Sensor device and mobile device including the same
A sensor device includes a sensor array including a plurality of photodiodes configured to generate current signals in response to light, an encoder configured to encode the current signals to generate a plurality of analog signals and output the plurality of analog signals sequentially, a signal processing module configured to process the analog signals, received from the encoder, to generate digital signals, and a decoder configured to decode the digital signals, received from the signal processing module, to generate a plurality of data signals corresponding to the current signals.
1. A sensor device, comprising:
a sensor array including a plurality of photodiodes configured to generate current signals in response to light;
an encoder configured to encode the current signals to generate a plurality of analog signals, and output the plurality of analog signals sequentially;
a signal processing module configured to process the analog signals, received from the encoder, to generate digital signals; and
a decoder configured to decode the digital signals, received from the signal processing module, to generate a plurality of data signals corresponding to the current signals.
2. The sensor device as claimed in claim 1 , wherein the data signals include biometric information to generate at least one of a heart rate, a blood oxygen saturation, and a blood pressure.
3. The sensor device as claimed in claim 1 , wherein the sensor array is configured to generate the current signals in response to light reflected from a blood vessel in a human body.
4. The sensor device as claimed in claim 1 , wherein:
the encoder encodes the current signals based on a predetermined orthogonal code to generate the plurality of analog signals, and
the decoder decodes the digital signals based on an inverse matrix of the orthogonal code to generate the plurality of data signals.
5. The sensor device as claimed in claim 4 , wherein the number of the plurality of photodiodes is N (where N is a positive integer of 2 or more), and the orthogonal code is defined as an N-by-N matrix.
6. The sensor device as claimed in claim 1 , wherein the encoder includes multipliers connected between the plurality of photodiodes and an input terminal of the signal processing module, and configured to multiply each of the analog signals by a predetermined coefficient.
7. The sensor device as claimed in claim 1 , wherein:
the signal processing module includes a positive input terminal and a negative input terminal, and
the encoder includes a plurality of positive switches, connected between the plurality of photodiodes and the positive input terminal, and a plurality of negative switches connected between the plurality of photodiodes and the negative input terminal.
8. The sensor device as claimed in claim 7 , wherein when the positive switch connected to one photodiode, among the plurality of photodiodes, is turned on, the negative switches connected to other photodiodes, among the plurality of photodiodes, are turned off.
9. The sensor device as claimed in claim 8 , wherein the plurality of positive switches are sequentially turned on while the plurality of photodiodes output the analog signals.
10. The sensor device as claimed in claim 1 , further comprising a light emitting unit configured to emit light, wherein:
a light emitting time, in which the light emitting unit is turned on, includes a plurality of unit times, and
the encoder multiplies at least some of the current signals by different coefficients in each of the plurality of unit times, and sums corresponding multiplication results to sequentially generate the analog signals.
11. The sensor device as claimed in claim 10 , wherein each of the plurality of unit times has a duration corresponding to a time in which the signal processing module converts each of the analog signals into a digital domain.
12. A sensor device, comprising:
a plurality of photodiodes configured to generate current signals in response to light;
an encoder connected to the plurality of photodiodes through a plurality of analog channels, the encoder including a multiplier and an adder operating based on a predetermined orthogonal code, and configured to sequentially output a plurality of analog signals, obtained by encoding the current signals, to a single input channel;
a signal processing module including an input terminal connected to the input channel, and configured to successively output a plurality of digital signals corresponding to the analog signals, to an output terminal;
a decoder connected to the output terminal and configured to output a plurality of data signals, obtained by decoding the digital signals according to an inverse matrix of an orthogonal matrix corresponding to the orthogonal code, to a plurality of digital channels; and
a processor configured to generate information corresponding to the current signals using the data signals.
13. The sensor device as claimed in claim 12 , wherein the encoder multiplies the current signals by encoding coefficients determined from the orthogonal code, and sums corresponding multiplication results to generate the analog signals.
14. The sensor device as claimed in claim 13 , wherein each of the encoding coefficients is not zero.
15. The sensor device as claimed in claim 14 , wherein, among the encoding coefficients for a respective current signal, one of the encoding coefficients is 1 and others of the encoding coefficients are −1.
16. The sensor device as claimed in claim 13 , wherein the decoder multiplies the digital signals by decoding coefficients determined from the orthogonal code, and sums corresponding multiplication results to generate the data signals.
17. The sensor device as claimed in claim 16 , wherein an absolute value of each of the decoding coefficients is smaller than an absolute value of each of the encoding coefficients.
18. The sensor device as claimed in claim 12 , wherein the encoder includes a multiplier, connected to each of the analog channels, and an adder connected to the input channel.
19. The sensor device as claimed in claim 12 , wherein the decoder includes an adder, a subtractor, and an accumulator connected to each of the digital channels.
20. A mobile device, comprising:
a substrate;
a plurality of photodiodes mounted on a first surface of the substrate and configured to generate current signals in response to light incident from an object;
a signal processing device mounted on the first surface or a second surface, facing the first surface, of the substrate and configured to convert the current signals into a plurality of data signals; and
a processor configured to obtain biometric information using the data signals,
wherein the signal processing device is configured to convert a plurality of analog signals, generated using the current signals received through a plurality of input channels, into a plurality of digital signals sequentially, and generate the data signals using the digital signals.