Device for dc offset cancellation
AssigneeMuChip Co., Ltd
InventorsYong-Hsiang Hsieh, Wen-Kai Li, David Chen
Life of this patent
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Abstract
A DC offset cancellation device is provided, including a baseband circuit, a common mode feedback (CMFB) circuit, a low-pass filter (LPF), and an amplifier. The CMFB circuit is used to set a specific common mode DC voltage in a differential circuit; thus, the CMFB circuit can be used for detecting the common mode voltage of a differential circuit, and force the voltage to a specific value by using a feedback control. Because the size of a typical CMFB circuit is much smaller than the size of an LPF, the final size of the one-LPF device is smaller than the conventional design using two LPFs.
Claims4
A device for DC offset cancellation, comprising:
- a baseband circuit, having a positive input port, a negative input port, a positive output port and a negative output port;
- a common mode feedback (CMFB) circuit, having said positive and negative output ports of said baseband circuit and a common mode voltage (VCM) as inputs, and an output connected to said baseband circuit;
- a low-pass filter (LPF), having an input connected to said positive output port of said baseband circuit and an output;
- and
- an amplifier, having a positive input port connected to said output of said LPF, a negative input port connected to said VCM, a negative output port connected to said positive input port of said baseband and a positive output port connected to said input negative port of said baseband circuit.
A device for DC offset cancellation, comprising:
- a baseband circuit, having a positive input port, a negative input port, a positive output port and a negative output port;
- a common mode feedback (CMFB) circuit, having said positive and negative output ports of said baseband circuit and a common mode voltage (VCM) as inputs, and an output connected to said baseband circuit;
- a low-pass filter (LPF), having an input connected to said negative output port of said baseband circuit and an output;
- an amplifier, having a positive input port connected to said output port of said LPF, a negative input port connected to said VCM, a negative output port connected to said negative input port of said baseband circuit, and a positive output port connected to said positive input port of said baseband circuit.
A device for DC offset cancellation, comprising:
- a baseband circuit, having a positive input port, a negative input port, a positive output port and a negative output port;
- a common mode feedback (CMFB) circuit, having said positive and negative output ports of said baseband circuit and a common mode voltage (VCM) as inputs, and an output connected to said baseband circuit;
- a low-pass filter (LPF), having an input connected to said negative output port of said baseband circuit and an output;
- and
- an amplifier, having a positive input port connected to said VCM, a negative input port connected to said output of said LPF, a negative output port connected to said positive input port of said baseband and a positive output port connected to said input negative port of said baseband circuit.
A device for DC offset cancellation, comprising:
- a baseband circuit, having a positive input port, a negative input port, a positive output port and a negative output port;
- a common mode feedback (CMFB) circuit, having said positive and negative output ports of said baseband circuit and a common mode voltage (VCM) as inputs, and an output connected to said baseband circuit;
- a low-pass filter (LPF), having an input connected to said positive output port of said baseband circuit and an output;
- and
- an amplifier, having a positive input port connected to said VCM, a negative input port connected to said output port of said LPF, a negative output port connected to said negative input port of said baseband circuit, and a positive output port connected to said positive input port of said baseband circuit.
Dependencies are inferred from the claim text.