摘要:
An RF microwave power transistor has an input/output feed structure which functions as a low impedance microstrip line by providing a ground plane in close proximity to the feed structure on one surface of a semiconductor body. A second ground plane can be provided on an opposing surface of the semiconductor body with vias interconnecting the first and second ground planes. In addition to reducing feed impedance, a larger total transistor size can be provided before “odd mode oscillation” occurs.
摘要:
In an RF amplifier circuit having a plurality of transistor stages with each transistor having an input terminal for receiving an RF signal, a bias circuit is provided for applying a DC bias to the input terminal of a transistor. An isolation circuit connects a DC power supply to a bias circuit whereby DC voltage from the power terminal is applied to the bias circuit and RF signal from the transistor input terminal is attenuated. The isolation circuit includes a reactive serial path which allows the flow of DC current and presents an impedance to RF current flow and a reactive shunt path to ground which can comprise a capacitor or a serial inductor/capacitor circuit. The reactive serial path can comprise an inductor or an inductor/capacitor parallel circuit.
摘要:
A temperature compensating circuit for use with a current mirror circuit for maintaining a reference current value during temperature variations includes a compensating transistor connected in parallel with a reference current transistor and bias circuitry for biasing the compensating transistor whereby current flows from the reference node to ground through the compensating transistor to remove excess current from the reference transistor when temperature increases. A diode can be included in the bias circuitry for limiting bias current flow when the reference voltage drops below the voltage drop of the diode. An on/off switch circuit can be provided in parallel with the reference current transistor to further reduce reference current in specific applications.
摘要:
A hybrid microwave and millimeter wave integrated circuit (MMIC) RF power amplifier includes an integrated circuit in which an amplifier circuit is fabricated and an output impedance matching network comprising metal-insulator-metal (MIM) capacitors mounted on the integrated circuit chip with bonding wire inductors connecting the amplifier circuit with the capacitor elements. The resulting structure has a smaller form factor as compared to conventional power amplifiers employing planar transmission lines and surface mount technology capacitors.
摘要:
Efficiency of an RF/microwave power amplifier is increased at a back-off power level by increasing the load resistance of the amplifier at the reduced output power level as compared to load impedance at a higher power level including full operating power. The different load impedances can be realized with two amplification units in parallel each having different load impedances. Alternatively, a single amplification path can be provided with an output impedance matching network which is selectively bypassed for increased impedance load during back-off power operation. In another embodiment, the output impedance matching network can include a shunt inductance which is selectively switched into the network to increase impedance for back-off power operation.
摘要:
A signal processing apparatus for a multi-mode satellite positioning system includes a band-pass filter, a local oscillator circuit, a first mixing circuit, a second mixing circuit, an analog-to-digital converter and a baseband circuit. By properly allocating a local frequency, radio frequency (RF) signals of a Global Positioning System (GPS), a Galileo positioning system and a Global Navigation System (GLONASS) are processed via a single signal path to save hardware cost.
摘要:
A multi-modulus divider and a method for performing frequency dividing by utilizing a multi-modulus divider are disclosed. The multi-modulus divider comprises a multi-modulus dividing circuit, a pulse generating circuit, and a modulus signal generating circuit. The multi-modulus dividing circuit comprises several serially connected divider cells, of which a predetermined one may be bypassed. The multi-modulus dividing circuit generates an output frequency according to an input frequency and a divisor. A range of the divisor comprises a plurality of numerical intervals. The pulse generating circuit generates a pulse signal. The modulus signal generating circuit generates a determination result by determining which numerical interval the divisor belongs to, and inputs, according to the determination result, the pulse signal into the predetermined divider cell to be one of references which the predetermined divider cell refers to when outputting a modulus signal. The predetermined divider cell corresponds to the determination result.
摘要:
A mixer in a smaller signal differential model includes a load circuit, a switch quad, and a transconductor. The switch quad further including a first current path and a second current path is coupled to the load circuit. The connecting node of the switch quad and the load circuit is a differential-output terminal. The transconductor further includes a first resistor, a first operational amplifier, a second operational amplifier, a first current mirror, and a second current mirror. The resistor is coupled between two first input terminals of the first operational amplifier and the second operational amplifier. A current control terminal of the first current mirror is coupled to the first input terminal of the first operational amplifier, and a current mirroring terminal of the first current mirror is coupled to the first current path. A current control terminal of the second current mirror is coupled to the first input terminal of the second operational amplifier, and a current mirroring terminal of the second current mirror is coupled to the second current path. A differential voltage is applied between two second input terminals of the first operational amplifier and the second operational amplifier.
摘要:
A mixer using a small signal differential model includes a load circuit, a switch quad, and a transconductor. The switch quad further including a first current path and a second current path is coupled to the load circuit. The connecting node of the switch quad and the load circuit is a differential-output terminal. The transconductor further includes a first resistor, a first operational amplifier, a second operational amplifier, a first current mirror, and a second current mirror. The resistor is coupled between two first input terminals of the first operational amplifier and the second operational amplifier. A current control terminal of the first current mirror is coupled to the first input terminal of the first operational amplifier, and a current mirroring terminal of the first current mirror is coupled to the first current path. A current control terminal of the second current mirror is coupled to the first input terminal of the second operational amplifier, and a current mirroring terminal of the second current mirror is coupled to the second current path. A differential voltage is applied between two second input terminals of the first operational amplifier and the second operational amplifier.
摘要:
A proportional to absolute temperature (PTAT) sensor is capable of reducing a sensing error resulted from a mismatch between circuit components. The PTAT sensor includes a control unit, a sensing unit and a calculation unit. The control unit generates a control signal. The sensing unit, comprising at least a pair of circuit components having a matching relationship, senses an absolute temperature under the first connection configuration and the second connection configuration respectively to generate a first voltage value and a second voltage value, wherein the first connection configuration and the second connection configuration are decided by interchanging the circuit connections of the pair of circuit components according to the control signal. And the calculation unit, coupled to the sensing unit, calculates a PTAT voltage value according to the first voltage value and the second voltage values.