40results about How to "High loop gain" patented technology

Disclosed are methods and circuits for providing a bandgap reference in an electronic circuit having a supply voltage and ground. The methods include steps for generating a bandgap reference current, mirroring the bandgap reference current, summing the mirrored currents, and modulating and outputting a bandgap reference voltage from the sum. Representative preferred embodiments are disclosed in which the methods of the invention are used in providing under-voltage protection and in providing a regulated output voltage. Circuits are disclosed for a bandgap reference voltage generator useful for providing a bandgap reference voltage in a circuit. A first current mirror for provides current from a supply voltage. A bandgap reference current circuit between the first current mirror and ground is configured for deriving a bandgap current proportional to absolute temperature. A second current mirror and control circuit are provided for summing the mirrored currents and modulating a bandgap reference voltage output. Preferred embodiments of the invention include a bandgap under-voltage detection circuit using a comparator and a voltage regulator circuit having a regulated voltage output capability.

The invention relates to a bias current generating circuit which comprises a loop unit, an output unit and an amplifying unit. The loop unit comprises a first PMOS pipe, a second PMOS pipe, a first NMOS pipe and a second NMOS pipe, wherein a first current mirror structure is formed by the first PMOS pipe and the second PMOS pipe, a second current mirror structure is formed by the first NMOS pipe and the second NMOS pipe, and the first NMOS pipe and the second NMOS pipe are operated in a sub-threshold value zone; the output unit is used for outputting a bias current; the amplifying unit comprises the first input end and the output end, the first input end is connected to a source electrode of the first NMOS pipe or a source electrode of the second NMOS pipe, the output end is respectively connected to a grid electrode of the first PMOS pipe and a grid electrode of the second PMOS pipe. According to the technical scheme, the influence on the output of the bias current generating circuit by the temperature can be reduced.

The present invention provides an optical transmitter that prevent the overshoot and undershoot appeared in the emission wavelength caused by the fluctuation of the temperature of the laser diode installed therein. The optical transmitter includes a TEC driver, and a master controller. The TEC driver, by comparing the monitored temperature with the target temperature, outputs the error signal to the master controller, which enables the LD-Driver only when the error signal continuously stays within a convergent range by a preset period.

A self-oscillating amplifier system is disclosed. The system comprises a pulse modulator, a switching power amplification stage and a demodulation filter. Moreover, the system comprises a compensator including a forward filter which is a high order filter including a second order pole pair and a second order zero pair. Hereby it is possible to decrease the phase turn at low frequencies for better stability and increasing the gain of the control loop within the desired bandwidth.

Described herein are several configurations of Class-D audio amplifiers, including a single-ended and a bridge-tied load (BTL) configuration, in which voltage-mode control and average current-mode control circuitry in feedback loops can be included to control the outputs of the Class-D amplifier to reduce open-loop errors and maintain a relatively high loop gain over an expected audio frequency range. The average current-mode control circuitry monitors current through a resistor common to both a current flow into a positive terminal of a loudspeaker associated with the amplifier and a current flow into a negative terminal of the loudspeaker. The voltage-mode control circuitry works with the average current-mode control circuitry in controlling the output of the Class-D audio amplifier.

The invention provides an X-band satellite-borne phase-locked receiver. The X-band satellite-borne phase-locked receiver comprises a receiving link front end, a main phase discriminator, a loop filter and a voltage-controlled oscillator and further comprises a loop gain control device, wherein the receiving link front end is used for inputting a received signal, performing down-conversion of the received signal according to a frequency conversion reference signal output by the voltage-controlled oscillator, and outputting an intermediate-frequency signal; the main phase discriminator is used for receiving the intermediate-frequency signal and the frequency conversion reference signal, performing phase discrimination of the intermediate-frequency signal according to the frequency conversion reference signal, and outputting a direct-current voltage signal and an alternating-current difference beat signal to the loop filter; the loop filter is used for removing the alternating-current difference beat signal by filtration and outputting the direct-current voltage signal to the voltage-controlled oscillator; the voltage-controlled oscillator is used for outputting the frequency conversion reference signal under the control of the direct-current voltage signal; and the loop gain control device is used for performing phase discrimination of the phase-shift intermediate-frequency signal according to the frequency conversion reference signal, and controlling the direct-current gain of the loop filter to be increased when phases are same. By means of the X-band satellite-borne phase-locked receiver disclosed by the invention, the problems that the nondeterminacy of the selective static frequency of the X-band phase-locked receiver is relatively high and the scanning time of a ground measurement and control station is relatively long in the existing aerospace vehicle can be solved.