The invention discloses a bandwidth-adjustable operational amplifier circuit. The operational amplifier circuit comprises a bias circuit, a fully differential operational amplifier main circuit and a common mode feedback circuit, wherein the bias circuit is used for providing stable bias current irrelevant to temperature and a process for the fully differential operational amplifier main circuit and the common mode feedback circuit; the fully differential operational amplifier main circuit is of a two-stage amplifying rail-to-rail output structure, and is used for providing gain and required bandwidth under the action of the bias current and outputting a common mode level to the common mode feedback circuit; and the common mode feedback circuit is used for stabilizing the common mode level output by the fully differential operational amplifier main circuit to a constant voltage. The bandwidth-adjustable operational amplifier circuit disclosed by the invention can be widely applied to radio frequency and analogue integrated circuits, such as active power filters, trans-impedance amplifiers and the like which need to work under various bandwidths. The bandwidth-adjustable operational amplifier circuit has the advantages that the power consumption is low, the integration level is high, the configuration is simple, and the working is stable, and adapts to various different load conditions.

Bandwidth-adjustable operational amplifier circuit

The invention relates to the field of electrics, in particular to a linear voltage regulator with a built-in compensation capacitor. The linear voltage regulator is characterized by comprising an operational amplifier, an EA (Error Amplifier), and a quick response LDO (Low Dropout Regulator). The invention is an integrated power supplying IP for chips such as a high-performance central processor, a digital signal processor, a programmable logic device, and a high-performance converter and provides the linear voltage regulator with the built-in compensation capacitor; without an external large compensation capacitor, the stable work of the system can be guaranteed with adoption of a parasitic capacitor in the processor, and the integration with large-scale digital circuit chips can be achieved conveniently.

Linear voltage regulator with built-in compensation capacitor

The invention discloses a fully integrated dual-band configurable radio-frequency power amplifier, belonging to the technical field of wireless communication. In the invention, a cascode amplifier structure is adopted, an LC (Inductance-capacitance) resonant network is taken as a load, and the resonant network consists of 6 MOS (Metal-oxide Semiconductor) transistors M1-M6, 4 capacitors C1-C4, 2 inductors L1-L2 and 2 resistors R1-R2. Different induction values are supplied at a high frequency band and a low frequency band to be resonant to the capacitors, and therefore, the amplifier can bothsupply higher gains at the high frequency band and the low frequency band. Meanwhile, the amplifier does not introduce a switch with larger loss on a signal channel, thereby avoiding that the efficiency of the radio-frequency power amplifier is lowered because of switch loss. The novel dual-band configurable radio-frequency power amplifier can be completely integrated on a same chip, thereby realizing high integration level. The invention can both supply high gains in two frequency bands with a large frequency difference and also have high efficiency.

Fully integrated dual-band configurable radio-frequency power amplifier

The invention relates to a differential operational amplifier by using active feed-forward circuit for frequency compensation, and mainly solves the technical problems that the zero pole separation of a multistage differential operational amplifier is caused as the current Miller frequency compensation method introduces Miller capacitance, and further unity-gain bandwidth of the differential operational amplifier is limited. According to the technical scheme, the differential operational amplifier comprises a first gain stage, a second gain stage and an active feed-forward amplification stage, wherein each of the first gain stage and the second gain stage comprises a first input node and a second input node; the active feed-forward amplification stage is composed of a circuit A (a control node is coupled to the first input nodes, and a control path is coupled to a second output node;) and a circuit B (a control node is coupled to the second input nodes, and a control path is coupled to a first output node;). The differential operational amplifier further comprises a common-mode negative feedback circuit, wherein the common-mode negative feedback circuit is composed of a high gain stage and an active feed-forward amplification stage. The unity-gain bandwidth performance of the fully differential operational amplifier can be effectively improved, and chip implementation area is reduced.

Differential operational amplifier by using active feed-forward circuit for frequency compensation

The invention, belonging to the technical field of design of analogue integrated circuit, discloses a partial common mode feedback fully differential operational amplifier with starting circuit. The circuit comprises a basic two-stage operational amplifier main circuit, a partial common mode feedback circuit and a starting circuit; and the starting circuit comprises a state detection circuit, a reset circuit and a bias switch circuit. The partial common mode feedback fully differential operational amplifier with starting circuit can solve the problem that traditional partial common mode feedback fully differential operational amplifier cannot work normally in some applications. The starting circuit can detect non normal working state of the circuit, and the reset circuit makes the operational amplifier come to normal working state. The bias switch circuit in the starting circuit can avoid competition between the reset circuit and the fixed bias load tube in the partial common mode feedback circuit in the circuit starting process. The partial common mode feedback fully differential operational amplifier with starting circuit is suitable for the circuit having need of using the fully differential operational amplifier.

Partial common mode feedback fully differential operational amplifier with starting circuit

The invention discloses a common-mode feedback circuit frequency compensation method of a dual-stage amplifier, which belongs to the analog integrated circuit design field One common-mode feedback circuit is adopted in the dual-stage amplifier to reduce the area and the power consumption of the feedback circuit; the dual-stage amplifier adopts a fully-differential input/output structure; a differential output terminal is used for sampling the common-mode output level; a first-stage amplifying circuit thereof comprises a controllable biasing circuit; a common-mode feedback control signal controls the first-stage common-mode output level and the second-stage common-mode output level of the amplifier at the same time through the controllable biasing circuit; a feedback amplifier is realized by adopting a dual-stage operational amplifier with miller compensation The left half plane zero point generated by the feedback amplifier in a loop circuit counteracts a certain left half plane pole in a prime amplifier, thereby forming a stable compensation loop circuit The common-mode feedback circuit frequency compensation method has the advantages of less feedback circuit elements, lower feedback circuit power consumption, high low-frequency loop gain and better compensation phase margin

Chun Zhang

Papers

Method for compensating common mode feedback circuit frequency of two-stage amplifier