192results about How to "High inhibition ratio" patented technology

The invention discloses a low dropout regulator, which comprises an error amplifier, a buffer circuit, a P-channel metal oxide semiconductor (PMOS) regulation transistor, an N-channel metal oxide semiconductor (NMOS) push-pull tube, a voltage division feedback circuit, a compensation circuit and an output circuit, wherein the gate of the PMOS regulation transistor is connected with the output end of the buffer circuit, the source of the PMOS regulation transistor is connected with power voltage, and the drain of the PMOS regulation transistor is used as the output end of the low dropout regulator; the gate of the NMOS push-pull tube is connected with the output end of the error amplifier, the drain of the NMOS push-pull tube is connected with the drain of the PMOS regulation transistor, and the source of the NMOS push-pull tube is grounded; and the error amplifier, the compensation circuit, the buffer circuit, the PMOS regulation transistor, the voltage division feedback circuit and an output circuit form a main control loop, and the error amplifier, the compensation circuit, the NMOS push-pull tube, the voltage division feedback circuit and the output circuit form an auxiliary control loop. According to the low dropout regulator, the transient response of the regulator can be quickened, and the accuracy of output voltage can be improved.

The invention relates to a band-gap reference circuit. The band-gap reference circuit comprises a reference voltage source VREF, a band-gap core circuit, a negative feedback circuit and a starting circuit, wherein gate voltage V_REG is stretched by the reference voltage source VREF so that internal voltage pre-stabilization can be achieved, an internal voltage pre-stabilizing circuit is formed, the band-gap core circuit is provided with an automatic biasing cascode amplifying circuit used for increasing a power supply rejection ratio, the negative feedback circuit provides the supply voltage VDD, processed through voltage stabilization, for the band-gap core circuit, and the starting circuit stretches the reference voltage source VREF when work begins so that the automatic biasing cascode amplifying circuit can work normally. According to the band-gap reference circuit, due to the facts that the supply voltage VDD processed through voltage stabilization is provided for the band-gap core circuit through the negative feedback circuit, and the automatic biasing cascode amplifying circuit is adopted inside for increasing the power supply rejection ratio, area and power consumption are saved.

The invention discloses a low noise bandgap reference circuit and a reference source generation system. The reference source generation system comprises a bandgap reference generation circuit, a low dropout linear voltage stabilizing circuit and the low noise bandgap reference circuit. The low noise bandgap reference circuit comprises a starting circuit, a clamping circuit, a temperature coefficient compensation circuit and an output circuit, wherein the starting circuit is used for supplying starting voltage to other circuits and is turned off after other circuits are started; the clamping circuit comprises four metal oxide semiconductor (MOS) tubes which are connected by a current mirror structure to realize a clamping function; the temperature coefficient compensation circuit is used for performing temperature coefficient compensation on voltage which is output by the clamping circuit and generating reference voltage which is irrelevant to temperature; and the output circuit is used for outputting second reference voltage. The reference source generation system generates extremely low noise and has high power rejection ratios.

The invention provides an ultralow temperature drift high power supply rejection ratio band-gap reference voltage source, and relates to the field of analog integrated circuit design. Mainly aimed at problems of temperature drift and power supply rejection ratio of an existing reference source, a comprehensive solution is provided. The band-gap reference voltage source comprises an independent current source circuit, a biasing circuit, a band-gap core circuit, and a PSRR enhancing circuit. The independent current source circuit is used to generate current which is basically independent of supply voltage to supply power. The bias circuit generates bias voltage used for operational amplification of the band-gap core circuit. The band-gap core circuit uses temperature compensation to obtain reference voltage. The power supply rejection ratio (PSRR) enhancing circuit provides grid bias voltage of the band-gap core circuit and improves power supply rejection ratio. Beneficial effects of the band-gap reference voltage source are that temperature coefficient of band-gap reference is greatly reduced, and power supply rejection ratio is improved. The band-gap reference voltage source is suitable to be used for a radio frequency identification power management module.

The invention provides a high-order temperature compensation band-gap reference circuit free of bipolar transistors. The high-order temperature compensation band-gap reference circuit free of the bipolar transistors comprises a front adjuster circuit, a first-order band-gap reference circuit, a low-temperature zone temperature sectional compensation circuit, a high-temperature zone temperature sectional compensation circuit and a starting circuit; a first-order band-gap reference voltage is obtained by adopting a negative-temperature-coefficient voltage VCTAT produced by a grid-source voltage of a sub-threshold NMOS (N-channel metal oxide semiconductor) transistor and a positive-temperature-coefficient voltage VPTAT produced by difference between grid-source voltages of two sub-threshold NMOS transistors, low-temperature zone temperature sectional compensation voltages (VNL1 and VNL2) and high-temperature zone temperature sectional compensation voltages (VNL3 and VNL4) are introduced into the first-order band-gap reference voltage produced by the first-order band-gap reference circuit, a band-gap reference voltage with low temperature coefficient is obtained, and a power supply rejection ratio of band-gap reference is increased with a front adjuster technology, so that the high-order temperature compensation band-gap reference circuit free of the bipolar transistors is obtained.

The invention discloses a microwave photonic band stop filter based on a Microring-Mach Zehnder interference (MR-MZI) structure, which comprises a semiconductor laser, a polarization controller, a phase modulator, an optical band pass filter, an MR-MZI integrated optical filter unit and a photoelectric detector. Narrow bandwidth filter is realized through adjusting the coupling interval between microring resonators in the MR-MZI integrated optical filter unit; through adjusting the bias voltage of each heating electrode in the MR-MZI integrated optical filter unit, the amplitude and the phase of signals are regulated; the amplitude response and the phase response of the microring are used for being combined with the MZI structure in the MR-MZI integrated optical filter unit to generate fully destructive interference, and an ultra high inhibition ratio is realized. According to the microwave photonic band stop filter provided by the invention, on the basis of the narrow bandwidth, the ultra high inhibition ratio is realized, and the microwave photonic band stop filter performance is improved.

The invention discloses a non-resistance type reference source, and belongs to the technical field of power supply management. The non-resistance type reference source comprises a starting circuit, a reference voltage generation circuit and a bias current generation circuit, wherein when a power supply is constructed, the starting circuit makes the reference source disengaged from a zero state and then retreats after starting is completed; a PMOS pipe with large threshold voltage negative temperature coefficient and an NMOS pipe with small negative temperature coefficient are selected, the negative temperature voltage in reference voltage is obtained through the threshold voltage difference of the PMOS pipe and the NMOS pipe, the positive temperature voltage is determined according to the thermal voltage, the sub-threshold slope factor and the related width-to-length ratio of the MOS pipe, and then the reference voltage VREF with good temperature characteristics can be obtained; bias currents with positive temperature characteristics are generated through the NMOS pope working in a sub-region, and the positive temperature characteristics of the currents can be enhanced when temperature rises. On the basis of traditional threshold reference, reference circuit branches are reduced, so power consumption of a reference circuit is reduced, and the power supply rejection ratio of the reference voltage is increased.

The invention provides a bandgap reference circuit with a high power supply rejection ratio and high order curvature compensation. The bandgap reference circuit comprises a starting circuit, a forward-acting regulator circuit, a bandgap circuit, a low temperature area piecewise linear temperature compensation circuit, a temperature compensation circuit with a high temperature area and the absolute temperature T1.5 in direct proportion and a high temperature area piecewise linear temperature compensation circuit. A low temperature area piecewise linear temperature compensation current and a temperature compensation current with the high temperature area and the absolute temperature T1.5 in direct proportion are added in a traditional bandgap reference circuit, a high temperature area piecewise linear temperature compensation current is drawn out of the traditional bandgap reference circuit, and accordingly the reference circuit with the high order curvature compensation is obtained; a negative feedback forward-acting regulator technology is added into reference voltage with high order curvature compensation, and accordingly the bandgap reference circuit with the high power supply rejection ratio and the high order curvature compensation is obtained.

The invention provides a cascaded microwave photonic filter-based photoelectric oscillator with a tunable broadband. The cascaded microwave photonic filter-based photoelectric oscillator comprises a first laser, a first polarization controller, a phase modulator, a first MPBF unit, a second MPBF unit, a first variable optical attenuator, a photodiode, an electric amplifier and an electric power divider which are sequentially connected, wherein a first output end of the electric power divider is used for outputting a generated microwave signal; a second output end of the electric power divideris connected with a radio frequency port of the phase modulator; when the photoelectric oscillator works, a phase modulation signal enters the first MPBF unit and then first mode selection is carriedout by using a single bandpass microwave photonic filter with the tunable broadband, thereby selecting an oscillation starting frequency of the OEO, and the phase modulation signal passes through thesecond MPBF unit and then auxiliary mode selection through an ultra-narrow bandwidth MPBF is achieved, thereby achieving single-mode oscillation starting of the OEO. A cascaded microwave photonic bandpass filter is utilized and combined with the OEO, so that single-mode oscillation starting of the OEO is achieved through multiple mode selection; and the broadband tenability of the OEO can be achieved through adjusting the central wavelength of the first MPBF unit.

The invention belongs to the technical field of wireless communication and spatial communication, and discloses a DP-MZM-based novel twelve-frequency multiplication millimeter wave generation device and method. A laser is connected with the double-parallel Mach-Zehnder modulator through a polarization controller, and the radio frequency signal source is connected with the double-parallel Mach-Zehnder modulator. The double-parallel Mach-Zehnder modulator is connected with Aphotoelectric detector through the polarization controller. According to the invention, 5GHz and 20GHz radio frequency local oscillator signals are taken, the frequency multiplication system successfully generates 60GHz and 240GHz high frequency microwave signals, and the scheme has flexible tunability; factors influencing OSSR and RFSSR are analyzed, and the feasibility of the scheme is proved. Compared with the conventional frequency multiplication scheme, the optical millimeter wave signal with higher frequency canbe generated under the condition that filtering is not needed..

This invention discloses a voltage primary circuit for a pulse width modulator including a soft start-up circuit, a band-gap primary circuit and a small current charge circuit, in which, the soft start up circuit provides suitable offset to the band-gap primary circuit to start it up smoothly, the output end of the primary signal VREFO is connected with the small current charge circuit, which uses the obtained small current to charge a rather big capacitor to rise the output signal VREF of the entire primary circuit steadily.

The invention discloses a method for detecting water pollutant biotoxicity by paper-based micro-fluidic chip anode current. The method is characterized in that a paper-based micro-fluidic chip is prepared and then water pollutant biotoxicity is determined by the paper-based micro-fluidic chip. According to a microbial respiratory chain-based BQ system electrochemical detection principle, on the paper-based micro-fluidic chip of a screen printing PDMS hydrophilic microchannel and carbon paste three-electrode system, a steam trap of the hydrophilic microchannel is dredged by a small piece of a cellulose membrane so that liquid flow release time and flowing time are controlled and separation and cleaning of a nutrient solution and cells and cell incubation by pollutants are realized and thus the interference produced by current signal detection device anode current-based quantitative determination of pollutant toxicity is reduced. The method has the advantages of light quality, carrying convenience, low cost, one-step analysis, small sample volume and fast analysis speed and is suitable for biotoxicity detection in occasions of a remote area, field on-site water pollution, soil pollution, food safety and space carrying.

The invention provides a non-periodic surface plasma grating type terahertz filter which comprises a two-dimensional metal grating flat plate with a central circular through hole. The upper surface and the lower surface of the metal grating flat plate are symmetrically provided with non-periodic annular grooves, and the widths of the annular grooves are different. According to the non-periodic surface plasma grating type terahertz filter of a bull eye structure, a non-periodic structure is adopted to remove contradictions between transmission bands and sidelobes of a general periodic filter, and the sidelobe suppression ratio is improved. Compared with a traditional filter, the non-periodic surface plasma grating type terahertz filter has the advantages of being high in center frequency transmission rate, few in loss, high in selectivity, easy to adjust, convenient to manufacture and process, low in cost and the like.

A high-PSRR (power supply rejection ratio) band-gap reference circuit with a voltage pre-stabilizing structure comprises a first starting circuit, a second starting circuit, a third starting circuit,a voltage pre-stabilizing circuit, a reference current source circuit and a band-gap reference core circuit, wherein the first starting circuit, the second starting circuit and the third starting circuit are used for starting the voltage pre-stabilizing circuit, the reference current source circuit and the band-gap reference core circuit respectively; the voltage pre-stabilizing circuit is used for generating local voltage to supply power to the second starting circuit, the third starting circuit, the reference current source circuit and the band-gap reference core circuit to realize the effect of inhibiting power ripples; the reference current source circuit is used for generating reference current, and the band-gap reference core circuit generates reference voltage. Through technologiessuch as a common-source and common-gate current mirror of the band-gap reference core circuit, a feedforward path at the output end of an operational amplifier, a third branch added to the reference current source circuit, an RC low-pass filtering circuit connected to an output end of a reference source in series and the like, the PSRR of the band-gap reference circuit is effectively improved.

The invention belongs to the technical field of electronic circuits, and particularly relates to a low-dropout regulator with the high-power-supply-rejection-ratio characteristic. Compared with an existing similar LDO, the low-dropout regulator is characterized in that the scheme that a voltage follower is additionally arranged at a power tube grid end is adopted, a low-frequency pole at the power tube grid end in a traditional LDO structure is separated into two high-frequency poles, feed-forward and feedback bandwidths are expanded, a dynamically-biased super source follower serves as output of the voltage follower, equivalent resistance at the power tube grid end under heavy loads is greatly reduced, and the inhibition performance of the low-dropout regulator to high-frequency power source noise interference is improved. A circuit structure of the low-dropout regulator maintains the high LDO efficiency, low noise and the simple circuit structure, and the power supply rejection ratio under the high-frequency condition is increased.

The invention relates to a reference current and reference voltage generation circuit with a high power-supply rejection ratio and low power consumption. The generation circuit is characterized by comprising PMOS (P-channel Metal Oxide Semiconductor) tube P1, P2 and P3, and NMOS (N-channel Metal Oxide Semiconductor) tube N1, N2, N3, N4 and N5, wherein a power supply VDD (Voltage Drain Drain) is connected with the grid electrode of the N1, the source electrodes of the P1, the P2 and the P3, and the drain electrode of the N1; the source electrode of the N1 is connected with the source electrode of the N3 and the drain electrode of the N4; the grid electrode of the N4 is connected with the grid electrode and the drain electrode of the N5 and the drain electrode of the P2; the grid electrode of the N2 is connected with the grid electrode and the drain electrode of the N3; the source electrodes of the N2, the N4 and the N5 are connected with the power GND; and the drain electrode of the P3 is used as the output end of the reference current generation circuit. The generation circuit provided by the invention is low in power consumption, low in area and high in power-supply rejection ratio.

The invention belongs to the technical field of integrated circuits, and specifically relates to a low-power consumption reference voltage source. According to the low-power consumption reference voltage source disclosed by the invention, a resistance-free design is adopted, and temperature influence of MOS (Metal Oxide Semiconductor) transistors can be removed through current-voltage and voltage-current conversion circuits; the effect of high-order temperature compensation can be achieved while positive temperature coefficient compensation is carried out, other circuits are prevented from being designed for carrying out high-order temperature compensation, and the layout area and the power consumption are reduced; meanwhile, even though a circuit adopts a cascode structure for increasing a power supply rejection ratio, the power supply voltage of the circuit still can be up to 0.9V, the power consumption is further reduced, and nanowatt level can be achieved. To sum up, the reference voltage source having low consumption, small layout area and high-order temperature compensation is realized.

The invention discloses a band-gap reference voltage source with wide input belt point curvature compensation, and the band-gap reference voltage source is mainly used for solving the problems of low source rejection ratio and low temperature stability. The band-gap reference voltage source comprises a pre-bias circuit (1), a positive and negative temperature coefficient current generation circuit (3), a voltage / current conversion circuit (4) and a reference voltage generation circuit (5). The output voltage VBIAS of the pre-bias circuit (1) is output to the positive and negative temperature coefficient current generation circuit (3), the voltage / current conversion circuit (4) and the reference voltage generation circuit (5) respectively; the current IBIAS generated by the pre-bias circuit (1) is output to the positive and negative temperature coefficient current generation circuit (3); currents I1 and I2 generated by the positive and negative temperature coefficient current generation circuit (3) are output to the reference voltage generation circuit (5); and simultaneously, the voltage VBE generated by the positive and negative temperature coefficient current generation circuit (3) is converted into a current I3 by the voltage / current conversion circuit (4) and is output to the reference voltage generation circuit (5); and the reference voltage generation circuit (5) outputsthe reference voltage VREF. The band-gap reference voltage source is high in rejection ratio and excellent in temperature stability and can be applied to an integrated circuit with wide input and high precision.

The invention discloses an operational-amplifier-free high-order low-temperature-drift bandgap reference circuit. The reference circuit comprises a starting circuit, a bias circuit, a positive temperature coefficient circuit, a negative temperature coefficient circuit, a positive temperature coefficient compensation circuit and a negative temperature coefficient compensation circuit. The operational-amplifier-free high-order low-temperature-drift bandgap reference circuit adopts an operational-amplifier-free circuit structure, and the power supply rejection ratio (PSRR) of an output referencevoltage is increased by a BJT current mirror. The circuit provided by the invention has the characteristics of wide voltage input of 12 to 36V, width-adjustable output voltage of 0 to 7V, generation of a reference voltage of 5ppm / DEG C in the temperature range of 75 to 125 DEG C, extremely low power consumption of 35mW and high-order temperature compensation.

The invention relates to a small capacitance measurement circuit based on AC (alternating current) voltage drop balance. The small capacitance measurement circuit comprises an input end excitation circuit, a measurement circuit, an output end detection circuit, and a selector switch circuit for switching input voltage direction of the input end excitation circuit to the measurement circuit; the input end excitation circuit is connected with the measurement circuit through the selector switch circuit; and the input end of the output end detection circuit is connected with a reference resistor of the measurement circuit and a to-be-measured capacitor. The invention also relates to a small capacitance measurement method based on AC voltage drop balance. The measurement method comprises the following steps: a. setting the measurement circuit provided by the invention; b. adjusting state of the selector switch circuit, and recording the frequency of an AC voltage excitation source when thevoltage amplitudes of output ends of the output end detection circuit are equal to each other; and c. deriving and calculating the capacitance of the measured capacitor. The small capacitance measurement circuit can effectively suppress the influences of AC voltage source fluctuation and external noise, well eliminate the influence of stray capacitance, effectively inhibit temperature drift, and improve the zero drift suppression capability.

The invention discloses a microwave photon mirror image rejection down conversion device and method; the method relates to the microwave technical field and the optical communication technical field; the device comprises a laser diode (LD), a dual-parallel Mach-Zehnder Modulator (DPMZM), a wavelength division multiplexer (WDM), a photoelectric detector (PD) and a quadrature coupler (Hybrid). The method uses the DPMZM to modulate a radio frequency (RF) signal and a local oscillator (LO) signal; the main modulator bias angle is set to be 45 degrees; the method uses the WDM to separate up and down optical margin belts, and an intermediate frequency (IF) signal inhibiting a mirror image frequency component can be obtained through photoelectric detection and Hybrid coupling. The microwave photon mirror image rejection down conversion device is simple in structure, wide in work frequency band width, and high in mirror image rejection ratio.

The invention discloses a phase-multiplexing-based full-range sweep frequency OCT (Optical Coherence Tomography) imaging method and system. An electrooptical modulator is arranged in a reference arm of the sweep frequency OCT system so as to realize high-speed phase modulation of an interference spectrum. Preset phase change can be kept between adjacent sampling points of the collected interference spectrum through trigger synchronization between a data collecting card and the electrooptical modulator so as to realize collection on phase multiplexing of the interference spectrum in a single sweep frequency period, the data sampling points of the collected interference spectrum are grouped according to corresponding additional phases, the grouped sampling points are respectively mapped in a wave number space with sampling points at equal intervals so as to form phase shift interference spectrum data subsets of the wave number space. Interference spectrum data can be constructed by utilizing the phase shift interference spectrum subsets so as to reconstruct full-range sweep frequency OCT images. On the basis of phase modulation and multiplexing of the interference spectrum in the single sweep frequency period of the electrooptical modulation, the phase shift is fast in speed and high in precision, the image rejection rate is high, and high-sensitivity imaging in an interesting depth area can be realized.

The invention discloses a high switching rate transconductance amplifier applied to an active power factor corrector, and mainly solves the problem that the conventional transconductance amplifier cannot timely process abnormal conditions in the active power factor corrector. The circuit comprises a bias current source, three current mirrors, a transconductance input stage and a switching rate enhancing circuit, wherein the transconductance input stage is a source cross-coupled pair; the bias current source has two paths which are respectively connected with the source cross-coupled pair, andis used for providing equal bias current is1 and is2; the switching rate enhancing circuit is connected between the three current mirrors and the source cross-coupled pair to form positive feedback in the circuit; the three current mirrors amplify current I1 and I2 output by the source cross-coupled pair and output current difference IO after comparison. The high switching rate transconductance amplifier can enlarge the maximum linear range of the output current and greatly improve the transient response speed, and can be applied to the active power factor corrector.

The invention provides a full common gate common source reference voltage source. The full common gate common source reference voltage source includes a start circuit, a reference current source circuit and a temperature compensation circuit which are connected between a power supply VDD and a ground in parallel; the starting circuit, the reference current source circuit and the temperature compensation circuit are successively connected; an output end of the start circuit is connected to the reference current source circuit, and the start circuit is used for providing start current in power-on of the power supply and allowing a reference voltage source to break away from a degeneration bias point; an output end of the reference current source circuit is connected to the temperature compensation circuit, a common source common gate current mirror is used to improve the power supply voltage rejection ratio and the voltage regulation factor, and the reference current source circuit is used for generating the reference current; and the temperature compensation circuit is used for generating low temperature drift reference voltage, the common source common gate current mirror is used to duplicate current from the reference current source circuit, and the output voltage of the temperature compensation circuit is the output voltage Vref of the reference voltage source. The full common gate common source reference voltage source is an ultra-low power consumption full cascode reference voltage source, and can suppress power source noise well.

The invention discloses a pre-regulator circuit capable of increasing band-gap reference power supply rejection ratio. The pre-regulator circuit comprises a starting circuit, a PTAT current circuit and a band-gap referent voltage generating module, wherein the PTAT current circuit comprises a PMOS transistor M5, a PMOS transistor M6, a PMOS transistor M7, a PMOS transistor M8, a transistor Q1, a transistor Q2 and a resistor R1; the band-gap reference voltage generating module comprises a PMOS transistor M9, an NMOS transistor M10, a PMOS transistor M11, a PMOS transistor M12, an NMOS transistor M13, an NMOS transistor M14 and an NMOS transistor M15. The pre-regulator circuit has the advantages that part of the noise fluctuation of power supply voltage is removed through the pre-regulator technology, the pre-regulated voltage is used as the band-gap reference power supply voltage to increase the power supply rejection ratio of the circuit, a negative feedback method is used to increase the impedance from VOUT to power supply voltage in the pre-regulator technology, and the power supply rejection ratio is further increased.

The invention provides a current mirror for effectively inhibiting power source voltage influence. The inhibiting capability of output current on power supply voltage fluctuation can be effectively improved, and the current precision is ensured. The current mirror comprises a reference current generating circuit, a first mirror image circuit, a second mirror image circuit and a current output circuit, wherein the output end of the reference current generating circuit is connected with the input end of the first mirror image circuit and the input end of the second mirror image circuit; the output end of the first mirror image circuit and the output end of the second mirror image circuit output to the current output circuit.

The invention provides a class D audio power amplifier and a modulator for class D audio power amplifier; the modulator comprises a first transconductance amplifier, a second transconductance amplifier, a capacitor and a comparator unit; wherein, the negative input end of the first transconductance amplifier is used for receiving a first audio signal and a second feedback signal of a class D amplifier, and the positive input end thereof is used for receiving reference input voltage; the negative input end of the second transconductance amplifier is used for receiving a second audio signal contrary to the first audio signal and a first feedback signal of the class D amplifier, and the positive input end thereof is used for receiving reference input voltage; the capacitor is connected between the output ends of the first transconductance amplifier and the second transconductance amplifier, and is combined with the first transconductance amplifier and the second transconductance amplifier to perform integral towards the output signal of the first transconductance amplifier and the output signal of the second transconductance amplifier; the comparator unit is used for respectively comparing the output signal of the first transconductance amplifier and the output signal of the second transconductance amplifier with the output signal of a first current source and the output signal of a second current source, and outputting a first control signal, a second control signal, a third control signal and a fourth control signal which are modulated into digital signals.

The invention discloses a low-power-consumption high-PSRR band-gap reference circuit. The low-power-consumption high-PSRR band-gap reference circuit is characterized by being composed of an operational-amplifier-free band gap core circuit, a starting circuit and a degeneration control loop; in the operational-amplifier-free band gap core circuit, the resistance value of a resistor R6 is far larger than that of a resistor R4 and that of a resistor R5, so that the base current of a transistor Q4 is low and even can be ignored, meanwhile, an operational amplifier is prevented from being used, the complexity of circuit design is lowered, and overall power consumption is further reduced; in the degeneration control loop, the voltage change of a node V2 and the electric potential errors of a node A and a node B are detected, degenerative voltages and a mirror image function of a current mirror are generated through a transistor MN2 in the loop, the influence of the supply voltage change and device mismatching on the circuits is restrained, and the stability of the band gap circuit is improved; in the starting circuit, a transistor MP4 triggers the band gap circuit to be started to work, therefore, the starting circuit can be fast switched off after the band gap circuit works normally, and power consumption of the circuit is reduced.

The invention discloses a loop circuit compensating circuit used for a Buck converter, and belongs to the technical field of electronics. The loop circuit compensating circuit used for the Buck converter comprises a leading phase compensating circuit and a full-differential low-pass filter circuit. The leading phase compensating circuit generates a zero point and two high-frequency poles to provide leading phase compensating; the full-differential low-pass filter circuit provides a pole and high lower-frequency gain; the output voltage of the leading phase compensating circuit and the output voltage of the full-differential low-pass filter circuit are added in a linear mode to acquire a voltage signal required by III-type compensating; because the high lower-frequency gain and two lower-frequency zero points are acquired, the defects that lower-frequency gain is low and steady-state errors are large in leading phase compensating are overcome. According to the loop circuit compensating circuit used for the Buck converter, because full-differential input and output structures are adopted in the leading phase compensating circuit and the low-pass filter circuit respectively, power supply rejection ratio (PSRR) is increased, the crosstalk problem among DC-DC converters in all paths of a PMU can be effectively solved.