35results about How to "Improve PSRR" patented technology

An amplifier having an active and passive gain stage connect to a load for driving a load according to a system analog input. A first embodiment of the amplifier in accordance with the present invention includes a logic network connected between a comparator network and a switching system, wherein the comparator network connects to the passive gain stage. Specifically, the active gain stage may include an active filter connected to receive an analog or digital input and provide a difference between the analog or digital input and the feedback signal relative to the gain factor of a gain unit connected to the active filter. The passive gain stage includes a passive filter. The logic network generates at least one switching signal which controls the switching system that includes at least one switching device to selectively provide power to the load. An output signal from the switching system provides output for the amplifier and is fed back to the active gain stage. In another embodiment, the output is a two-level signal and the passive and active filters are second order low pass filters, where the gain factor is about 25 or more. In yet another embodiment, the gain factor is approximately 250. Moreover, the amplifier may include a digital delta-sigma modulator connected to supply a two level input.

An all-digital class-D audio amplifier and method of digitizing an analog signal comprises a pulse-width modulation (PWM) wave generator for generating a PWM wave; an interpolator for receiving an input audio signal, up-sample the input audio signal; and down-sample the input audio signal to a PWM wave switching frequency; an audio speaker for broadcasting an amplified version of the input audio signal; a pair of MOSFETs driven by the PWM wave and the input supply voltage, wherein the pair of MOSFETs transmit the amplified version of the input audio signal to the audio speaker; a natural-sampling and pre-distortion circuit adapted to (i) generate a pre-distorted natural-sampling frequency point for the PWM wave switching frequency, and (ii) account for digitized power supply ripples for an input supply voltage used to drive the audio speaker; and an analog-to-digital converter (ADC) adapted to digitize the power supply ripples or distortion.

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-precision output voltage-adjustable reference voltage generating circuit which comprises an output-adjustable current summation type bandgap reference voltage generating circuit, an output-adjustable current summation type difference reference voltage generating circuit and a reference voltage buffer driving circuit. The output-adjustable current summation type bandgap reference voltage generating circuit generates a bandgap reference voltage Vref for output; through the output-adjustable current summation type difference reference voltage generating circuit, difference reference voltages VTP and VTN are generated for output; and through the reference voltage buffer driving circuit, reference voltages Vrefp and Vrefn are output. Through current summation and a floating current source negative feedback control technology, the output voltage-adjustable fully differential reference voltage buffer driving circuit is designed. The buffer driving circuit is further of a structure with a source electrode push-pull output and duplicate circuit, a smaller output impedance is obtained while the power supply rejection ratio (PSRR) of the reference voltage is further improved, and the high-precision output voltage-adjustable reference voltage generating circuit has better driving capability.

The invention discloses a startup circuit and a power supply system integrated with the same. Low-voltage power supply is produced by the startup circuit to be supplied to a reference voltage source in the system when the system is powered up, thereby avoiding use of high-voltage devices by the reference voltage source. After the system works normally, the startup circuit can be turned off completely, and no additional power consumption is needed. After the power supply system integrated with the startup circuit is applied, the reference voltage source in a chip can always maintain low voltage, and only one high-accuracy low-voltage reference source needs to be constructed in the chip. Therefore, due to high-voltage application of the power supply system, the number of the applied high-voltage devices can be reduced, the area of the chip can be reduced, and the design cost can be decreased.

The invention provides a low dropout regulator (LDO). The LDO comprises a power supply rejection ratio (PSRR) improving circuit and a low-voltage difference stabilizing circuit; and when the input voltage has a high-frequency small signal, the PSRR improving circuit amplifies the high-frequency small signal and transmits to an output gaining node of the low-voltage difference stabilizing circuit so as to increase the gain of the low-voltage difference stabilizing circuit. The invention also provides a PSRR improving method of the LDO. Through the scheme provided by the invention, under the condition that the zero / pole point of the low-voltage difference stabilizing circuit is not influenced, the PSRR of the LDO when the input voltage has the high-frequency small signal is improved, and the PSRR of the LDO is more obviously improved particularly when the frequency of the small signal is higher than 100 KHz.

A current source generator comprises: a bandgap source core module (201) configured for generating a stable reference voltage; a separating module 1 (202), connected to the bandgap source core module (201) and configured for performing noise separation on the stable reference voltage; a filter (203), connected to the separating module 1 (202) and configured for filtering the stable reference voltage on which the noise separation has been performed; a reference current generator (204), connected to the filter (203) and configured for generating a reference current; a separating module 2 (205) connected to the bandgap source core module (201) and configured for performing noise separation on the stable reference voltage; and a PTAT current generator (206) connected to the separating module 2 (205) and configured for generating a current with a positive temperature coefficient.

The invention discloses a reference voltage generating circuit and belongs to the technical field of integrated circuits. The reference voltage generating circuit comprises a presetting circuit converting input voltage to presetting voltage and a core circuit generating reference voltage under the action of the presetting voltage. The presetting circuit comprises a first depletion mode N-channel metal oxide semiconductor transistor and a second depletion mode N-channel metal oxide semiconductor transistor, and the core circuit comprises a third depletion mode N-channel metal oxide semiconductor transistor, a fourth depletion mode N-channel metal oxide semiconductor transistor, an enhanced N-channel metal oxide semiconductor transistor and a first resistor. The circuit is simplified, the layout area is reduced, output of the reference voltage with an arbitrary value is realized, and the reference voltage generating circuit has the advantages of low power consumption, low noise, low temperature coefficient and high PSRR (power supply rejection ratio).

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 invention relates to the technique of integrated circuits, in particular to a current reference circuit. The current reference circuit is characterized by comprising a first current reference unit, a second current reference unit and a maximum current selecting circuit, wherein the output end of the first current reference unit is connected with the first input end of the maximum current selecting circuit, the output end of the second current reference unit is connected with the second input end of the maximum current selecting circuit, and the output end of the maximum current selecting circuit is the output end of the current reference circuit. The current reference circuit has the advantages that by adopting a cascode current mirror, currents are copied more accurately, collector electrode voltage of an audion Q1 and collector electrode voltage of an audion Q2 are accurate and equal, the PSRR is improved, the current in the first current reference unit and the current in the second current reference unit are selected by adopting the maximum current selecting circuit, and therefore the temperature coefficient of the output currents is better. The current reference circuit is particularly suitable for current reference circuits.

The invention relates to a power supply equipment, a processing chip for a digital microphone and the digital microphone. The power supply equipment contains at least two low dropout linear regulators which are connected in series. The processing chip for the digital microphone contains a processing module and a power supply module, wherein the power supply module contains at least two low dropout linear regulators which are connected in series. The digital microphone contains a microphone and the processing chip, wherein the processing chip contains the processing module and the power supply module which contains at least two serial low dropout linear regulators. The invention can provide the power supply equipment with higher power supply rejection ratio (PSRR).

The invention discloses a high-bandwidth high-PSRR low-pressure-drop linear voltage regulator. The linear voltage regulator comprises a voltage input end Vin, a reference voltage end Vref, an error amplifier EA and a power tube MP. The linear voltage regulator further comprises a feedforward circuit and an adder circuit. The feed forward circuit is connected between the voltage input end Vin and the grid electrode G of the power tube MP through the adder circuit, and the power tube MP is a PMOS power tube MP. The positive phase end of the error amplifier EA is connected with a feedback resistor. The feedback resistor is connected with a zero generation capacitor CZ in parallel. Due to the high-bandwidth high-PSRR low-pressure-drop linear voltage regulator, the voltage of the grid electrode G and the voltage of the source electrode S of the PMOS power tube MP keep unchanged, and PSRR performance is improved; besides, a second pole in the system can be eliminated by a zero generated by regulating a zero generation capacitor CZ, and therefore the stability of the system is improved.

The invention belongs to the technical field of integrated circuit and relates to a reference voltage source with high power supply rejection ratio (PSRR). The reference voltage source is characterized in that a new train of thought is put forward to improve the PSRR of different frequencies, the PSRR is improved by introducing a self-biased cascade structure as the load to shield power supply change effect when in the medium and low frequency, and the purpose of improving the PSRR is achieved by introducing capacitance filtering effect in the high frequency. The reference voltage source has the advantages that the full-band PSRR is improved, reference voltage output through the voltage reference circuit is ensured to be precise, and stability of the output reference voltage of the voltage reference circuit is improved.

The invention belongs to the field of analogue integrated circuits, and specifically relates to an I-V circuit of an infrared receiving module. The PSRR (power supply rejection ratio) of the circuit can be effectively reduced at the front end of the circuit, and the performance of the circuit is improved. The I-V circuit comprises an operational amplifier, the inverted input end of the operational amplifier is connected with the output end of the operational amplifier, the output end of the operational amplifier is connected with an adjustable resistor R1 and a photodiode which are connected in sequence, and two ends of the adjustable resistor R1 are voltage signal output ends respectively. The I-V circuit also comprises an MOS tube PM0 and an MOS tube PM1, the source end of the MOS tube PM0 and the source end of the MOS tube PM1 are connected and then are connected to one end of a current source, the bulk end of the MOS tube PM0 and the bulk end of the MOS tube PM1 are connected and then are connected to one end of a resistor R2, the grid end of the MOS tube PM0 and the grid end of the MOS tube PM1 are connected and then are grounded, the other end of the current source and the other end of the resistor are both connected to a power supply VDD respectively, the drain end of the MOS tube PM1 is grounded, the drain end of the MOS tube PM0 is connected to the normal-phase input end of the operational amplifier and one end of a capacitor C0, and the other end of the capacitor C0 is grounded.

A voltage regulator circuit includes a power supply terminal and a ground terminal, and a differential amplifier coupled between the power supply terminal and the ground terminal. The voltage regulator circuit also includes an output transistor, which includes a gate node coupled to an output node of the differential amplifier to receive a gate voltage and to provide a regulated output voltage at an output node of the output transistor. The differential amplifier is configured to provide the gate voltage based on a differential between a reference voltage and the regulated output voltage. The voltage regulator also includes a compensation capacitance coupled between a virtual ground node in the differential amplifier and either the power supply terminal or the ground terminal and a virtual ground node in the differential amplifier.

The invention provides an operational amplifier circuit. The operational amplifier circuit comprises a recycling folded cascode amplifier, wherein the recycling folded cascade amplifier comprises twofolded tubes, cascode current mirrors and a load capacitor, the grids of the cascode current mirrors are correspondingly connected, each branch of the cascode current mirrors and each of the two folded tubes are respectively in series connection with a first node and a second node, one end of the load capacitor is connected with the first node, and the other end is grounded. The operational amplifier circuit further comprises a dynamic acceleration circuit, which is suitable for helping the output voltage of the operational amplifier circuit accelerate to follow the input voltage when an inputvoltage of the recycling folded cascode amplifier jumps from the low level to the high level or from the high level to the low level. According to the operational amplifier circuit provided by the invention, due to the additionally arranged dynamic acceleration circuit, the actuating speed of the operational amplifier circuit is largely improved when the static power consumption is not increased.

A high frequency amplifier comprising a first trans-impedance amplifier, a second trans-impedance amplifier, a third amplifier, and a variant current source is provided. The first trans-impedance amplifier receives an input current and outputs a first output voltage accordingly. The second trans-impedance outputs a second voltage. The third amplifier receives the first and the second voltage. The variant current source is connected between the input terminal of the second trans-impedance and a ground terminal or a power supply source. The variant current source delivers a variant current to change the second voltage such that the second voltage may follow the first voltage. The input current flows into the first trans-impedance amplifier, while the variant current flows into the second trans-impedance amplifier. The input current flows out the first trans-impedance amplifier, while the variant current flows out the second trans-impedance amplifier.

The invention relates to a high-precision output voltage-adjustable reference voltage generating circuit which comprises an output-adjustable current summation type bandgap reference voltage generating circuit, an output-adjustable current summation type difference reference voltage generating circuit and a reference voltage buffer driving circuit. The output-adjustable current summation type bandgap reference voltage generating circuit generates a bandgap reference voltage Vref for output; through the output-adjustable current summation type difference reference voltage generating circuit, difference reference voltages VTP and VTN are generated for output; and through the reference voltage buffer driving circuit, reference voltages Vrefp and Vrefn are output. Through current summation and a floating current source negative feedback control technology, the output voltage-adjustable fully differential reference voltage buffer driving circuit is designed. The buffer driving circuit is further of a structure with a source electrode push-pull output and duplicate circuit, a smaller output impedance is obtained while the power supply rejection ratio (PSRR) of the reference voltage is further improved, and the high-precision output voltage-adjustable reference voltage generating circuit has better driving capability.

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 .

An operational amplifier circuit, comprising: a loop folded cascode amplifier, the loop folded cascode amplifier includes two folded tubes, a cascode current mirror and a load capacitor, the cascode current mirror The gates are connected correspondingly, each branch of the cascode current mirror and each of the two folded tubes are respectively connected in series with the first node and the second node, and one end of the load capacitor is connected to the first node, The other end is grounded; it also includes: a dynamic acceleration circuit, which is suitable for making the The output voltage of the operational amplifier circuit accelerates to follow the input voltage. In the operational amplifier circuit provided by the present invention, by adding the dynamic acceleration circuit, the driving speed of the operational amplifier circuit is greatly improved without increasing the static power consumption.

The invention discloses a startup circuit and a power supply system integrated with the same. Low-voltage power supply is produced by the startup circuit to be supplied to a reference voltage source in the system when the system is powered up, thereby avoiding use of high-voltage devices by the reference voltage source. After the system works normally, the startup circuit can be turned off completely, and no additional power consumption is needed. After the power supply system integrated with the startup circuit is applied, the reference voltage source in a chip can always maintain low voltage, and only one high-accuracy low-voltage reference source needs to be constructed in the chip. Therefore, due to high-voltage application of the power supply system, the number of the applied high-voltage devices can be reduced, the area of the chip can be reduced, and the design cost can be decreased.

The technical scheme of the invention provides a power amplifier which comprises a bandgap reference circuit and a first amplifier, wherein the bandgap reference circuit is suitable for generating a first common-mode voltage and is connected with the common-mode voltage input terminal of the first amplifier so as to provide the common-mode voltage to the first amplifier; and the bandgap reference circuit is also suitable for generating a first reference current and is connected with the reference current input terminal of the first amplifier so as to offer reference current to the first amplifier. According to the technical scheme adopted by the invention, the bandgap reference circuit offers not only the reference current, but also the common mode voltage to the first amplifier, and as a result, the PSRR (Power Supply Rejection Ratio) of the whole power amplifier is improved. Moreover, the power amplifier has the advantages of simple structure and low alteration cost.

The invention discloses a low-dropout linear voltage stabilizer, and belongs to the technical field of integrated circuits. The low-dropout linear voltage stabilizer comprises an output MOS tube, a voltage sampling circuit connected to the current outflow end of the output MOS tube in series, a voltage comparison circuit comparing a sampled signal with a standard voltage value to obtain an error signal, and a Buffer drive circuit driving the output MOS tube to work through the error signal. The voltage comparison circuit comprises a first depletion type NMOS tube and a first enhancement type NMOS tube. The voltage comparison function is achieved through a standard voltage generation circuit, and the domain area is reduced. The low drop-out linear voltage stabilizer has the advantages of being low in power consumption, low in noise and high in PSRR.

A low quiescent current, high PSRR, low-dropout linear regulator circuit. The circuit comprises an error amplifier (10), an adjusting component (20), a voltage dividing circuit (30), and a frequency band enhancing circuit (40). A drain electrode of the adjusting component (20) is connected to an input end of the voltage dividing circuit (30); a gate electrode of same is connected to an output end of the error amplifier (10). An output end of the voltage dividing circuit (30) is connected to an input end of the error amplifier (10). An end of the frequency band enhancing circuit (40) is connected to a substrate of the adjusting component (20). The frequency band enhancing circuit (40) forms a second path that runs from a power supply voltage end to an output end and is different from a first path that passes through the adjusting component (20). With one frequency band enhancing circuit (40) being provided in an existing low-dropout linear regulator, by generating an additional zero frequency, noise of a power supply voltage at a certain frequency point is eliminated, thus increasing the PSRR around the frequency.

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.

The invention relates to the field of integrated circuit design, in particular to an ultra-low-power-consumption non-resistance non-bandgap reference source which comprises a current source generation circuit, a threshold voltage extraction circuit, a right-temperature voltage generation circuit and a voltage superposition circuit. The bias voltage of the current source generation circuit is connected with an input end of the threshold voltage extraction circuit, an input end of the right-temperature voltage generation circuit and an input end of the voltage superposition circuit, the output end of the threshold voltage extraction circuit is connected with the other input end of the right-temperature voltage generation circuit and the other input end of the voltage superposition circuit, and the output end of the right-temperature voltage generation circuit and the output end of the voltage superposition circuit output reference voltage. The reference source has the advantage of being capable of generating a reference output voltage which is unchanged along with temperature and input voltage.

The invention relates to the technique of integrated circuits, in particular to a current reference circuit. The current reference circuit is characterized by comprising a first current reference unit, a second current reference unit and a maximum current selecting circuit, wherein the output end of the first current reference unit is connected with the first input end of the maximum current selecting circuit, the output end of the second current reference unit is connected with the second input end of the maximum current selecting circuit, and the output end of the maximum current selecting circuit is the output end of the current reference circuit. The current reference circuit has the advantages that by adopting a cascode current mirror, currents are copied more accurately, collector electrode voltage of an audion Q1 and collector electrode voltage of an audion Q2 are accurate and equal, the PSRR is improved, the current in the first current reference unit and the current in the second current reference unit are selected by adopting the maximum current selecting circuit, and therefore the temperature coefficient of the output currents is better. The current reference circuit is particularly suitable for current reference circuits.