Integratable DC blocking circuit
AssigneeMotorola, Inc.
InventorJoseph P. Heck
Life of this patent
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Abstract
An electronic circuit (100) includes an output (110) and a filter circuitry (104, 106 and 108) coupled across this forward transmission path is a feedback loop having an error amplifier (112) and a coupling amplifier (116). Switches (118, 120, 122, and 124) are situated around the error amplifier to form an auto zero circuit. A capacitor (114) in conjunction with the error amplifier (112) provides an integrator for the circuit (100). The auto zero circuit allows the output (110) to follow a desired DC voltage namely (VAG) independent of the offset voltage of the error amplifier (112) or the coupler amplifier (116).
Claims17
An electronic circuit having an output, comprising:
- a forward transmission path;
- feedback means coupled across the forward path;
- an error amplifier having an offset voltage;
- and
- auto-zero circuit for forcing the output to accurately follow a desired DC voltage independent of the offset voltage.
An integrated circuit with Direct Current (DC) blocking, comprising:
- at least one electronic circuit having an input and an output;
- a feedback loop comprising:
- an error amplifier having an offset voltage for comparing the DC voltage level of a signal at the output with a reference voltage, the error amplifier includes an auto-zeroing circuit for producing an error signal independent of the offset voltage;
- an integrator for integrating the error signal to produce an integrated error signal;
- and
- a coupler for coupling the integrated error signal to the input.
An integrated circuit having, comprising:
- at least one integrated electronic circuit having an input and an output;
- and
- a feedback loop coupled from the output to the input, the feedback loop comprising:
- an error amplifier with offset voltage, including an auto-zeroing circuit for correcting out the offset voltage.
A fully integrated electronic circuit, comprising:
- an input;
- an output;
- a forward transmission path coupling the input to the output;
- and
- a feedback loop configured around the forward transmission path for forcing a signal at the output to have a desired DC voltage level, the feedback loop having an auto-zeroing circuit.
A communication device, comprising:
- a receiver, having an electronic circuit, the circuit comprising:
- a forward transmission path;
- feedback means coupled across the forward path;
- an error amplifier having an offset voltage;
- and
- auto-zero circuit for forcing the output to accurately follow a desired DC voltage independent of the offset voltage.
Dependencies are inferred from the claim text.