US 3,987,392 AGranted

Luminescent voltage indicator circuit

AssigneeRobert Bosch GmbH

InventorsAdolf Kugelmann, Helmut Keller

Life of this patent

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Abstract

A plurality of luminescent elements, such as light-emitting diodes, incandescent lamps or the like, are located adjacent each other, each connected to the output of a difference amplifier. The respective inputs of the difference amplifier are connected, on the one hand, to a voltage divider to have different reference voltages applied thereto and, on the other, in common to the input voltage to be sampled so that, as the voltage changes between the amplification ranges of the difference amplifiers, the output therefrom will change in accordance with input voltage so that the brightness of the respectively connected luminescent elements will also change, thus providing gradual increase in brightness of any individual element as the voltage changes. The difference amplifiers may be differentially connected operational amplifiers.

Claims20

Dependent claims

a plurality of respective difference amplifiers arranged in a chain (V.sub.1 . . . V.sub.n), each associated with a respective luminescent element (L), each difference amplifier having a reference input and a test voltage input and providing an output which is an analog of the voltage difference between the inputs;
a plurality of serially connected reference resistors (R.sub.2.1 . . . R.sub.2.n) connected across a source of supply voltage (U.sub.v);
one input of the respective difference amplifiers (V.sub.1 . . . V.sub.n) being connected, in an ascending chain, to respective adjacent junctions of the serially connected reference resistors (R.sub.2.1 . . . R.sub.2.n) to apply increasing voltages to said respective inputs of the respect difference amplifiers (V.sub.1 . . . V.sub.n), the test voltage inputs of all the difference amplifiers (V.sub.1 . . . V.sub.n) being all connected to the input test voltage (U.sub.E);
and wherein the output of any difference amplifier (V.sub.1) is connected to a respective one terminal of the associated respective luminescent element (L), the other terminal of the respective luminescent element (L) being connected to the output of the next adjacent difference amplifier (V.sub.2) in the chain, so that current flow through, and hence brightness of illumination of any luminescent element (L) is dependent on the current flow through, and hence brightness of an adjacent luminescent element to energize the respective luminescent elements (L) by the difference in outputs of adjacent differential amplifiers (V.sub.1, V.sub.2 . . . V.sub.n) and to effect gradual transition of energization of the output from a difference amplifier to another, and hence of brightness of one luminescent element to an adjacent one upon change of test voltage from a level corresponding to the voltage level of the voltage connected to a difference amplifier to the voltage level of the difference amplifier connected to the adjacent luminescent element.

1 more element

Luminescent voltage indicator system having a plurality of adjacently located luminescent elements (L) arranged to indicate, by their respective location and specific illumination, the value of an input voltage (U.sub.E) to be tested, and wherein the respective luminescent elements are unidirectionally conductive, comprising a plurality of respective difference amplifiers arranged in a chain (V.sub.1 . . . V.sub.n), each associated with a respective luminescent element (L), each difference amplifier having a reference input and a test voltage input and providing an output which is an analog of the voltage difference between said inputs;

a plurality of serially connected reference resistors arranged in two groups (R.sub.2.1 . . . R.sub.2.n ;
R.sub.3.1 . . . R.sub.3.n) connected across a source of supply voltage (U.sub.V);
the outputs of any differential amplifier (V.sub.1) being connected to a pair of luminescent elements, connected in parallel, and with opposite polarity, the parallel connection of the oppositely polarized luminescent element pair having one terminal connected to the output terminal of said difference amplifier and the other terminal of the parallel connected pair being connected to the output of the next adjacent difference amplifier (V.sub.2) in the chain, so that current flow, and hence brightness of illumination of any luminescent element is dependent on the current flow through and hence brightness of illumination of an adjacent luminescent element of an adjacent pair;
a threshold switch (K) having a threshold reference voltage (U.sub.s) applied thereto as well as said test voltage (U.sub.E), and transfer switch means (S.sub.1 -S.sub.4) selectively connecting either the reference inputs or the test voltage inputs of the respective difference amplifiers to respective adjacent junctions of the serially connected reference resistors of one group, or the other (R.sub.2.1 . . . R.sub.2.n ;
R.sub.3.1 . . . R.sub.3.n) and the test voltage input and reference input, selectively, of all the difference amplifiers to the input test voltage, the output of the respective difference amplifiers changing in polarity in dependence on the switch position of the transfer switch means, and hence on the respective connection of the test voltage input and the reference input of the difference amplifiers to, selectively, the reference resistors, or the input voltage;
change-over of said threshold switch being effected when the test voltage (U.sub.E) passes the threshold determined by the threshold voltage (U.sub.s) and causes transfer of illumination from the luminescent element, of a pair connected to the output of the respective differential amplifiers to the other, reversely polarized element of the pair.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 05/480,399Filed 18 Jun 1974
Priority: DT 233166022 Jun 1973
Granted: 19 Oct 1976
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G01R 19/16595
To indicate that the value is within or outside a predetermined range of values: with multi level indication
G01R 13/405
For discontinuous display, i.e. display of discrete values: using a plurality of active, i.e. light emitting, e.g. electro-luminescent elements,…
H03M 1/361
Simultaneously only, i.e. parallel type: having a separate comparator and reference value for each quantisation level, i.e. full flash converter type
G01R
Measuring electric variables