# US 10,481,283 B2 · Configurable analog-to-digital converter and processing for photon counting

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- Number: US 10,481,283 B2
- Document ID: US10481283B2
- Status: Granted
- Kind: B2
- Application number: 16/181,386
- Filed: 2018-11-06
- Published: 2019-03-21
- Granted: 2019-11-19
- Earliest claimed: 2017-08-02
- Assignees: Texas Instruments Incorporated
- Applicants: Texas Instruments Incorporated
- Inventors: Rakul Viswanath; Nagesh Surendranath; Goli Sravana Kumar
- Web page: https://patentgrep.com/patent/US10481283B2

## CPC

- G01T 1/247: {Detector read-out circuitry (for processing gain or off-set correction H04N)}
- G01T 1/17: Circuit arrangements not adapted to a particular type of detector {(pulse-selection circuits H03K, G01R)}
- H03M 1/46: with digital/analogue converter for supplying reference values to converter
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)

## Abstract

A photon counting system includes a photon sensor, a charge-sensitive amplifier (CSA) and an analog-to-digital converter (ADC). The CSA is configured to convert photon energy detected by the photon sensor to voltage pulses. The ADC is configured to digitize the voltage pulses generated by the CSA. The ADC includes successive approximation circuitry. The successive approximation circuitry includes an N-bit digital-to-analog converter (DAC), an N-bit successive approximation register (SAR), a plurality of N-bit registers, and a multiplexer configured to selectively route outputs of the SAR and outputs of the N-bit registers to the DAC for conversion to an analog signal.

## Claims

### Claim 1

A photon counting system, comprising:
a photon sensor;
a charge sensitive amplifier (CSA) coupled to the photon sensor; and
an analog to digital converter (ADC) coupled to the CSA, the ADC comprising:
successive approximation circuitry comprising:
an N-bit digital-to-analog converter (DAC);
an N-bit successive approximation register (SAR);
a plurality of N-bit registers;
a multiplexer.

### Claim 2 (depends on 1)

The photon counting system of claim 1, wherein each of the N-bit registers is representative of an energy value corresponding to an energy bin of the photon counting system.

### Claim 3 (depends on 1)

The photon counting system of claim 1, wherein the ADC comprises a mode selection input for reception of a signal that controls whether the multiplexer routes outputs of the SAR or the N-bit registers to the DAC.

### Claim 4

An analog to digital converter (ADC), comprising:
successive approximation circuitry comprising:
an N-bit digital-to-analog converter (DAC);
an N-bit successive approximation register (SAR) coupled to the DAC;
a plurality (M) of N-bit registers coupled to a multiplexer;
wherein the multiplexer is coupled to the DAC and SAR.

### Claim 5 (depends on 4)

The ADC of claim 4, further comprising:
a mode selection input; and
control circuitry coupled to the mode selection input.