Precision current-source arrangement
AssigneeU.S. Philips Corporation
InventorRudy J. van de Plassche
Life of this patent
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Abstract
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.
Claims13
A precision current-source arrangement for generating a plurality of currents whose values are proportioned accurately relative to each other, which arrangement comprises
- a current-distribution circuit for generating a plurality of currents of substantially equal values, and
- a permutation circuit for transferring the currents from the current-distribution circuit to the outputs of the permutation circuit in accordance with a cyclic permutation, so that the currents available on said outputs have average values which are proportioned accurately relative to each other and exhibit a ripple whose components depend on the difference of the currents from the current-distribution circuit;
- characterized in that the arrangement also comprises
- a detection circuit for, in synchronism with the appearance of the currents from the current-distribution circuit on at least one of the outputs of the permutation circuit, detecting the deviation in value of said currents relative to a reference current, and in synchronism therewith, generating a plurality of output signals, and
- control circuits for at least some of the output signals of the detection circuit, said control circuits controlling the relevant currents from the current-distribution circuit so as to minimize said deviation.
Dependencies are inferred from the claim text.