44results about How to "Improve loop stability" patented technology

Apparatus is provided for treating a condition of a subject, including an electrode device, adapted to be coupled to an autonomic nerve of the subject, and a control unit. The control unit is adapted to drive the electrode device to apply to the nerve a stimulating current, which is capable of inducing action potentials in a therapeutic direction in a first set and a second set of nerve fibers of the nerve, and to drive the electrode device to apply to the nerve an inhibiting current, which is capable of inhibiting the induced action potentials traveling in the therapeutic direction in the second set of nerve fibers, the nerve fibers in the second set having generally larger diameters than the nerve fibers in the first set. Other embodiments are also described.

Apparatus is provided that includes an electrode device, adapted to be coupled to a vagus nerve of a subject, and a control unit, adapted to drive the electrode device to apply to the vagus nerve a current that reduces heart rate variability of the subject. Also provided is a method comprising applying to a vagus nerve of a subject a current that reduces heart rate variability of the subject.

A circuit for controlling a programmable power converter is provided. The circuit comprises a control circuit, a switching controller, and a first opto-coupler. The control circuit generates a programmable voltage-reference signal for regulating an output voltage of the programmable power converter. A feedback circuit of the control circuit detects the output voltage for generating a feedback signal in response to the programmable voltage-reference signal and the output voltage. The switching controller detects a switching current of a transformer for generating a switching signal coupled to switch the transformer for generating the output voltage and an output current in response to the feedback signal and the switching current of the transformer. The first opto-coupler transfers the feedback signal from the control circuit to the switching controller. The control circuit is at the secondary side of the transformer and the switching controller is at the primary side of the transformer.

The invention belongs to the field of the integrated circuit design, and especially relates to a low-dropout linear voltage stabilizer based on self-adaptive zero compensation. The low-dropout linearvoltage stabilizer comprises a reference voltage circuit, an error amplifier, a serial adjusting pipe and a feedback network composed of a first resistor and a second resistor, and further comprises aload current induced circuit, a self-adaptive compensation control circuit, a zero-setting resistor connected with a drain terminal of the serial adjusting pipe and a compensation capacitor connectedwith a grid terminal of the serial adjusting pipe; the load current induced circuit samples load current, the self-adaptive compensation control circuit produces voltage for controlling the zero-setting resistance by using the sampled current, the zero-setting resistance value dynamically follows the change of the load current, thereby realizing the change, following the output pole, of the related zero point, acquiring self-adaptive frequency compensation, and improving loop stability of the voltage stabilizer; therefore, under the condition of not increasing relatively large static power consumption and compensation capacitance, the low-dropout linear voltage stabilizer can maintain the loop stability in the wide load current range.

The invention discloses a self-biasing phase-locked loop. The self-biasing phase-locked loop comprises a phase frequency detector, a charge pump, a loop filter, a voltage controlled oscillator and a frequency divider. The charge pump can receive control voltage from the loop filter and adjust charging or discharging current to be in the linear relationship with the control voltage. The voltage controlled oscillator can generate an output signal according to the inputted control voltage and adjust the frequency of the output signal to be proportional to the control voltage. According to the self-biasing phase-locked loop, the charging or discharging current of the charge pump is adjusted to be in the linear relationship with the control voltage, and the frequency of the output signal of the voltage controlled oscillator is adjusted to be proportional to the control voltage so that the open loop gain, the loop closed damping factor and the natural attenuation frequency of the phase-locked loop are enabled not to change along with the change of the frequency, and the self-biasing phase-locked loop is enabled to have great loop stability.

An oscillator arrangement comprises a current controlled oscillator, a frequency to voltage converter, and an operational amplifier. The current controlled oscillator is adapted to generate a clock signal based on a control voltage signal, wherein the generated clock signal is supplied to the frequency to voltage converter. The frequency to voltage converter is adapted to generate an output voltage signal based on the generated clock signal and based on a supply voltage signal.

The invention relates to a COT control-based internal ripple compensation circuit and a control method thereof. A division voltage of an output end voltage of the circuit is used as a feedback voltagefor being acted on a comparator, the feedback voltage is compared with a reference voltage of the comparator, an output signal obtained by the comparator is acted on a RS trigger to control conduction of a power tube or a rectification tube, the power tube is conducted, the rectification tube is cut off and energy is stored in an inductor when the output end voltage is lower than a preset voltageand the feedback voltage is lower than the reference voltage, a conduction time control circuit starts to time, the RS trigger is controlled by the conduction time control circuit after preset time is reached, so that the power tube is cut off, the rectification tube is conducted, energy is released to an output capacitor from the inductor, the ripple compensation circuit generates a ripple voltage, the feedback voltage is larger than the reference voltage by the ripple voltage, and subharmonic oscillation of the circuit caused by excessively small series resistance of the output capacitor isprevented.

The invention discloses a band-pass feed-forward sigma-delta modulator. The modulator comprises three cascaded switched-capacitor resonator modules, an adder module, a quantizer module and a feedback digital to analog conversion (DAC) module. In the sigma-delta modulator, a feed-forward structure is adopted instead of a common feedback structure, and input ends of resonators only include quantization noise components rather than input signal components, so that input levels of the resonators are lowered, and the loop stability of the whole sigma-delta modulator is enhanced. Thus, the band-pass feed-forward sigma-delta modulator disclosed by the invention is suitable for an analog to digital converter with a high-order single-loop structure, and the requirements of a modulator circuit for analog sub-circuits such as operational amplifiers are lowered. As indicated by a simulation result, the band-pass feed-forward sigma-delta modulator disclosed by the invention reach a dynamic signal-to-distortion ratio range from 96.8dB to 106dB under the conditions of a power supply voltage being 3.3V, a clock frequency being 800KHz, a central frequency being 200KHz and a signal bandwidth being 5KHz, and meets the application requirements of micro mechanical sensor systems such as high-accuracy gyroscopes and acceleration sensors.

The invention provides a passive-control high-frequency signal-injected permanent magnet synchronous motor positionless sensor control system and a control method and belongs to the motor control field. The system comprises a first coordinate conversion unit, a high frequency response signal separation unit, a PLL speed observer, a soft switch passive rotation speed current regulator, a second coordinate conversion unit and a modulation unit, wherein the first coordinate conversion unit converts a three-phase current of a permanent magnet synchronous motor into a d-axis current and a q-axis current; the high frequency response signal separation unit combines a d-axis current, a q-axis current, and a high-frequency injection voltage signal to generate a high frequency response error signal;the PLL speed observer obtains a motor rotation speed estimation value and a position estimation value; the soft switch passive rotation speed current regulator obtains a d-axis voltage given value and a q-axis voltage given value; the second coordinate conversion unit forms a modulation given voltage; and the modulation unit carries out 3D-SVPWM modulation on a modulation voltage to obtain a duty cycle signal, and the duty cycle signal is sent to a driving circuit to generate a driving waveform. The system and the method have advantages that power density is large; operation reliability is high; and production efficiency is high too.

The invention discloses a low noise transimpedance amplifier. The amplifier comprises a main amplifier, an auxiliary amplifier, a transimpedance, two current sources, and a source follower. The main amplifier and the auxiliary amplifier adopt a cascode structure. The drain electrode of a common-source field-effect tube of the main amplifier is connected to the input end of the auxiliary amplifier.The output end of the auxiliary amplifier is fed back to the grid electrode of the common-grid field-effect tube of the main amplifier. The two current sources inject currents into the drain electrode of the common-source field-effect tube of a dual-stage amplifier. The input end of the source follower is connected to the output end of the main amplifier. The output end of the source follower isthe signal output end of the transimpedance amplifier. In the invention, main and auxiliary cascode amplifiers and a similar gain-boost structure are used to reduce a noise, and the two current sources inject the currents into the common-source field-effect tube so as to further reduce the noise; and a current gain control structure is used to adjust an excessive input current signal gain so thatthe dynamic range of a circuit is increased.

A phase-locked loop circuit and a communication chip belong to the field of integrated circuits, and a modulation circuit outputs a first feedback current and a second feedback current according to a modulation voltage and a frequency division control signal; a phase frequency detector detects a phase difference between an input clock signal and a first clock signal and generates a first control signal; a charge pump performs charging and discharging according to the first control signal and the second feedback current so as to output a first control voltage; a main loop filter adjusts an adjustable resistor in the main loop filter according to the first feedback current so as to modulate the first control voltage and generate a modulation voltage; a voltage-controlled oscillator outputs an output clock signal of which the frequency is in direct proportion to the modulation voltage; a feedback frequency divider performs frequency division of a preset frequency division ratio on the output clock signal according to the frequency division control signal so as to output a first clock signal; the square root of the preset frequency dividing ratio divided by the quotient of the second feedback current is a first coefficient, and the ratio of the resistance value of the adjustable resistor to the first coefficient is a constant; the loop stability of the phase-locked loop is improved.

The invention discloses a switching power supply, and a control circuit and a control method thereof. The switching power supply converts an input voltage into an output voltage through switching on and switching off of the switch so as to provide the output voltage to a load. The control circuit uses an error amplification circuit to form a control loop to control on and off of the switch, and the error amplification circuit comprises a first input end, a second input end and an output end. The control circuit couples a first compensation resistance network between the first input terminal and the output terminal of the error amplification circuit or couples a second compensation resistance network at the first input terminal of the error amplification circuit. The control circuit also detects whether the switching power supply enters a transient state, and if the switching power supply enters the transient state, the first resistance value of the first compensation resistance network is increased or the second resistance value of the second compensation resistance network is reduced. The control circuit provided by the invention can enable the switching power supply to have better loop stability in a steady state and improve the transient response performance of the switching power supply in a transient state.

An amplifier circuit includes an operational amplifier and a compensation circuit. The operational amplifier includes an amplifying stage for amplifying an input signal to generate an amplifying signal; and an output stage coupled to an output node of the amplifying stage for receiving the amplifying signal and generating an output signal according to the amplifying signal. The compensation circuit is coupled to the output stage and the amplifying stage for generating a compensation signal according to the output signal, and feeding the compensation signal back to the output node of the amplifying stage for compensating the amplifying signal.

The invention relates to the technical field of electrical electrons, in particular to a power source system with a stable loop. The power source system comprises a pulse width modulating driver, a PMOS pipe, an NMOS pipe, a first comparator, a first diode, a second diode, a first resistor, a second diode, a second resistor, a first capacitor and a current limiting protection circuit; a positive electrode of the first diode is connected with a comparison output end; one end of the first resistor is connected with a negative electrode of the first diode; a positive electrode of the second diodeis connected with the negative electrode of the first diode; the two ends of the second resistor are connected with a negative electrode and the comparison output end of the second diode; one end ofthe first capacitor is connected with the first resistor and is not connected with the first diode. The high loop stability can be guaranteed, and the reliability is high.

The invention discloses a broadband voltage-controlled oscillator supporting low-gain change, and belongs to the technical field of semiconductor integrated circuits. The broadband voltage-controlled oscillator comprises an inductor assembly (1), a switched capacitor array (2), a varactor unit (3) and a compensation loop (4) which are connected in parallel. The varactor unit (3) comprises a variable bias varactor unit (31) and a switch varactor unit (32), the variable bias varactor unit (31) is used for adjusting the fine tuning gain change of the broadband voltage-controlled oscillator, and the switch varactor unit (32) is used for adjusting the coarse tuning gain change of the broadband voltage-controlled oscillator. The voltage-controlled oscillator is wide in output frequency range and small in tuning gain change.