Abstract: Amplifiers with power-on trim and methods using an amplifier system having an amplifier system input and an amplifier system output, an amplifier, a comparator, a successive approximation register having an input coupled to an output of the comparator, a first switch for switching an input of the amplifier from the amplifier system input to shorting the amplifier input, a second switch for switching an output of the amplifier from the amplifier system output to an input of the comparator, an output of the successive approximation register being coupled to an N bit digital to analog (D/A) converter, the D/A converter being a non-binary converter using a radix of less than 2 for at least the most significant bits, and an output of the D/A converter being coupled to the amplifier to control the input offset of the amplifier. Novel embodiments for the amplifier, comparator and D/A converter are disclosed.

Abstract: Low-noise, low-power, low drift offset correction in operational and instrumentation amplifiers and amplifiers using the same are disclosed. The amplifiers disclosed use different combinations of chopping and auto-zero techniques. Also disclosed are amplifiers using on-off switches to affect the chopping and auto-zeroing, with unique circuits for driving the switches on the differential input to provide boot-strapped switch controls. Other features are disclosed.

Abstract: The present invention comprises class AB amplifier systems exhibiting low quiescent power, low-voltage operation, high gain, high bandwidth, low noise and low offset, and requiring a small die area. The amplifier systems use a differential first stage and a second stage of two pair of nested current mirrors interconnected in a particular way. Using a low quiescent current, the present invention reduces power consumption almost to a theoretical minimum. Also the circuit will operate at an input of only 1.8V with a threshold voltage of 1V. Various embodiments are disclosed.

Abstract: Amplifiers with power-on trim and methods using an amplifier system having an amplifier system input and an amplifier system output, an amplifier, a comparator, a successive approximation register having an input coupled to an output of the comparator, a first switch for switching an input of the amplifier from the amplifier system input to shorting the amplifier input, a second switch for switching an output of the amplifier from the amplifier system output to an input of the comparator, an output of the successive approximation register being coupled to an N bit digital to analog (D/A) converter, the D/A converter being a non-binary converter using a radix of less than 2 for at least the most significant bits, and an output of the D/A converter being coupled to the amplifier to control the input offset of the amplifier. Novel embodiments for the amplifier, comparator and D/A converter are disclosed.

Abstract: Low-noise, low-power, low drift offset correction in operational and instrumentation amplifiers and amplifiers using the same are disclosed. The amplifiers disclosed use different combinations of chopping and auto-zero techniques. Also disclosed are amplifiers using on-off switches to affect the chopping and auto-zeroing, with unique circuits for driving the switches on the differential input to provide boot-strapped switch controls. Other features are disclosed.

Abstract: The present invention comprises class AB amplifier systems exhibiting low quiescent power, low-voltage operation, high gain, high bandwidth, low noise and low offset, and requiring a small die area. The amplifier systems use a differential first stage and a second stage of two pair of nested current mirrors interconnected in a particular way. Using a low quiescent current, the present invention reduces power consumption almost to a theoretical minimum. Also the circuit will operate at an input of only 1.8V with a threshold voltage of 1V. Various embodiments are disclosed.

Abstract: Amplifiers with power-on trim and methods using an amplifier system having an amplifier system input and an amplifier system output, an amplifier, a comparator, a successive approximation register having an input coupled to an output of the comparator, a first switch for switching an input of the amplifier from the amplifier system input to shorting the amplifier input, a second switch for switching an output of the amplifier from the amplifier system output to an input of the comparator, an output of the successive approximation register being coupled to an N bit digital to analog (D/A) converter, the D/A converter being a non-binary converter using a radix of less than 2 for at least the most significant bits, and an output of the D/A converter being coupled to the amplifier to control the input offset of the amplifier. Novel embodiments for the amplifier, comparator and D/A converter are disclosed.

Abstract: Amplifiers with power-on trim and methods using an amplifier system having an amplifier system input and an amplifier system output, an amplifier, a comparator, a successive approximation register having an input coupled to an output of the comparator, a first switch for switching an input of the amplifier from the amplifier system input to shorting the amplifier input, a second switch for switching an output of the amplifier from the amplifier system output to an input of the comparator, an output of the successive approximation register being coupled to an N bit digital to analog (D/A) converter, the D/A converter being a non-binary converter using a radix of less than 2 for at least the most significant bits, and an output of the D/A converter being coupled to the amplifier to control the input offset of the amplifier. Novel embodiments for the amplifier, comparator and D/A converter are disclosed.

Abstract: A turn-around stage is provided that accepts the full current swing from an input stage while maintaining a low quiescent current. The circuitry provides Class AB operation with quiescent currents that are significantly less than the maximum signal current so that overall power consumption is significantly reduced. Also, the amount of noise and offset contributions of the circuit are reduced by reducing the transconductances associated with transistors included in the turn-around stage.

Abstract: A turn-around stage is provided that accepts the full current swing from an input stage while maintaining a low quiescent current. The circuitry provides Class AB operation with quiescent currents that are significantly less than the maximum signal current so that overall power consumption is significantly reduced. Also, the amount of noise and offset contributions of the circuit are reduced by reducing the transconductances associated with transistors included in the turn-around stage.

Abstract: A self-biased electret microphone amplifier with phantom powering which avoids the need for JFETs and depletion mode devices, both of which are not standard devices when using BiCMOS fabrication processes. Feedback is included to provide enhanced gain, dynamic range, linearity and temperature stability, without requiring filtering, large resistances or external components. A self-biased, phantom powered, differential MOSFET amplifier receives and pre-amplifies the microphone signal. Further amplification and feedback is provided by a differential amplifier and bipolar output amplifier which operates as a common emitter amplifier for the amplified microphone output signal and as an emitter follower amplifier for the feedback signal.

Abstract: A low voltage amplifier with gain boosting and a reduced power supply voltage requirement. A cascode amplifier circuit, biased with the power supply voltage, amplifies a pair of related, differential input signals based upon a pair of gain boost control signals and in accordance therewith provides a pair of gain boosted signals which correspond to the input signals. A gain boost control circuit, also biased with the power supply voltage, uses the differential input signals to generate the gain boost control signals. A class AB amplifier circuit, also biased with the power supply voltage, amplifies the gain boosted signals and in accordance therewith provides a class AB output signal which corresponds to the original input signals. The cascode amplifier circuit, gain boost control circuit and class AB amplifier circuit together operate with a minimum power supply voltage which equals a sum of one active transistor input bias potential and two active transistor output bias potentials(V.sub.DD(min) -V.sub.SS =V.