32results about How to "Sufficient phase margin" patented technology

The invention relates to a self-adaption zero-frequency compensation circuit in a low-voltage difference linear voltage regulator. The output end of a transconductance amplifier is connected with a voltage regulation pipe by a voltage bumper, a current detection circuit is connected with the voltage bumper and the common end of the voltage regulation pipe, and the other end is connected with a variable-resistance circuit connected with the compensation end of the transconductance amplifier. In the invention, when a load is higher and current is lower, the current detection circuit can detect the load and the current and the load and the current act on the variable-resistance circuit at the moment to ensure that the resistance is enlarged, and the zero position is also relatively lower; on the contrary, when the load is reduced and the current is enlarged, the resistance value of the variable-resistance circuit is reduced, and the zero position is higher. Therefore, the self-adaption zero can change along with the change of a pole so that the compensation circuit takes the effect of compensation and effectively ensures the stable state of system operation. The compensation circuit successfully solves the problem of poor stability of a low-voltage difference linear voltage regulator so that a load capacitance equivalent series resistance is not really important to the influence on system stability, transient response and ripple waves.

In a multi-phase power converter using a phase-locked loop (PLL) arrangement for interleaving of pulse frequency modulated (PFM) pulses of the respective phases, improved transient response, improved stability of high bandwidth output voltage feedback loop, guaranteed stability of the PLL loop and avoidance of jittering and phase cancellation issues are achieved by anchoring the bandwidth at the frequency of peak phase margin. This methodology is applicable to multi-phase power conveners of any number of phases and any known or foreseeable topology for individual phases and is not only applicable to power converters operating under constant on-time control, but is extendable to ramp pulse modulation (RPM) control and hysteresis control. Interleaving of pulses from all phases is simplified through use of phase managers with a reduced number of PLLS using hybrid interleaving arrangements that do not exhibit jittering even when ripple is completely canceled.

There are provided an optical transmitter and a method for transmitting an optical signal, which realizes an optimum desired temperature arrival time without changing a Peltier element size, a drive current and a drive voltage, and which is stabilized by control having a sufficient phase margin. Different loop filters for heating and cooling are provided for a control loop of the Peltier element on which a laser diode is mounted, and the respective appropriate loop filters are selected and used on the basis of heating or cooling information.

The invention discloses a BUCK converter circuit. The BUCK converter circuit comprises a direct-current power supply used for providing a power supply voltage, a BUCK circuit used for reducing the voltage of the direct-current power supply, a LC filter used for filtering the voltage reduced by the BUCK circuit and outputting the filtered voltage to a load, a feedback sampling compensation circuit used for carrying out sampling and feedback compensation on an output voltage of the BUCK circuit and the output voltage of the LC filter, and a control circuit used for adjusting the output voltage of the BUCK circuit according to a sampling voltage of the feedback sampling compensation circuit. The stability and dynamic characteristic of the circuit are improved, and the output ripple and noise are reduced.

A method for adaptively improving the stability of an LCL grid-connected inserter system under the condition of a weak grid comprises the following steps: adding a lead correction link to the LCL grid-connected inserter system, and pre-configuring the parameters of the lead correction link; measuring the inductive impedance (Lg) of the grid through a small signal injection method; judging whether there is a need to set the parameters of the lead correction link; if there is no need to set the parameters of the lead correction link, ending the process; and if there is a need to set the parameters of the lead correction link, setting the indexing coefficient (a) and the time constant (T) of a lead network in the lead correction link, and setting the adjustment coefficient (ka) of the lead correction link. According to the invention, the lead correction link is added to the LCL grid-connected inserter system, the impedance of the grid is measured through the small signal injection method, and the parameters of the lead correction link are set to make compensation for the system phase when the phase angle margin of the system is insufficient. By adaptively adjusting the parameters of the lead correction link to make compensation for the phase margin of the system according to the result of grid impedance measurement, enough stable margin can be kept for the system, and safe and stable operation of the system can be ensured.

The invention provides a low-drop-out voltagestabilizer. The low-drop-out voltagestabilizer comprises an error amplifier, a second field effect tube, a power device, a first field effect tube and a super source follower, wherein the positive electrode input end of the error amplifier receives reference voltage, and the negative electrode input end is connected with the output end, the drain electrode of the second field effect tube is connected with the output end of the error amplifier, the source electrode of the second field effect tube is grounded through a second current source, and the grid electrode of the second field effect tube is grounded through a second current source; the drain electrode of the power device is connected to the power voltage, the drain electrode of the power device is connected with the drain electrode of the first field effect tube, and meanwhile, the power device is grounded through a first capacitor, grounded through a load current source and grounded through a third capacitor and a first current source; the grid electrode of the first field effect tube is connected with the grid electrode of the second field effect tube, the drain electrode of thefirst field effect tube is connected with the source electrode of the power device, and the source electrode of the first field effect tube is grounded through the first current source and meanwhile connected with the input end of the super source follower; the output end of the super source follower is connected with the grid electrode of the power device and meanwhile grounded through a second capacitor.

The invention discloses a gain enhanced full-differential amplifier structure for a pipeline ADC. The structure comprises an MDAC (Multiplying Digital to Analog Converter) master amplifier and two secondary amplifiers. The master amplifier is a telescopic cascode structure. Two PMOS transistors form output impedance Rp of the cascode structure. Two NMOS transistor form the output impedance Rn of the cascode structure. The two secondary amplifiers of an operational amplifier AMP1 and the operational amplifier AMP2 are used for improving the Rp and the Rn. The two secondary amplifiers comprise output voltage stabilizing structures which are used for ensuring the gate voltage stability of the common gate PMOS transistors and the common gate NMOS transistors in the operational amplifier of the full-differential master amplifier. The operational amplifier AMP1 is a two-level operational amplifier. A current input mode is taken as an input mode of a second-level amplifier. The load of a first level-amplifier is reduced. The bandwidth and gain are increased. The gain of the master amplifier is increased from original Gm1*(Rp||Rn)*A2 to Gm1*(AP*Rp||AN*Rn)*A2.

The invention discloses a double-loop filtering phase-locked loop circuit, comprising a phase detector, a double-way charge pump and a loop filtering unit which are connected in series to form a loop. The circuit also comprises a voltage and current conversion and current addition circuit unit, a current control oscillator and a frequency divider. An input end of the phase detector is connected with a reference clock signal end; the voltage and current conversion and current addition circuit unit is used for converting control voltages output by the double-way charge pump and the loop filtering unit into currents; and an output end of the frequency divider is connected with a feedback input end of the phase detector. Compared with related technologies, the double-loop filtering phase-locked loop circuit provided by the invention has the advantages that the circuit is simple in structure, low in cost, low in power consumption and high in stability.

The invention relates to a phase-locked loop compensation control circuit based on a first-order complex vector filter under a weak power grid, and belongs to the field of electronic circuits. The novel first-order complex vector filter is connected in series in front of a phase-locked loop and a common coupling point voltage feed-forward channel, and stability analysis is performed by using an equivalent impedance model of a grid-connected system. Theoretical analysis shows that the method reduces the influence of disturbance quantities such as power grid impedance and phase-locked loop bandwidth on the equivalent output impedance of the inverter, a control system can still have enough stability margin when the power grid impedance changes in a wide range, and the robustness of the grid-connected inverter is improved. Finally, the effectiveness of the method is verified through a simulation result.

The invention belongs to the field of LCL type networking converters, and discloses an LCL type networking converter control system based on a hybrid filter. Comprising a first summator, a second summator, a controller and a hybrid filter, the grid-side current given quantity is connected with the first input end of the first adder, the grid-side current output quantity is connected with the second input end of the first adder, and the input end of the controller is connected with the output end of the first adder; the first input positive end of the second adder is connected with the output end of the controller, the second input negative end of the second adder is connected with the output end of the hybrid filter, the input end of the hybrid filter is connected with different state quantities of the LCL type filter, the output end of the second adder is connected with the input end of the amplifier, and the output end of the second adder is a modulation signal. The device has the advantages of being high in damping capacity, fast in dynamic response and easy to implement.

The invention discloses a class-III compensation network and a switching power supply. The class-III compensation network comprises a voltage dividing branch and a compensation branch, the voltage dividing branch is connected between the output end and the ground, and the voltage dividing branch is provided with a voltage dividing node connected with a reference voltage; the first capacitor and the second capacitor are connected between the output end and the voltage dividing node in series, one end of the third resistor is connected to the connecting position of the first capacitor and the second capacitor, one end of the third capacitor is connected with the other end of the third resistor and the COMP end of the switching power supply, and the other end of the third capacitor is grounded. According to the III-type compensation network and the switching power supply, the voltage output by the output end can meet the requirement by adjusting the voltage dividing branch and combining the given reference voltage; the compensation branch is matched with the voltage dividing branch to carry out double-zero-point and double-pole compensation, it is ensured that when the required voltage output by the output end is small and close to the reference voltage, enough gain margin and phase margin can be achieved, and the stability of the system is ensured.

The invention discloses a driving circuit for an ultraviolet band CCD cooler. The driving circuit comprises an operational amplifier, a field effect tube, a capacitor, a first resistor, a second resistor and a third resistor; the input voltage of the driving circuit is connected with the anode of the operational amplifier; the cathode of the operational amplifier is connected with one end of the capacitor and one end of the second resistor separately; the output end of the operational amplifier is connected with the other end of the capacitor and one end of the first resistor separately; the other end of the first resistor is connected with the grid electrode of the field effect tube; the other end of the second resistor is connected with the first end of the third resistor; the second endof the third resistor is connected with the source electrode of the field effect tube; the third and fourth ends of the third resistor are connected to the ground; the drain electrode of the field effect tube is connected with the current input end of the Peltier cooler; the other end of the Peltier cooler is connected with a power supply. The driving circuit has the advantages of being simple, reliable, low in cost and capable of not generating switching noise.

The invention proposes a sampling feedback circuit of the output voltage of the switching power supply used in the switching power supply circuit, which is composed of separate components, has simple structure, strong system stability and low cost. The invention includes a voltage sampling circuit, an error amplification circuit, and an isolation conversion circuit. The output voltage Vo of the switching power supply is input through the voltage signal input terminal of the voltage sampling circuit, and the sampling signal is obtained by dividing the voltage, and the voltage input signal Vo is simultaneously used as the error amplification circuit. Power supply, the sampling signal is input through the sampling signal input terminal of the error amplifier circuit, converted into a current-type error signal and output to the error current signal input terminal of the isolation conversion circuit, and electrically isolated to obtain the feedback output signal Vfb.