5 results about "Negative feedback amplifier" patented technology

This invention provides a passive infrared detection device that can shorten power-on time. The passive infrared detection device includes a pyroelectric infrared sensor and an amplifier circuit. The amplifier circuit uses a non-inverting negative feedback amplifier circuit powered by dual power supplies as the primary amplifier circuit. A step-down voltage divider circuit is configured to pull down the DC bias voltage of the detection signal output from the signal output terminal of the pyroelectric infrared sensor. In this way, at the beginning of power-on of the passive infrared detection device, there is a small voltage difference between the non-inverting and inverting input terminals of the operational amplifier of the primary amplifier circuit. This reduces the time required for the voltage between the non-inverting and inverting input terminals of the operational amplifier to become consistent during the charging and discharging process, thereby shortening the power-on time of the primary amplifier circuit.

The invention relates to the technical field of circuit control, and discloses an automatic and manual control analog circuit based on servo motor loading, which is based on a negative feedback amplification circuit and is characterized by comprising an automatic control module and a manual control module, the automatic control module and the manual control module both adopt an LF347N chip as a signal processing core. According to the invention, an automatic control module and a manual control module based on a negative feedback amplification circuit are constructed, precise signal processing is realized by means of an LF347N chip, mode isolation is realized by means of a DS2Y-S-DC12V relay, the automatic module completes closed-loop loading control through comparison of a command signal and a load feedback signal, and the load feedback signal is compared with the manual control module through the DS2Y-S-DC12V relay. The manual module realizes loading speed adjustment through an external potentiometer, fills the blank of a servo motor loading special control circuit in an existing servo control system, meets the dual requirements of an industrial scene for loading control accuracy and flexibility, and avoids the limitation that a single control mode cannot adapt to complex working conditions.

This invention discloses a sensor output conversion circuit, comprising: a conditioning chip, a voltage regulator, a path controller, and a negative feedback amplifier circuit. The negative feedback amplifier circuit includes an operational amplifier electrically connected to a first resistor, a second resistor, and a third resistor, used to convert a conditioned output signal in a first voltage range into a conditioned signal output in a second voltage range. This invention utilizes the virtual ground, near-infinite input impedance, and near-infinite common-mode rejection ratio of the operational amplifier to convert a conditioned output signal in the 0-5V range into a conditioned signal output in the 0-10V range, achieving a linear electrical connection between the sensor circuit and the industrial equipment circuit. Furthermore, by selecting components with different parameters and switching paths using the path controller, the initial signal calibration and conditioned signal output of the front-end conditioning chip can be conveniently achieved.

One aspect can provide a direct current (DC) feedback circuit. The DC feedback circuit can include a gain path, a first feedback capacitor coupled, in parallel, to the gain path, and an input resistor coupled to an input of the gain path and the first feedback capacitor. The gain path can include an input stage with a pair of transconductance amplifiers, a gain stage with one or more amplifiers, and an output stage with at least one negative feedback amplifier.

The invention discloses an anti-interference receiving front-end circuit, which comprises a current mode anti-interference transconductance amplifier, a down-conversion switching network and a first-order RC (Resistance-Capacitance) filtering transimpedance amplification network, the current mode anti-interference transconductance amplifier is used for converting a radio frequency input voltage signal into a radio frequency current; the down-conversion switching network is used for converting the radio-frequency current into an intermediate-frequency current; the first-order RC filtering transimpedance amplification network is used for filtering high-frequency clutter components in the intermediate-frequency current, converting the intermediate-frequency current into intermediate-frequency voltage and outputting the intermediate-frequency voltage; the current mode anti-interference transconductance amplifier adopts a current multiplexing active negative feedback amplifier structure, the down-conversion switch network adopts a passive double-balance frequency conversion switch circuit, and the first-order RC filtering transresistance amplification network comprises a differential operational amplifier and a first-order RC low-pass filter. According to the invention, when the adjacent channel interference power reaches 0dBm, the receiving front end can obtain gain compression less than 3dB and a noise coefficient superior to 10dB, so that the anti-interference capability is greatly improved.