35results about How to "Improve PSRR" patented technology

An amplifier and a driver circuit therefor are presented for driving a load according to a system analog input. The amplifier comprises a passive delta-sigma modulator with a passive filter providing a first filtered signal according to a passive filter input and according to a feedback signal, a quantizer coupled with the passive filter and providing a quantized output according to the first filtered signal, and a switching system coupled with the the passive filter and the quantizer. The switching system selectively providing power to a load according to the quantized output and provides the feedback signal to the passive input, wherein a gain amplifier is provided in a feedback loop around the passive delta-sigma modulator.

Methods and systems for fully differential frequency doubling include receiving a differential input signal having a first frequency, generating a non-inverted or positive output signal having twice the frequency of the input signal, and generating an inverted or negative version of the positive output signal. The positive and negative output signals form a fully differential output. The duty ratio of the output signals substantially matches a duty ratio of the input signals. Fully differential frequency doubling can be implemented with NMOS and / or PMOS devices. The invention further provides optional circuitry for increasing an output signal level.

The present invention provides a microphone amplifier circuit, comprising a first transistor, a second transistor, a third transistor, a fourth transistor, a first reference current source and a second reference current source, wherein the gate electrode of the first transistor is used as an input of the microphone amplifier circuit, the source electrode thereof is used as an output, and the drain electrode of the first transistor is grounded through the first reference current source; the gate electrode of the second transistor is connected to the drain electrode of the first transistor, the source electrode thereof is grounded, and the drain electrode thereof is connected to a reference voltage by the second reference current source; the gate electrode of the third transistor is connected to the drain electrode of the second transistor, the source electrode thereof is connected to the source electrode of the first transistor, and the drain electrode thereof is connected to the source electrode of the fourth transistor; and the gate electrode of the fourth transistor is connected to the reference voltage, and the drain electrode thereof is connected to a power supply voltage. Compared with the related art, the microphone amplifier circuit of the present invention has the advantages of low current consumption and high PSRR.

The invention discloses a current source generator, comprising: a bandgap source core module for generating a stable reference voltage; an isolation module 1, which is connected to the bandgap source core module and is used to perform noise on the stable reference voltage isolation; a filter module, connected with the isolation module 1, for filtering the stable reference voltage after noise isolation; a reference current generator, connected with the filter module, for generating a reference current; isolation module 2, It is connected with the bandgap source core module, and is used for noise isolation of the stable reference voltage; the PTAT current generator is connected with the second isolation module, and is used for generating a current with a positive temperature coefficient. The invention overcomes the defect of high power supply voltage through the bandgap source core module containing preLDO, and achieves the purpose of low power supply and low power consumption; the isolation module and filter module are used to achieve the purpose of simultaneously having low power consumption, low noise and high PSRR .

The invention discloses a low-dropout linear voltage stabilizer. The low-dropout linear voltage stabilizer comprises an error amplifier, a regulation pipe, a sampling circuit and a miller capacitor, and further comprises a cathode-input amplifier. The cathode-input amplifier is arranged between the miller capacitor and the grid electrode of the regulation pipe. The miller capacitor is connected with the cathode-input amplifier and the drain electrode of the regulation pipe. The cathode-input amplifier buffers samples of the miller capacitor and then feeds the samples back to the output end of the error amplifier. The miller capacitor and the grid electrode of the compensating pipe are isolated through a buffer while main poles and auxiliary poles are separated, and therefore the aims of increasing stability of the circuit and improving the PSRR are achieved.

The invention relates to a high frequency amplifier, comprising a first transimpedance amplifier receiving an input current and outputting a first voltage; a second transimpedance amplifier outputting a second voltage; a third amplifier receiving the first voltage and a second voltage; and a variable current source, coupled between the input terminal of the second transimpedance amplifier and a ground terminal or a system voltage source (power supply), for outputting a variable current to change the second voltage , so that the second voltage follows the first voltage. When the input current flows into the first transimpedance amplifier, the variable current flows into the second transimpedance amplifier. When the input current flows out of the first transimpedance amplifier, the variable current flows out of the second transimpedance amplifier.