Electronic circuit comprising complementary transconductors for filters and oscillators
AssigneeU.S. Philips Corporation
InventorsJohannes O. Voorman, Hugo Veenstra
Life of this patent
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Abstract
An electronic circuit comprises coupled transconductors (TR1 and TR2). The transconductors comprise two complementary differential pairs whose outputs are connected directly to two output terminals. Two diodes (P3, N3) are arranged in series between the common terminals of the differential pairs. The common-mode voltage of the differential pairs is available on the node between the two diodes. The common-mode voltage of the one transconductor (TR2) is used to control one of the bias current sources of the other transconductor (TR1) and, if desired, also that of the one transconductor (TR2). In this way the common-mode voltage on the output terminals of the other transconductor (TR1) is fixed.
Claims13
An electronic circuit comprising a plurality of at least a first transconductor (TR1) and a second transconductor (TR2), each having first (IA) and second (IB) input terminals for receiving a differential voltage and having first (OA) and second (OB) output terminals for supplying a differential current in response to the differential voltage, characterized in that each transconductor of the at least first transconductor (TR1) and second transconductor (TR2) comprises:
- a first differential pair (P1, P2) of transistors of a first conductivity type, having their respective first main electrodes coupled to one another in a first node (BA), having their respective second main electrodes coupled to the first output terminal (OA) and the second output terminal (OB), and having their respective control electrodes coupled to the first input terminal (IA) and the second input terminal (IB);
- a second differential pair (N1, N2) of transistors of a second conductivity type opposite to the first conductivity type of the first differential pair (P1, P2), the second differential pair having their respective first main electrodes coupled to one another in a second node (BB), having their respective second main electrodes coupled to the first output terminal (OA) and the second output terminal (OB), and having their respective control electrodes coupled to the first input terminal (IA) and the second input terminal (IB);
- a first current source (P4) coupled to the first node (BA) to supply a first bias current to the first differential pair (P1, P2);
- a second current source (N4) coupled to the second node (BB) to supply a second bias current to the second differential pair (N1, N2);
- a first diode-connected transistor (P3) of the first conductivity type and a second diode-connected transistor (N3) of the second conductivity type, which are connected in series between the first node (BA) and the second node (BB);
- and the electronic circuit further comprises:
- means (P6, P7) for controlling the first current source (P4) of at least the first transconductor (TR1) in response to a common-mode voltage of the second transconductor (TR2).
Dependencies are inferred from the claim text.