Disclosed herein are differential amplifiers for improved slew performance. In some embodiments, a differential amplifier may receive positive and negative input signals at first and second transistor branches, respectively; provide a dynamic bias current to the first and second transistor branches, responsive to the positive and negative input signals; and provide positive and negative output signals at the second and first transistor branches, respectively.

An amplification circuit according to the present embodiment includes a first amplifier, a second amplifier, a capacitor, and an adjustment circuit. The first amplifier amplifies an input signal and outputs a first amplified signal. The second amplifier amplifies the first amplified signal input from the first amplifier through a connection line and outputs a second amplified signal. The capacitor is arranged between the connection line and an output line through which the second amplifier outputs the second amplified signal. The adjustment circuit changes a charge/discharge state of the capacitor according to a value of the input signal.

A slew rate acceleration circuit in a buffer circuit, is configured at least to detect a current flowing through a load stage of the buffer circuit, compare a value of the detected current with a reference value, and supply an adjusting driving voltage to an output stage of the buffer circuit based on results of the comparison for increasing a slew rate of the buffer circuit.

In one embodiment, an amplifier is configured to include a pre-drive circuit that forms an estimated value of an output signal of the amplifier and forces the output to the estimated value before the amplifier forms the output signal.

An operational amplifier circuit includes: a first differential amplifier section containing a P-type differential pair of P-type transistors; a second differential amplifier section containing an N-type differential pair of N-type transistors; an intermediate stage connected with outputs of the first and second differential amplifier sections and containing a first current mirror circuit of P-type transistors, and a second current mirror circuit of N-type transistors; and an output stage configured to amplify an output of the intermediate stage in power. The first differential amplifier section includes a first current source and a first capacitance between sources of the P-type transistors of the P-type differential pair and a positive side power supply voltage. The second differential amplifier section includes a second current source and a second capacitance between sources of the N-type transistors of the N-type differential pair and a negative side power supply voltage.

A buffer amplifier circuit includes a buffer amplifier including a first differential amplifier having a first active load and a second differential amplifier having a second active load and a feedback circuit configured to feed an output signal of an output terminal of the buffer amplifier back to one of the first and second active loads using differential switch signals and an input signal of the buffer amplifier to enhance a slew rate of the output signal.

A buffer circuit is provided. The buffer circuit includes an operational amplifier and a slew-rate compensating circuit. The operational amplifier amplifies an input voltage signal and generates an output voltage signal. The slew-rate compensating circuit generates a compensation current based on a voltage difference between the input voltage signal and the output voltage signal, and provides the compensation current to a load stage of the operational amplifier.

An example apparatus includes: a first transistor having a first terminal and a control terminal; a second transistor having a first terminal and a control terminal, the first terminal of the second transistor coupled to the first terminal of the first transistor; a third transistor having a first terminal and a control terminal; a fourth transistor having a first terminal and a control terminal, the first terminal of the fourth transistor coupled to the first terminal of the third transistor; feedback circuitry coupled to the first transistor, the second transistor, the third transistor and the fourth transistor; current source circuitry having a first terminal and a second terminal, the first terminal of the current source circuitry coupled to the feedback circuitry; slew assist circuitry coupled to the first transistor, the second transistor, the third transistor and the fourth transistor, the feedback circuitry and the current source circuitry.

An exemplary embodiment of the present disclosure relates to a rail-to-rail class-AB buffer amplifier using compact adaptive biasing, and the rail-to-rail class-AB buffer amplifier using compact adaptive biasing includes an input stage generating a differential current pair based on a voltage difference between a first input signal and a second input signal, an amplification stage outputting a driving signal based on the differential current pair, an output stage connected to the amplification stage and outputting an output signal, an auxiliary current source switch which is on/off based on the driving signal of the amplification stage, and a current mirroring unit generating bias current and outputting the generated bias current to the input stage when the auxiliary current source switch is on.

A high-voltage chopper-stabilized amplifier can include two paths to compensate for non-ideal electrical parameters. A first path, leading to a primary input of the amplifier, may include a first mux interface circuit to limit voltages at the primary input of the amplifier. A second path, leading to an auxiliary input of the amplifier, may include a chopper amplifier circuit. Despite the first mux interface circuit, a slew condition on the first path may excite a current in the second path that can negatively affect the signal source. Accordingly, the disclosed amplifier further includes a second mux interface circuit that can decouple the second path while a slew condition. The second mux interface circuit is driven by a window floating comparator, which is supplied according to the voltages on primary input. A settling enhancer circuit keeps, during slew condition, certain nodes on the second path at a reference voltage.