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.

An amplifier includes a dynamic bias circuit and an amplification circuit coupled to the dynamic bias circuit. The dynamic bias circuit includes a plurality of transistors coupled to a plurality of resistors. The dynamic bias circuit is configured to generate a bias current with a magnitude that increases in response to the dynamic bias circuit receiving a falling edge of an input signal and decreases in response to the dynamic bias circuit receiving a rising edge of the input signal. The amplification circuit is configured to receive the bias current and amplify the input signal based on the bias current to generate an output signal that has a higher slew rate for a falling signal than for a rising signal.

A differential amplifier generates an output voltage waveform exhibiting a slew rate over a rise time. The amplifier is powered from a dc voltage input and includes a set of differential pairs having a bias current flowing therethrough and a Miller compensation capacitance. A comparator functions to compare a voltage at the dc voltage input against a reference voltage in order to detect when the voltage drops below the reference voltage. A gain stage controls the gain of the differential amplifier and a bias current control circuit controls the bias current of the differential amplifier. In response to the detection by the comparator of the voltage dropping below the reference voltage, the gain stage and the bias current control circuit decrease the gain of the amplifier and jointly decrease the bias current in order to maintain a value of the rise time.

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.

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.

In a folded cascode operational amplifier circuit, a source is connected to a back gate in each of third and fourth transistors that are cascode-connected to first and second transistors, which are an electric current source that returns an electric current signal output by a differential pair of an input stage. In the third and fourth transistors, an active parasitic element exists due to its device structure. When a falling edge signal of a rectangular wave is input, and electric current is supplied to the source of the third transistor to increase its electric potential, electric current flows into the drain from the back gate via the active parasitic element in an on state, in order to rapidly charge a capacitor. Thereby, a fifth transistor turns on within a shorter time, in order to improve an internal slew rate.

Disclosed is an amplifier having a high slew rate without increasing power consumption. The amplifier includes an input unit, a conversion unit, an amplification unit, a frequency compensation circuit, and a slew rate improvement circuit. Alternatively, the amplifier includes an input unit, a conversion unit, an amplification unit, a frequency compensation circuit, a first slew rate improvement circuit, and a second slew rate improvement circuit.

A regulator includes a first operational amplifier configured to receive a reference voltage and a feedback voltage and to output a node voltage based on a difference of the feedback voltage and the reference voltage; a first switch unit configured to receive the node voltage and to supply a recover current based on the node voltage; an output unit configured to output an output voltage and the feedback voltage according to a supply of the recover current; a comparison unit configured to receive the reference voltage and a feedback voltage and to sense a voltage drop of the output voltage; and a second switch unit configured to discharge the first switch unit according to the difference of the reference voltage and the feedback voltage.

Provided herein are apparatus and methods for compensating an operational amplifier (op-amp). In certain configurations, a compensation network is electrically connected between an output node of the op-amp and an input differential pair coupled source/emitter tail-current node. The compensation network can include a capacitor having a relatively low value of capacitance. In this manner, op-amp bandwidth is improved while power consumption is reduced to meet a green standard.

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.