Integrating filter circuit
AssigneeKabushiki Kaisha Toshiba
InventorChikashi Nakagawara
Life of this patent
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Abstract
An integrating filter circuit having a reference potential source for supplying the integrating filter circuit with a prescribed reference potential, a transconductance circuit provided with a differential circuit, a variable current source couple to the differential circuit and output means coupled to the differential circuit for outputting an intermediate voltage of the outputs of the differential circuit, a common feedback loop with a comparison circuit coupled between the output means and the variable current source so as to stabilize the intermediate voltage in reference to a reference voltage supplied to the comparison circuit and capacitors coupled between the variable current source and the reference potential source.
Claims9
An integrating filter circuit comprising:
- a reference potential source for supplying the integrating filter circuit with a prescribed reference potential;
- a transconductance circuit provided with a differential circuit, a variable current source directly coupled to first and second outputs of the differential circuit and node means coupled to the variable current source for outputting an intermediate voltage of the differential circuit;
- a common feedback loop with a comparison circuit coupled between the node means and the variable current source so as to stabilize the intermediate voltage in reference to a reference voltage supplied to the comparison circuit;
- capacitors coupled between the variable current source and the reference potential source;
- and
- another capacitor coupled between the first and second outputs of the differential circuit.
An integrating filter circuit comprising:
- a reference potential source;
- a transconductance circuit including a differential circuit,
- a variable current source coupled to first and second outputs of the differential circuit, and
- node means coupled to the variable current source;
- a common feedback loop coupled between the node means and the variable current source,
- the common feedback loop comprising
- a comparison circuit including a pair of transistors arranged in a differential circuit configuration, each transistor including an emitter and a collector, the transistors being arranged in a common-emitter circuit configuration;
- and
- a feedback transistor including a collector and a base, and being configured as a diode, the collector of the feedback transistor being connected to the collector of one of the transistors of the pair of comparison circuit transistors, and the base of the feedback transistor being connected to the variable current source;
- and
- capacitors coupled between the variable current source and the reference potential source.
Dependencies are inferred from the claim text.