Circuit and method of series biasing a single-ended mixer
First Claim
1. A mixer circuit, comprising:
- a first transistor having a gate, a drain and a source, said source being coupled for receiving an RF signal, said gate being coupled to a first power supply conductor;
a second transistor having a gate, a drain and a source, said gate being coupled to said drain of said first transistors said gate being further coupled for receiving an LO signal, said source being coupled to said first power supply conductor, said drain providing an IF output signal; and
circuit means coupled between said source of said second transistor and said drain of said first transistor for providing a DC signal path between said source of said second transistor and said drain of said first transistor to allow said first and second transistors to share operating current.
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Accused Products
Abstract
A mixer circuit (10) combines a buffered RF signal with the LO signal at the gate of a mixing transistor (20) for providing sum and difference product terms as the IF output signal. An inductor (46) provides a DC signal path between the source of the mixing transistor and the drain of the buffering transistor (14) to share the same operating current and thereby reduce power consumption in the mixer. The DC path inductor provides a high impedance to block the RF signal and LO signal. A bias circuit (26, 28) sets the bias point at the gate of the mixing transistor to a mid-point value between VDD and ground potential. In disable mode, the bias point of the mixing transistor is sufficiently low that the LO signal does not have sufficient power to turn on buffering and mixing transistors that could generate mixing products at the IF output.
75 Citations
19 Claims
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1. A mixer circuit, comprising:
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a first transistor having a gate, a drain and a source, said source being coupled for receiving an RF signal, said gate being coupled to a first power supply conductor; a second transistor having a gate, a drain and a source, said gate being coupled to said drain of said first transistors said gate being further coupled for receiving an LO signal, said source being coupled to said first power supply conductor, said drain providing an IF output signal; and circuit means coupled between said source of said second transistor and said drain of said first transistor for providing a DC signal path between said source of said second transistor and said drain of said first transistor to allow said first and second transistors to share operating current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of mixing an RF signal with an LO signal, comprising the steps of:
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buffering the RF signal through a first transistor for providing a buffered RF signal; mixing said buffered RF signal with the LO signal in a second transistor for providing an IF output signal; and providing a DC signal path between a conduction path of said first transistor and a conduction path of said second transistor to allow said first and second transistors to share operating current. - View Dependent Claims (11)
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12. A mixer circuit, comprising:
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a first transistor having a gate, a drain and a source, said source being coupled for receiving an RF signal, said gate being coupled to a first power supply conductor; a second transistor having a gate, a drain and a source, said gate being coupled to said drain of said first transistor, said gate being further coupled for receiving an LO signal, said source being coupled to said first power supply conductor, said drain providing an IF output signal; and a first inductor coupled between said source of said second transistor and said drain of said first transistor for providing a DC signal path between said source of said second transistor and said drain of said first transistor to allow said first and second transistors to share operating current. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification