# US 7,612,700 B2 · Pipeline type A/D converter apparatus provided with precharge circuit for precharging sampling capacitor

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- Number: US 7,612,700 B2
- Document ID: US7612700B2
- Status: Granted
- Kind: B2
- Application number: 12/139,754
- Filed: 2008-06-16
- Published: 2009-06-11
- Granted: 2009-11-03
- Earliest claimed: 2007-12-10
- Assignees: Semiconductor Technology Academic Research Center
- Inventors: Shoji Kawahito; Kazutaka Honda; Yasuhide Shimizu; Kuniyuki Tani; Akira Kurauchi; Koji Sushihara
- Web page: https://patentgrep.com/patent/US7612700B2

## CPC

- H03M 1/002: {Provisions or arrangements for saving power, e.g. by allowing a sleep mode, using lower supply voltage for downstream stages, using multiple clock domains or by selectively turning on stages when needed}
- H03M 1/0695: {using less than the maximum number of output states per stage or step, e.g. 1.5 per stage or less than 1.5 bit per stage type}
- H03M 1/164: {the steps being performed sequentially in series-connected stages (H03M1/161 takes precedence)}
- H03M 1/361: {having a separate comparator and reference value for each quantisation level, i.e. full flash converter type}
- H03M 1/442: {using switched capacitors}
- 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

In a pipeline type A/D converter apparatus including A/D converter circuit parts connected in cascade with each other and A/D converting a sample hold signal in a pipeline form, each A/D converter circuit part includes a pre-A/D converter circuit for A/D converting an input signal into a digital signal, and a multiplying D/A converter circuit for D/A converting the digital signal into an analog control signal, and D/A converting the input signal by sampling, holding and amplifying the input signal using a sampling capacitor based on the analog control signal. A precharge circuit precharges a sampling capacitor before sampling so as to attain a predetermined output value in accordance with a digital input to output characteristic substantially adapted to an input to output characteristic of each A/D converter circuit part that presents an output signal corresponding to the input signal to each A/D converter circuit part.

## Claims

### Claim 1

A pipeline type A/D converter apparatus comprising:
a sample holding circuit for sampling and holding an analog input signal, and outputting a sample hold signal; and
an A/D converter device including a plurality of A/D converter circuit parts connected in cascade with each other, the A/D converter device A/D converting the sample hold signal in a pipeline form,
wherein each of the A/D converter circuit parts comprises:
a pre-A/D converter circuit including a plurality of comparators, the pre-A/D converter circuit A/D converting the input signal into a digital signal; and
a multiplying D/A converter circuit for D/A converting the digital signal from the pre-A/D converter circuit into an analog control signal, and D/A converting the input signal by sampling, holding and amplifying the input signal using a sampling capacitor based on the analog control signal, and
wherein the pipeline type A/D converter apparatus comprises a precharge circuit for precharges the sampling capacitor before sampling so as to attain a predetermined output value in accordance with a digital input to output characteristic substantially adapted to an input to output characteristic of each of the A/D converter circuit part that presents an output signal corresponding to the input signal to each of the A/D converter circuit parts.

### Claim 2 (depends on 1)

The pipeline type A/D converter apparatus as claimed in claim 1,
wherein the pre-A/D converter circuit of each of the A/D converter circuit parts comprises:
six comparators having threshold values different from each other, each comparator comparing the input signal with the threshold value and outputting a comparison result signal; and
a logic circuit for outputting a three-value output signal based on each of the comparison result signals from the six comparators.

### Claim 3 (depends on 2)

The pipeline type A/D converter apparatus as claimed in claim 2,
wherein the comparators have threshold values of −3Vr/4, −Vr/2, −Vr/4, +Vr/4, +Vr/2 and +3Vr/4, respectively, where Vr denotes an A/D conversion reference value of each of the A/D converter circuit parts, and
wherein the logic circuit outputs an output signal having three values of −Vr, 0 and +Vr based on the comparison result signals from the six comparators.

### Claim 4 (depends on 1)

The pipeline type A/D converter apparatus as claimed in claim 1,
wherein the pre-A/D converter circuit of each of the A/D converter circuit parts comprises:
fourteen comparators having threshold values different from each other, each comparator comparing the input signal with the threshold value and outputting a comparison result signal; and
a logic circuit for outputting a three-value output signal based on each of the comparison result signals from the fourteen comparators.

### Claim 5 (depends on 4)

The pipeline type A/D converter apparatus as claimed in claim 4,
wherein the comparators have threshold values of −7Vr/8, −3Vr/4, −5Vr/8, −Vr/2, −3Vr/8, −Vr/4, −Vr/8, +Vr/8, +Vr/4, +3Vr/8, +Vr/2, +5Vr/8, +3Vr/4 and +7Vr/8, respectively, where Vr denotes an A/D conversion reference value of each of the A/D converter circuit parts, and
wherein the logic circuit outputs an output signal having three values of −Vr, 0 and +Vr based on the comparison result signals from the fourteen comparators.

### Claim 6 (depends on 1)

The pipeline type A/D converter apparatus as claimed in claim 1,
wherein each of the A/D converter circuit parts comprises:
the pre-A/D converter circuit; and
first and second multiplying D/A converter circuits each having a configuration of the multiplying D/A converter circuit, and
wherein the pipeline type A/D converter apparatus further comprises a controller for controlling the plurality of A/D converter circuit parts connected in cascade with each other so as to control the first multiplying D/A converter circuit of each of A/D converter circuit parts of odd-number stages to execute processing of precharging, sampling and holding, so as to control the second multiplying D/A converter circuit of each of the A/D converter circuit parts of the odd-number stages to execute amplification processing, so as to control the first multiplying D/A converter circuit of each of A/D converter circuit parts of even-number stages to execute amplification processing, and so as to control the second multiplying D/A converter circuit of each of the A/D converter circuit parts of the even-number stages to execute processing of precharging, sampling and holding.

### Claim 7 (depends on 6)

The pipeline type A/D converter apparatus as claimed in claim 6,
wherein, in each of the A/D converter circuit parts, one amplifier is shared by an amplifier for performing amplification processing by the first multiplying D/A converter circuit and an amplifier for performing amplification processing by the second multiplying D/A converter circuit.

### Claim 8 (depends on 1)

The pipeline type A/D converter apparatus as claimed in claim 1,
wherein the A/D converter device comprises:
a first pipeline A/D converter circuit group including a plurality of A/D converter circuit parts connected in cascade with each other; and
a second pipeline A/D converter circuit group including a plurality of A/D converter circuit parts connected in cascade with each other, and
wherein the A/D converter device A/D converts the sample hold signals of two systems using the first and second pipeline A/D converter circuit groups in a pipeline form.