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US 9,543,997 B2Granted
System and method for a mixer
AssigneeInfineon Technologies AG
InventorsJohann Peter Forstner, Markus Ortner
Life of this patent
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Abstract
In accordance with an embodiment, a circuit includes a mixer having a signal input port, a local oscillator input port and an output port, a lowpass filter circuit having an input coupled to the output port of the mixer and a terminal configured to be connected to a shunt capacitor, and a difference circuit having a first input coupled to the output port of the mixer, and a second input coupled to an output of the lowpass filter. The output of the difference circuit substantially rejects a DC signal component at the output port of the mixer.
Claims20
A circuit comprising:
- a mixer comprising a signal input port, a local oscillator input port and an output port, wherein the output port of the mixer comprises a current mode output;
- a first current steering circuit and a second current steering circuit, wherein the first and second current steering circuit each comprises a first positive current source, a first negative current source, and an output, and for each of the current steering circuits:
- the first positive current source is coupled in series with the first negative current source, wherein
- the first positive current source is configured to provide a positive current based on a positive output of a mixer,
- the first negative current source is configured to provide a negative current based on a negative output of the mixer, and
- an output current at the output of each current steering circuit is a sum of the first positive current source and the first negative current source;
- a lowpass filter circuit having an input coupled to the output of the second current steering circuit and a terminal configured to be connected to a shunt capacitor;
- and
- a difference circuit having a first input coupled to the output of the first current steering circuit and a second input coupled to the output of the second current steering circuit and an output of the lowpass filter circuit, wherein an output of the difference circuit substantially rejects a DC signal component at the output port of the mixer.
6 more elements
An integrated circuit in a radar system comprising:
- a mixer, wherein an output port of the mixer comprises a current mode output;
- and
- a DC blocking circuit coupled to an output of the mixer, the DC blocking circuit comprising
- a first current steering circuit and a second current steering circuit, wherein the first and the second current steering circuit each comprises a first positive current source and a first negative current source and an output, wherein a value of the first positive current source and the first negative current source are a function of an output of the mixer,
- a terminal configured to be coupled to an off-chip shunt capacitor, and
- a difference circuit comprising a first input coupled to the terminal and an output of the first current steering circuit and a second terminal coupled to an output of the first current steering circuit;
- a low noise amplifier having an output coupled to an input of the mixer and an input coupled to a receive terminal of the integrated circuit;
- a frequency generator having an output coupled to a local oscillator port of the mixer;
- and
- a power amplifier having an input coupled to the frequency generator and an output coupled to a transmit terminal of the integrated circuit.
7 more elements
A radar system comprising:
- a low noise amplifier;
- a homodyne mixer coupled to an output of the low noise amplifier;
- and
- a DC blocking circuit coupled to an output of the homodyne mixer, the DC blocking circuit comprising
- a lowpass filter circuit having an input coupled to an output of a second current steering circuit, wherein the second current steering circuit is configured to generate an output current based on an output of the homodyne mixer, and
- a difference circuit having a first input coupled to an output of a first current steering circuit, wherein the first current steering circuit is configured to generate an output current based on the output of the homodyne mixer.
3 more elements
Dependencies are inferred from the claim text.