31results about How to "Increased unity-gain bandwidth" patented technology

A low dropout linear voltage regulator with wide output current range and low pressure difference, comprises an error amplifier in the folding common source and common gate structure, a buffer circuit, a driving element, a feedback circuit, a load capacitance equivalent series resistance compensating circuit and a multistage Miller compensation circuit, wherein the buffer circuit changes the low frequency pole into a medium frequency pole and a high frequency pole; the large load capacitance of the load capacitance equivalent series resistance compensating circuit pushes the main pole to the low frequency, causing the gain crossover point to push inwards, and generating a medium frequency zero point for counteracting the medium frequency pole connected serially with the equivalent series resistance; the stride multilevel Miller compensation circuit generates a medium high frequency pole and a medium high frequency zero point slightly smaller than the medium high frequency pole for advancing the phase margin, thereby not only adding the unity gain bandwidth, but also saving considerable chip area. When the output current has a large change range, the structure provided by the invention generates wider unity gain bandwidth, provides the phase margin of greater than 85 degrees, ensures the stability of the system and advances the low pressure difference linear voltage stabilization performance.

In an imaging array having a plurality of pixel sensors arranged in a plurality of rows and columns, pixel data being read out on column lines of the array, a column line voltage clamp circuit for column lines of the array includes a master voltage clamp circuit coupled to provide a reference voltage clamp level on a reference node, and a slave voltage clamp circuit coupled to each column line in the imaging array, each slave voltage clamp circuit configured to clamp voltage on the column line to a column voltage clamp level derived from the reference voltage level.

The invention discloses an operational amplifier for a pipelined analog-to-digital converter, comprising: a first main operational amplifier and a second main operational amplifier; the first main operational amplifier includes first cascode P-type amplifiers connected in sequence The transistor pair, the second cascode P-type transistor pair, the first cascode N-type transistor pair, the first common-source N-type transistor pair, the source of the first common-source N-type transistor pair is connected to the first Tail current N-type transistor; the second main operational amplifier includes a third cascode P-type transistor pair and a second common-source N-type transistor pair connected in sequence, and the source of the second common-source N-type transistor pair A second tail current N-type transistor is connected; wherein, the drains of the first cascode P-type transistor pair are respectively connected to the drains of the third cascode P-type transistor pair through compensation capacitors. Compared with the prior art, the invention can greatly improve the gain and precision of the operational amplifier under low voltage conditions.

The present invention provides a transconductance amplifier comprising an input circuit, a gain circuit and an output circuit which are successively connected. The gain circuit comprises a MOS transistor array composed of a plurality of MOS transistors, grids of the corresponding MOS transistors between every two adjacent columns of the MOS transistor array are connected, the MOS transistors in each column of the MOS transistors are successively connected, and compensation capacitors are arranged between asymmetrical connection points of the MOS transistors in the output column of the MOS transistor array and an output terminal of the output circuit. According to the transconductance amplifier, compared with a traditional frequency compensation technology, dominant pole frequency of the transconductance amplifier can be reduced through increasing capacitance values of the compensation capacitors, right half plane zero frequency of the transconductance amplifier can also be prevented from being reduced, so that a distance between the dominant pole frequency and the right half plane zero frequency of the transconductance amplifier can be increased, the influence of frequency compensation on frequency characteristics of the transconductance amplifier can be reduced, unity-gain bandwidth of the transconductance amplifier can be improved, and the problem that the transconductance amplifier is possibly unstable can be solved.

The present invention provides a frequency-compensated transconductance amplifier, includes an input stage consisting of NMOS transistors M1 and M2, a first-stage active load consisting of PMOS transistors M3 and M4, a first-stage tail current source consisting of a constant current source Iss, a second-stage input transistor consisting of a PMOS transistor M5, a second-stage constant current source consisting of an NMOS transistor M6, a load capacitor consisting of a capacitor CL, and a frequency compensation network formed by sequentially connecting a gain stage GAIN, a compensating resistor Rc and a compensating capacitor Cc in series.

The invention discloses a low-ripple switched-capacitor common-mode feedback structure. Two sets of MOS transistors which are connected into a diode are inserted between common-mode feedback output and a fully differential operational amplifier to achieve filtering of common-mode output signals, and therefore ripples of original output common-mode feedback signals are reduced. The low-ripple switched-capacitor common-mode feedback structure aims at reducing the voltage ripples of the feedback signals of a common-mode feedback circuit in the fully differential operational amplifier, the influences of small signals caused by clock feedthrough and capacitor charging and discharging on the fully differential operational amplifier are greatly reduced, and the output precision of the fully differential operational amplifier is improved. In addition, a traditional switched-capacitor common-mode feedback circuit needs a larger sampling capacitor, but in the low-ripple switched-capacitor common-mode feedback structure, the fewer ripples are achieved by using a smaller sampling capacitor, the load capacitor size is reduced, and the unity-gain bandwidth of the fully differential operational amplifier is increased.

The invention relates to a three-progression operational amplifier based on damping factor frequency compensation and direct current offset cancellation, comprising a first amplifier, a second amplifier, a third amplifier, a damping factor control module, a first compensation capacitor and a fourth amplifier. The three-progression operational amplifier provided by the invention and based on the damping factor frequency compensation and direct current offset cancellation effectively inhibits peak effect from appearing near unity-gain bandwidth by adding a first compensation capacitor Cm1 and the damping factor control module, and a value of the first compensation capacitor Cm1 can be reduced and the unity-gain bandwidth of the amplifier is increased; meanwhile, a subthreshold feedback operational amplifier is added into a third amplifier AMP3 of the three-progression operational amplifier, so that direct current offset of the operational amplifier is effectively suppressed.