Trans-conductance amplification circuit, trans-conductance filter circuit, and filtering method
AssigneeFujitsu Limited
InventorKouji Okada
Life of this patent
Estimating the term…
Abstract
A trans-conductance filter circuit with an expanded cut-off frequency range is provided. The cut-off frequency of a trans-conductance filter circuit is changed by varying the current mirror ratio of a current mirror circuit. This mirror ratio is varied by changing the output current of a constant current source, or by switching among the respective action states of multiple transistors the actions of which are invoked within constant current regions. The variable cut-off frequency range can be expanded without losing the constant current attributes of the transistors.
Claims45
A trans-conductance amplification circuit comprising:
- a differential signal input unit;
- a first current mirror circuit connected to the differential signal input unit, which switches between a first current mirror ratio and a second current mirror ratio;
- and
- a second current mirror circuit connected to the differential signal input unit, which switches between the first current mirror ratio and the second current mirror ratio.
The trans-conductance amplification circuit according to claim 2, further including a switch control circuit controlling the switching between the first current mirror ratio and the second current mirror ratio.
The trans-conductance amplification circuit according to claim 3, wherein the switch control circuit includes at least one member selected from among registers, microcomputers, and memories.
A trans-conductance amplification circuit comprising:
- a differential signal input unit;
- a first current mirror circuit connected to the differential signal input unit;
- and
- a second current mirror circuit connected to the differential signal input unit, wherein
- at least one of the first current mirror circuit and the second current mirror circuit comprise a switch circuit and wherein the switch circuit switches between a first output current and a second output current.
A trans-conductance amplification circuit comprising
- a differential signal input unit;
- a first switch circuit connected to the differential signal input unit, which triggers a first transistor within a constant current region based on a first control signal;
- and
- a second switch circuit connected to the differential signal input unit, which triggers the first transistor and a second transistor within a constant current region based on a second control signal.
A trans-conductance amplification circuit comprising:
- a signal input unit;
- a current mirror circuit connected to the signal input unit, which switches between a first output current and a second output current;
- and
- a control circuit which controls the mirror circuit.
A trans-conductance amplification circuit comprising:
- a signal input unit;
- and
- a current mirror circuit connected to the signal input unit, wherein
- the current mirror circuit comprises a switch circuit which is controlled based on a first control signal or second control signal and selectively outputs a first output current or second output current based on the action of the switch circuit.
A trans-conductance filter circuit comprising:
- an amplification circuit which outputs a first output current by triggering a first transistor within a constant current region based on a first control signal and which outputs a second output current by triggering the first transistor and a second transistor within a constant current region based on a second control signal;
- and
- a cut-off frequency generation circuit connected to the amplification circuit and which generates a cut-off frequency for an input signal based on the first output current and the second output current.
A filtering method comprising:
- receiving an input signal;
- designating a first current mirror ratio or a second current mirror ratio based on a control signal;
- and
- filtering the input signal based on a cut-off frequency proportional to an output current based on the first current mirror ratio or the second current mirror ratio.
A filtering method comprising:
- receiving an input signal;
- outputting a first output current or second output current based on a control signal;
- and
- filtering the input signal based on a cut-off frequency corresponding to the first output current or the second output current.
A filtering method comprising:
- outputting a first output current by triggering the action of a first transistor within a constant current region based on a first control signal;
- outputting a second output current by triggering the respective actions of the first transistor and a second transistor within a constant current region based on a second control signal;
- and
- determining the cut-off frequency in relation to the input signal based on the first output current or the second output current.
A filtering method comprising:
- outputting a first output current by turning ON a first switch circuit based on a first control signal or outputting a second output current by turning ON said first switch circuit and a second switch circuit based on a second control signal;
- and
- filtering an input signal based on a cut-off frequency corresponding to the first output current or the second output current.
A filtering method comprising:
- receiving an input signal;
- performing a crude adjustment of the output current by selecting a first output current or second output current based on a control signal;
- performing a fine adjustment of the output current based on the current of a variable current source;
- and
- filtering the input signal based on a cut-off frequency corresponding to the output current.
A trans-conductance amplification circuit comprising:
- a differential signal input unit;
- and
- a number n (n is a positive integer) of current mirror circuits which select the corresponding mutually different current mirror ratios.
A trans-conductance amplification circuit comprising:
- a signal input unit;
- a number n (n is a positive integer) of current mirror circuits including switch circuits for switching and outputting mutually different output currents;
- and
- a switch control circuit which controls the switch circuits.
A trans-conductance amplification circuit comprising:
- a signal input unit;
- and
- a number n (n is a positive integer) of current mirror circuits;
- wherein each of circuits has a switch circuit which is controlled based on a control signal and selectively output multiple mutually different output currents based on the actions of the switch circuits.
Dependencies are inferred from the claim text.