Readout method, readout circuit and sensing apparatus with wide dynamic range
地域：
Hsinchu
摘要
A readout circuit that includes an amplifier circuitry, an analog-to-digital converter, a feedback circuit and a control logic is introduced. The amplifier circuitry may receive and amplify a differential signal that is obtained according to an input signal and a feedback signal to generate an amplified signal. The analog-to-digital converter is configured to convert the amplified signal to generate a n-bit digital code, wherein n is a positive integer. The feedback circuit is configured to search and generate a m-bit digital code based on a value of the n-bit digital code and convert the m-bit digital code to generate the feedback signal, wherein m is a positive integer. The control logic is coupled to the analog-to-digital converter and the feedback circuit, and configured to control the analog-to-digital converter and the feedback circuit. A multi-bit digital output of the readout circuit is generated according to the n-bit digital code and the m-bit digital code.
說(shuō)明書
In a sensor system, a detection resolution and a detectable range are two critical parameters that influence to performance the sensing system. However, there is a trade-off between the detection resolution and the detectable range. For example, a sensing system with high detection resolution would have narrow detectable range, and a sensing system with high detection range would have low detection resolution. Some sensing systems use a tunable amplifier with a moderate analog-to-digital converter (ADC) to realize a wide detectable range. However, these sensing systems can only be used for either a wide-range and low amplification gain detection or a narrow range and high amplification gain detection. Some alternative sensing systems use a high-resolution ADC, such as sigma-delta ADC, to achieve wide dynamic range detection. However, the sensing systems with high-resolution ADC suffers from low-speed data rate and complex implementation.
As demand for a sensing apparatus with a wide dynamic range and having a simple and small-in-size ADC has grown recently, it has a grown need for a more creative design methodology for sensing apparatus and a readout circuit of the sensing apparatus.
Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
權(quán)利要求
What is claimed is:1. A readout circuit, comprising:an amplifier circuitry, configured to receive and amplify a differential signal that is obtained according to an input signal and a feedback signal to generate an amplified signal; an analog-to-digital converter, coupled to the amplifier circuitry, configured to convert the amplified signal to generate a n-bit digital code, wherein n is a positive integer; a feedback circuit, configured to search and generate a m-bit digital code based on a value of the n-bit digital code and convert the m-bit digital code to generate the feedback signal, wherein m is a positive integer; and a control logic, coupled to the analog-to-digital converter and the feedback circuit, and configured to control the analog-to-digital converter and the feedback circuit, wherein the n-bit digital code is combined with the m-bit digital code to generate a multi-bit digital output of the readout circuit. 2. The readout circuit of claim 1 , whereinthe m-bit digital code comprises a most-significant-bit of the multi-bit digital output; and the n-bit digital code comprises a least-significant-bit of the multi-bit digital output. 3. The readout circuit of claim 1 , wherein the feedback circuit comprises:a digital-to-analog converter, configured to convert the m-bit digital code to generate the feedback signal. 4. The readout circuit of claim 1 , further comprising:a differential circuit, coupled to the feedback circuit, configured to calculate a difference between the input signal and the feedback signal to generate the differential signal. 5. The readout circuit of claim 4 , whereinthe digital-to-analog converter is a successive approximation resister digital-to-analog converter; and the analog-to-digital converter is a successive approximation resister analog-to-digital converter. 6. The readout circuit of claim 4 , whereinthe input signal and the feedback signal are voltage signals, and the amplifier circuitry comprises:a first resistor, coupled to the differential circuit; an amplifier, having a first input terminal and a second input terminal, wherein the first input terminal is coupled to the first resistor, and the second input terminal is coupled to a reference node; and a second resistor, coupled to the amplifier in parallel, wherein the second resistor is coupled between the first input terminal and an output terminal of the amplifier. 7. The readout circuit of claim 1 , whereinthe input signal and the feedback signal are current signals, and the amplifier circuitry comprises:an amplifier, having a first input terminal and a second input terminal, wherein the first input terminal is configured to receive the differential signal, and the second input terminal is coupled to a reference node; and a resistor, coupled to the amplifier in parallel, wherein the resistor is coupled between the first input terminal and an output terminal of the amplifier. 8. The readout circuit of claim 1 , wherein the amplifier circuitry is configured to amplify the differential signal with a fixed amplification gain to generate the amplified signal. 9. A sensing apparatus, comprising:a sensor, configured to generate an input signal; a readout circuit, coupled to the sensor to receive the input signal, configured to search and generate a multi-bit digital output based on the input signal, wherein the readout circuit comprises:an amplifier circuitry, configured to receive and amplify a differential signal that is obtained according to the input signal and a feedback signal to generate an amplified signal; an analog-to-digital converter, coupled to the amplifier circuitry, configured to convert the amplified signal to generate a n-bit digital code, wherein n is a positive integer; a feedback circuit, configured to search and generate a m-bit digital code based on a value of the n-bit digital code and convert the m-bit digital code to generate the feedback signal, wherein m is a positive integer; and a control logic, coupled to the analog-to-digital converter and the feedback circuit, and configured to control the analog-to-digital converter and the feedback circuit, wherein the n-bit digital code is combined with the m-bit digital code to generate the multi-bit digital output. 10. The sensing apparatus of claim 9 , whereinthe m-bit digital code comprises a most-significant-bit of the multi-bit digital output; and the n-bit digital code comprises a least-significant-bit of the multi-bit digital output. 11. The sensing apparatus of claim 9 , wherein the feedback circuit comprises:a digital-to-analog converter, configured to convert the m-bit digital code to generate the feedback signal. 12. The sensing apparatus of claim 9 , wherein the readout circuit further comprises:a differential circuit, coupled to the feedback circuit, configured to calculate a difference between the input signal and the feedback signal to generate the differential signal. 13. The sensing apparatus of claim 12 , whereinthe digital-to-analog converter is a successive approximation resister digital-to-analog converter; and the analog-to-digital converter is a successive approximation resister analog-to-digital converter. 14. The sensing apparatus of claim 12 , whereinthe input signal and the feedback signal are voltage signals, and the amplifier circuitry comprises:a first resistor, coupled to the differential circuit; an amplifier, having a first input terminal and a second input terminal, wherein the first input terminal is coupled to the first resistor, and the second input terminal is coupled to a reference node; and a second resistor, coupled to the amplifier in parallel, wherein the second resistor is coupled between the first input terminal and an output terminal of the amplifier. 15. The sensing apparatus of claim 9 , whereinthe input signal and the feedback signal are current signals, and the amplifier circuitry comprises:an amplifier, having a first input terminal and a second input terminal, wherein the first input terminal is configured to receive the differential signal, and the second input terminal is coupled to a reference node; and a resistor, coupled to the amplifier in parallel, wherein the resistor is coupled between the first input terminal and an output terminal of the amplifier. 16. The sensing apparatus of claim 9 , wherein the amplifier circuitry is configured to amplify the differential signal with a fixed amplification gain to generate the amplified signal. 17. A readout method, comprising:receiving and amplifying a differential signal that is obtained according to an input signal and a feedback signal to generate an amplified signal; converting the amplified signal to generate a n-bit digital code, wherein n is a positive integer; searching and generating a m-bit digital code based on a value of the n-bit digital code and converting the m-bit digital code to generate the feedback signal, wherein m is a positive integer; and combining the n-bit digital code with the m-bit digital code to generate a multi-bit digital output. 18. The readout method of claim 17 ,wherein the m-bit digital code comprises a most-significant-bit of the multi-bit digital output, and the n-bit digital code comprises a least-significant-bit of the multi-bit digital output. 19. The readout method of claim 17 , wherein the differential signal is amplified with a fixed amplification gain to generate the amplified signal. 20. The readout method of claim 17 , whereinthe input signal and the feedback signal are voltage signals or current signals.
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