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US 7,023,373 B2Granted
Multi-stage ADC with shared amplifier and reference voltage selection
AssigneeInfineon Technologies AG
InventorVictor Manuel da Fonte Dias
Life of this patent
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Abstract
The invention provides a clocked analog/digital converter for successive approximation which is designed using a jointly used amplifier and a dynamic range expansion facility by means of a special design for the comparison circuit in the first converter stage. The comparison circuits in the analog/digital converter allow decisions to be made for the further signal processing previously in a preceding time period. Two respective generator circuits in successive converter stages share one amplifier. This reduces the amount of space taken up and current drawn, increases the clock rate and simplifies signal processing for signals with high levels.
Claims19
An analog/digital converter for converting an analog input signal into a digital value, comprising:
- a first converter stage comprising an input and a signal output, the first converter stage further comprising:
- a comparison circuit configured to compare a signal amplitude of a signal applied to the input of the first converter stage with amplitudes of at least two reference signal elements, and configured to output a first control signal to a control output of the first converter stage in response thereto;
- a generator circuit configured to output a signal derived from a level of the signal applied to an input thereof to an output of the generator circuit of the first converter stage;
- a second converter stage connected downstream of the first converter stage, the second converter stage comprising:
- a control input configured to receive the first control signal, the control input connected to the control output of the first converter stage;
- a signal input connected to the signal output of the first converter stage;
- a signal output;
- a comparison circuit configured to compare a signal amplitude for an input signal applied to the input of the second converter stage with amplitudes of two reference signals, and configured to output a second control signal to a control output of the second converter stage, wherein the amplitudes of the two reference signals in the second converter stage are determined by the first control signal at the control input;
- and
- a generator circuit configured to output an output signal derived from a level of the input signal at the input and from the first control signal at the control input to an output of the generator circuit of the second converter stage;
- an evaluation circuit connected to the control outputs of the first and second converter stages, respectively, and configured to ascertain a digital value from the first and second control signals;
- and
- an amplification device comprising an input coupled via a first switching device in a first switching state to the output of the generator circuit in the first converter stage and in a second switching state to the output of the generator circuit in the second converter stage, comprising an output coupled to the signal output of the first converter stage and to the signal output of the second converter stage.
10 more elements
A method for operating an analog/digital converter, analog/digital converter comprising:
- a first converter stage comprising an input and a signal output, the first converter stage further comprising:
- a comparison circuit configured to compare a signal amplitude of a signal applied to the input of the first converter stage with amplitudes of at least two reference signal elements, and configured to output a first control signal to a control output of the first converter stage in response thereto;
- a generator circuit configured to output a signal derived from a level of the signal applied to an input thereof to an output of the generator circuit of the first converter stage;
- a second converter stage connected downstream of the first converter stage, the second converter stage comprising:
- a control input configured to receive the first control signal, the control input connected to the control output of the first converter stage;
- a signal input connected to the signal output of the first converter stage;
- a signal output;
- a comparison circuit configured to compare a signal amplitude for an input signal applied to the input of the second converter stage with amplitudes of two reference signals, and configured to output a second control signal to a control output of the second converter stage, wherein the amplitudes of the two reference signals in the second converter stage are determined by the first control signal at the control input;
- and
- a generator circuit configured to output an output signal derived from a level of the input signal at the input and from the first control signal at the control input to an output of the generator circuit of the second converter stage;
- an evaluation circuit connected to the control outputs of the first and second converter stages, respectively, and configured to ascertain a digital value from the first and second control signals;
- and
- an amplification device comprising an input coupled via a first switching device in a first switching state to the output of the generator circuit in the first converter stage and in a second switching state to the output of the generator circuit in the second converter stage, comprising an output coupled to the signal output of the first converter stage and to the signal output of the second converter stage, the method comprising:
- establishing, during a first time period, the first switching device in the second switching state;
- sampling, during the first time period, with the generator circuit in the first converter stage a signal applied to the input of the first converter stage;
- outputting, during the first time period, at the output of the generator circuit in the second converter stage a signal which is derived from a control signal at the control input and from a sampled signal, wherein the output signal is amplified by the amplification device and supplied to the signal output of the second converter stage;
- establishing, during a second time period, the first switching device in the first switching state;
- outputting, during the second time period, at the output of the generator circuit in the first converter stage a signal that is derived from the sampled signal, and this signal is amplified by the amplification device, and supplying the signal to the signal output of the first converter stage;
- and
- sampling, during the second time period, the signal applied to the input of the second converter stage with the generator circuit in the second converter stage.
17 more elements
Dependencies are inferred from the claim text.