Mixer of communication system
AssigneeMacronix International Co., Ltd.
InventorTzung-Hsiung Wu
Life of this patent
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Abstract
A mixer of a communication system. The communication system has an antenna, low noise amplifier, a mixer, a local oscillator and an intermediate frequency filter. The mixer has a mixer circuit, a gain amplified circuit, a voltage auto-tracking circuit and a direct current voltage generating circuit. The direct current voltage generating circuit can reduce the output power of the local oscillator, extend the lifetime of the battery used in the mobile communication system, and reduce the distortion of harmonic wave of the local oscillator to reduce the noise figure of the mixer. Using the voltage auto tracking circuit and the gain amplified circuit, the linearity of the mixer is enhanced, and the conversion gain of the mixer is adjusted by varying the load resistors.
Claims13
A mixer of a communication system, the communicating system comprising an antenna, a low noise amplifier, the mixer, a local oscillator and an intermediate frequency filter, the mixer comprising:
- a mixer circuit, to perform a multiplication on a radio frequency received from the antenna and a radio frequency signal generated by the local oscillator;
- a gain amplified circuit, coupled to a power supply terminal of the mixer circuit to increase a linearity of the mixer circuit;
- a voltage auto-tracking circuit, coupled to an output terminal of the gain amplified circuit to control a direct current output from an output terminal of the gain amplified circuit;
- and
- a direct current voltage generating circuit, coupled to an input terminal of a local oscillator of the mixer circuit to generate a fixed threshold voltage.
A mixer of a communication system, wherein the communication comprises an antenna, a low noise amplifier, the mixer, a local oscillator and an intermediate frequency filter and the mixer comprises a mixer circuit, a voltage auto-tracking circuit, a gain amplified circuit and a direct current voltage generating circuit, the voltage auto-tracking circuit coupled to an output terminal of the mixer circuit to control a direct current output from the output terminal of the mixer, the voltage auto-tracking circuit comprising:
- a resistor, with one terminal coupled to an output terminal of the gain amplified circuit;
- a capacitor, with one terminal coupled to the other terminal of the resistor and the other terminal coupled to ground;
- an operation amplifier, with a positive terminal coupled to the other terminal of the resistor and a negative terminal coupled to a reference voltage, the operation amplifier controlling a direct current output from an output terminal of the gain amplified circuit;
- and
- an NMOS, with a drain coupled to a power source, a source coupled to the output terminal of the gain amplified circuit, a gate coupled to the output terminal of the operation amplifier, and a base coupled to the source of the NMOS that provides a direct current.
The mixer according to 5, wherein the direct current voltage generating circuit further comprises:
- a first PMOS, having a source coupled to the power source, and a base and a drain coupled to each other;
- a first NMOS, having a drain coupled to the drain of the first PMOS, a gate and coupled to the drain of the first NMOS, and a base and a source coupled to each other;
- a second NMOS, having a drain coupled to the source of the first NMOS, a gate coupled to the drain of the second NMOS, and a base and a source coupled to each other;
- a second PMOS, having a source coupled to the power source, a gate coupled to the gate of the first PMOS, a drain coupled to the gate of the second PMOS, and a base coupled to the drain of the second PMOS;
- a third NMOS, having a drain coupled to the drain of the second PMOS, a gate coupled to the gate of the first NMOS, a base and a source coupled to each other;
- a fourth NMOS, having a drain coupled to the source of the third NMOS, a gate coupled to the gate of the second PMOS, a source coupled to the source of the second NMOS, and a base coupled to the source to the fourth NMOS;
- a fifth NMOS, having a drain coupled to the source of the fourth NMOS, a gate coupled to a bias power source, a source couple to ground and a base coupled to the source of the fifth NMOS;
- a third PMOS, having a source coupled to the power source, a gate coupled to the drain of the second PMOS, a drain coupled to the output terminal of the direct current voltage generating circuit, and a base coupled to the drain of the third PMOS;
- and
- a sixth NMOS, having a drain coupled to the drain of the third NMOS, a gate coupled to the drain of the sixth NMOS, a source coupled to the source of the third NMOS and a base coupled to the source of the sixth NMOS.
A mixer of a communication system, wherein the communication comprises an antenna, a low noise amplifier, the mixer, a local oscillator and an intermediate frequency filter and the mixer comprises a mixer circuit, a voltage auto-tracking circuit, a gain amplified circuit and a direct current voltage generating circuit, the gain amplified circuit is coupled to a power supply terminal of the mixer circuit to increase an output gain of the mixer circuit, the gain amplified circuit comprising:
- a first current mirror circuit, further comprising:
- an impedance with one terminal coupled to the power source and the other terminal coupled to a first power input terminal of the mixer circuit;
- and
- a current source with one terminal coupled to the power source to generate a direct current to the mixer circuit;
- a second current mirror circuit, further comprising:
- an impedance with one terminal coupled to the power source and the other terminal coupled to a second power input terminal of the mixer circuit;
- and
- a current source with one terminal coupled to the power source and the other terminal coupled to output terminal of the gain amplified circuit to generate a direct current to the mixer circuit;
- and
- a third current mirror circuit, further comprising:
- an impedance, with one terminal coupled to the other terminal of the current source of the first current mirror circuit and the other terminal coupled to ground;
- and
- a current source with one terminal coupled to the output terminal of the gain amplified circuit and the other terminal coupled to ground, the third current mirror circuit generating a direct current.
A mixer of a communication system, wherein the communication comprises an antenna, a low noise amplifier, the mixer, a local oscillator and an intermediate frequency filter and the mixer comprises a mixer circuit, a voltage auto-tracking circuit, a gain amplified circuit and a direct current voltage generating circuit, the direct current voltage generating circuit is coupled to an input terminal of a local oscillator of the mixer circuit to generate a fixed threshold voltage, the direct current voltage generating circuit comprising:
- a first PMOS, having a source coupled to the power source, and a base and a drain coupled to each other;
- a first NMOS, having a drain coupled to the drain of the first PMOS, a gate and coupled to the drain of the first NMOS, and a base and a source coupled to each other;
- a second NMOS, having a drain coupled to the source of the first NMOS, a gate coupled to the drain of the second NMOS, and a base and a source coupled to each other;
- a second PMOS, having a source coupled to the power source, a gate coupled to the gate of the first PMOS, a drain coupled to the gate of the second PMOS, and a base coupled to the drain of the second PMOS;
- a third NMOS, having a drain coupled to the drain of the second PMOS, a gate coupled to the gate of the first NMOS, a base and a source coupled to each other;
- a fourth NMOS, having a drain coupled to the source of the third NMOS, a gate coupled to the gate of the second PMOS, a source coupled to the source of the second NMOS, and a base coupled to the source to the fourth NMOS;
- a fifth NMOS, having a drain coupled to the source of the fourth NMOS, a gate coupled to a bias power source, a source couple to ground and a base coupled to the source of the fifth NMOS;
- a third PMOS, having a source coupled to the power source, a gate coupled to the drain of the second PMOS, a drain coupled to the output terminal of the direct current voltage generating circuit, and a base coupled to the drain of the third PMOS;
- and
- a sixth NMOS, having a drain coupled to the drain of the third NMOS, a gate coupled to the drain of the sixth NMOS, a source coupled to the source of the third NMOS and a base coupled to the source of the sixth NMOS.
Dependencies are inferred from the claim text.