The emitter current supplied from a transistor is maintained proportionally related by a factor k to current withdrawn from a first resistive network. This is done by applying the collector current of the transistor to a second resistive network having a current-versus-voltage characteristic proportionally related by the factor k to that of the first resistive network, comparing the potentials developed across the first and the second resistive networks in a differential amplifier to develop and to amplify an error signal, and then applying the amplified error signal to the base electrode of the transistor so as to degenerate error signal.
A differential amplifier includes differentially connected transistors, a first current mirror circuit used as an active load of the differentially connected transistors, and a second current mirror circuit connected to the common emitter side of the differentially connected transistors so as to reduce an off-set DC current that may be produced at the output terminal of the differentially connected transistors.
A current mirror circuit assembly includes a first current mirror circuit formed of an input transistor connected as a diode and a mirror transistor. The input transistor and the mirror transistor have gate terminals connected to one another and output circuits with output terminals. One of the output terminals of each of the input transistor and the mirror transistor are connected to a supply potential. A regulating transistor has an output circuit connected in series with the output circuit of the mirror transistor. A second current mirror circuit is formed of transistors with output circuits. Other transistors are controlled by the other of the output terminals of a respective one of the input transistor and the mirror transistor. One of the other transistors is fed back to the regulating transistor and the other transistors are connected to the output circuits of the transistors of the second current mirror circuit.
A transconductor tuning circuit for controlling transconductance of a transconductor. The tuning circuit includes a first MOS (Metal-Oxide Semiconductor) transistor. A source terminal of the first MOS transistor is connected to a power source. A gate terminal and a drain terminal of the first MOS transistor being connected to each other. A gate terminal and a drain terminal of a second MOS transistor being connected. A first input terminal of a first error amplifier is connected to the gate terminal of the first MOS transistor. A second input terminal of the first error amplifier is connected to the gate terminal of the second MOS transistor. The first error amplifier outputs an output signal in form of a bias signal for controlling tuning of the transconductor.
A current-distribution circuit (1) supplies a plurality of substantially equal currents (i.sub.1, i.sub.2, i.sub.3 and i.sub.4) to a permutation circuit (13), which transfers these currents to outputs (18, 19, 20 and 21) in accordance with a cyclic permutation. The currents in these outputs exhibit a ripple caused by the inequality of the currents (i.sub.1, i.sub.2, i.sub.3 and i.sub.4). A detection circuit (30) detects the ripple component of the currents (i.sub.1, i.sub.2, i.sub.3 and i.sub.4) and applies this ripple component to a associated control circuit of a block of control circuits (50). The relevant control circuit supplies a control current for correcting the relevant current (i.sub.1, i.sub.2, i.sub.3 or i.sub.4) in such way that the ripple component is substantially eliminated.
A self-balancing bridge network has first and second terminals defining a port for receiving power and has third and fourth terminals defining a port across which voltage is to be nulled. Transistors are located between each terminal of the port for receiving power and each terminal of the port across which voltage is to be nulled. A pair of these transistors are differentially degenerated, so that balancing of the bridge establishes predetermined levels of current in all the transistors. Such bridges are useful in two terminal current regulation, reference current sources, and in reference voltage sources.
