementary) pair of input signals at least one common-mode reference input for receiving a common-mode reference signal. The differential amplifier also includes a signal maxima detector having inputs for receiving the differential input signals that detects a maximum value between the individual signals, including any input common-mode voltage. The differential amplifier also includes a common-mode reference circuit that provides the common-mode reference signal and an input coupled to an output of the signal maxima detector, so that a common-mode voltage of the outputs is independent of power supply voltages provided to the driver circuit.

In at least one embodiment, a fully differential amplifier is provided. A first amplifying circuit receives a first input voltage signal and provides a first output voltage signal. A second amplifying circuit to receive a second voltage signal and to provide a second output voltage signal. A summing circuit to provide a common mode component of the first input voltage signal and the second input voltage signal. A compensation circuit to amplify the common mode component of the first input voltage signal and the second input voltage signal and output an injection signal. A common gain setting network including a plurality of resistors to receive the injection signal and to interface with the first amplifying circuit, the second amplifying circuit, and the compensation circuit to prevent the common mode component from being present in the first output voltage signal and the second output voltage signal.

In a general aspect, a circuit can include an amplifier circuit including a first amplifier, a first feedback path, and a second feedback path. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier. The circuit can also include a loop circuit including a second amplifier. The loop circuit can be configured to provide a local feedback loop for the first amplifier and configured to control current flow into the positive input of the first amplifier and into the negative input of the first amplifier.

A successive approximation type AD converter includes an in-phase voltage detection and supply circuit that supplies an in-phase voltage obtained by impedance voltage division of a first input analog signal and a second input analog signal to a first capacitance DA converter and a second capacitance DA converter. The first capacitance DA converter samples the first input analog signal with reference to the in-phase voltage, and the second capacitance DA converter samples the second input analog signal with reference to the in-phase voltage. After the sampling period ends, a comparator compares the output of the first capacitance DA converter and the output of the second capacitance DA converter, output voltages of the first capacitance DA converter and the second capacitance DA converter are changed by the control signal of a successive approximation logic unit on the basis of a comparison result, and comparison processing is repeated.

A successive approximation type AD converter includes an in-phase voltage detection and supply circuit that supplies an in-phase voltage obtained by impedance voltage division of a first input analog signal and a second input analog signal to a first capacitance DA converter and a second capacitance DA converter. The first capacitance DA converter samples the first input analog signal with reference to the in-phase voltage, and the second capacitance DA converter samples the second input analog signal with reference to the in-phase voltage. After the sampling period ends, a comparator compares the output of the first capacitance DA converter and the output of the second capacitance DA converter, output voltages of the first capacitance DA converter and the second capacitance DA converter are changed by the control signal of a successive approximation logic unit on the basis of a comparison result, and comparison processing is repeated.

In a general aspect, a system can include a fully differential amplifier circuit that includes a first amplifier, and first and second feedback paths. The first feedback path can provide a feedback path from a positive output of the first amplifier to a negative input of the first amplifier. The second feedback path can provide a feedback path from a negative output of the first amplifier to a positive input of the first amplifier. The system can include a chopper clock circuit configured to output a variable duty cycle chopper clock signal. The system can include a common mode loop circuit including a second amplifier and chopper switches. The common mode loop circuit can be configured as a local feedback loop for the first amplifier. The chopper switches can be configured to receive the chopper clock signal and control current flow into the positive and negative inputs.

Amplifying circuitry configured such that when a detection circuit detects an abnormal state in which the level of signals input to a main amplifying circuit exceeds a normal range, a control circuit sets the state of integration of signals in the integration circuit to a default state. When the detection circuit detects the abnormal state and then detects that an operating state returns to a normal state in which the level of signals input to the main amplifying circuit is included in the normal range, the control circuit cancels the setting of the default state in the integration circuit.

A signal receiver includes a first transistor, a second transistor, a load circuit, an amplifying circuit and a load circuit. The first transistor has a first end receiving a power voltage, and a control end receive a first input signal. The second transistor has a first end receiving the power voltage, and a control end receiving a second input signal, wherein the first input signal and the second input signal are differential signals and transit between a first voltage and a reference ground voltage, the first voltage is larger than the power voltage. The load circuit is coupled to the first transistor and the second transistor. The amplifying circuit generates an output signal according a first signal on the second end of the first transistor and a second signal on the second end of the second transistor.