Digital-analogue converter for multi-threshold counters with partitioning of the bits between resistor ladder and comparator

Patent metadata

Field	Value
Publication number	US-10324201-B2
Application number	US-201615263522-A
Country	US
Kind code	B2
Filing date	Sep 13, 2016
Priority date	Sep 28, 2015
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

An X-ray detector includes an N-channel digital-analogue converter controllable with K+L bits. In an embodiment, the digital-analogue converter includes a first voltage source to provide a plurality of first voltage values at tapping points; and a switch unit with N switch matrices, 2 K inputs of the switch matrices being electrically conductively connected to 2 K tapping points of the first voltage source. The digital-analogue converter also includes a second voltage source including N subunits. The X-ray detector further includes a discriminator unit including N comparators, at least one input of the comparators being electrically conductively connected to the associated output of the switch matrix and/or to the associated output of the subunit, so that the associated first voltage value and the associated second voltage value are associable with each comparator. A signal of an output of a pre-amplifier, and the associated first and second voltage values are comparable in the comparator.

First claim

What is claimed is:

1. An X-ray detector comprising:
an N-channel digital-analogue converter controllable with K+L bits, including
a first voltage source to provide a plurality of first voltage values at tapping points, the first voltage values being equidistant and providable in a monotonic sequence;
a switch unit with N switch matrices, wherein 2 K inputs of the N switch matrices are electrically conductively connected to 2 K tapping points of monotonically sequential first voltage values of the first voltage source, a tapping point of the first voltage source of the N switch matrices being selectable with K bits, wherein the N switch matrices have a selected first voltage value at an output;
a second voltage source including N subunits, wherein a second voltage value is selectable with L bits; and
a discriminator unit including N comparators, at least one input of the N comparators being electrically conductively connected to an associated output of at least one of the N switch matrices and the associated output of the subunit, so that the associated first voltage value and the associated second voltage value are associable with each comparator, a signal of an output of a pre-amplifier, the associated first voltage value and the associated second voltage value being comparable in the comparator.

2. The X-ray detector of claim 1 , wherein the signal of the output of the pre-amplifier is comparable in the comparator with the sum of the first voltage value and the second voltage value.

3. The X-ray detector of claim 1 , wherein the difference between the signal of the output of the pre-amplifier and the second voltage value is comparable in the comparator with the first voltage value.

4. The X-ray detector of claim 1 , wherein on changing the switching behavior of the comparator by the second voltage value, the signal of the output of the pre-amplifier and the first voltage value are comparable in the comparator.

5. The X-ray detector of claim 1 , wherein the second voltage source is included by the discriminator unit.

6. The X-ray detector of claim 1 , wherein the first voltage source comprises a resistor chain with a plurality of equal-valued, serially arranged resistors, and wherein the tapping points are providable before or after a resistor or between adjacent resistors.

7. The X-ray detector of claim 1 , wherein the first voltage source is connected to a settable input voltage VDAC.

8. The X-ray detector of claim 1 , wherein a plurality of tapping points is electrically conductively connected to the inputs of a plurality of switch matrices.

9. The X-ray detector of claim 1 , wherein the switch matrices are configured as multiplexers.

10. The X-ray detector of claim 6 , wherein the first voltage source has a zero point regulating circuit for setting a zero point.

11. The X-ray detector of claim 10 , wherein the zero point regulating circuit comprises a first binary weighted resistance before the resistor chain and a second binary weighted resistance after the resistor chain.

12. The X-ray detector of claim 1 , wherein the second voltage source is settable.

13. The X-ray detector of claim 1 , wherein the second voltage source provides L different second voltage values, wherein the L different second voltage values make a whole number multiple of a ½ L -share of the difference between adjacent tapping points of the first voltage source.

14. The X-ray detector of claim 1 , wherein the comparators are configured as comparators with hysteresis.

15. The X-ray detector of claim 14 , wherein the hysteresis is activatable or deactivatable by way of an additional bit.

16. A medical device comprising:
the X-ray detector of claim 1 .

17. The X-ray detector of claim 1 , wherein the first voltage source has a zero point regulating circuit for setting a zero point.

18. The X-ray detector of claim 17 , wherein the zero point regulating circuit comprises a first binary weighted resistance before the resistor chain and a second binary weighted resistance after the resistor chain.

19. A medical device comprising:
the X-ray detector of claim 2 .

20. A medical device comprising:
the X-ray detector of claim 3 .

21. A medical device comprising:
the X-ray detector of claim 4 .

Assignees

• Siemens Healthcare Gmbh

Inventors

• Groepl Martin
• Goederer Edgar
• Suttorp Thomas

Classifications

• H03M1/662 Primary

  Multiplexed conversion systems · CPC title

• H03M1/808

  using resistors · CPC title

• H03M1/68

  with conversions of different sensitivity, i.e. one conversion relating to the more significant digital bits and another conversion to the less significant bits · CPC title

• G01T1/247 Primary

  Detector read-out circuitry (for processing gain or off-set correction H04N) · CPC title

• H03M1/785

  using resistors, i.e. R-2R ladders · CPC title