Proximity detection method and circuit thereof
The present application provides a proximity detection method and circuit thereof. The circuit includes a detection circuit, a baseline generating circuit, and a proximity sensing circuit. The proximity sensing circuit generates a proximity signal according to a detection data generated by the detection circuit, a baseline data generated by the baseline generating circuit and a proximity threshold, and judges whether the proximity signal is valid according to the detection data, a reference data, and a valid threshold. The validity of the proximity signal may be judged according to the reference data and the valid threshold and thus avoiding false judgement caused by the influences of the ambient factors.
1. A proximity detection method, applied to an electronic device, comprising:
detecting a capacitance of an electrode for generating a detection data by a detection circuit;
generating a baseline data according to said detection data by a baseline generating circuit receiving said detection data;
generating a proximity signal according to a proximity threshold and a difference value between said detection data and said baseline data by a proximity sensing circuit receiving said detection data and said baseline data, wherein said proximity signal represents the proximity of a human body or an object to said electronic device; and
judging said proximity signal is valid or not to confirm that the proximity is occurred or not according to said detection data, a reference data, and a valid threshold by said proximity sensing circuit.
2. The proximity detection method of claim 1 , further comparing a nth value of said detection data with a (n−1)th value of said baseline data for generating said difference value, and generating said proximity signal when said difference value is greater than said proximity threshold, wherein n is a positive integer and greater than 1.
3. The proximity detection method of claim 2 , further generating said (n−1)th value of said baseline data according to a (n−1)th value of said detection data and a (n−2)th value of said baseline data, wherein n is a positive integer and greater than 2.
4. The proximity detection method of claim 1 , further comprising:
comparing a nth value of said detection data with a (n−1)th value of said baseline data for generating said difference value, and generating a nth value of said baseline data according to said nth value of said detection data and said (n−1)th value of said baseline data when said difference value is less than said proximity threshold; and
comparing a (n+1)th value of said detection data with said nth value of said baseline data for generating said difference value, and generating said proximity signal when said difference value between said (n+1)th value of said detection data and said nth value of said baseline data is greater than said proximity threshold;
where n is a positive integer and greater than 1.
5. The proximity detection method of claim 1 , further comparing a current value of said detection data with a reference value of said reference data for generating a difference value between said current value of said detection data and said reference value of said reference data, and judging said proximity signal is valid according to said valid threshold and said difference value between said current value of said detection data and said reference value of said reference data.
6. The proximity detection method of claim 1 , further resetting said reference data when said proximity signal is invalid.
7. The proximity detection method of claim 1 , further correcting said baseline data when said proximity signal is invalid.
8. The proximity detection method of claim 7 , further comprising:
setting a nth value of said detection data as a nth value of said baseline data; and
comparing a (n+1)th value of said detection data with said nth value of said baseline data for generating said difference value, and generating said proximity signal when said difference value is greater than said proximity threshold, wherein n is a positive integer and greater than 1.
9. The proximity detection method of claim 1 , further maintaining a current value of said baseline data when said proximity signal is valid.
10. The proximity detection method of claim 1 , further comparing a reference value of said reference data with a current value of said detection data when said proximity signal is valid, and setting said current value of said detection data as said reference value when said current value of said detection data is greater than said reference value.
11. The proximity detection method of claim 1 , further comparing a reference value of said reference data with a current value of said detection data when said proximity signal is valid, and maintaining said reference value when said current value of said detection data is less than said reference value.
12. A proximity detection circuit applied to an electronic device, comprising:
a detection circuit, detecting a capacitance of an electrode for generating a detection data;
a baseline generating circuit, coupled to said detection circuit, and generating a baseline data according to said detection data; and
a proximity sensing circuit, coupled to said detection circuit and said baseline generating circuit, generating a proximity signal according to a proximity threshold and a difference value between said detection data and said baseline data, wherein said proximity signal represents the proximity of a human body or an object to said electronic device; and said proximity sensing circuit judging said proximity signal is valid or not to confirm that the proximity is occurred or not according to said detection data, a reference data, and a valid threshold.
13. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit compares a nth value of said detection data with a (n−1)th value of said baseline data for generating said difference value, and generates said proximity signal when said difference value is greater than said proximity threshold, wherein n is a positive integer and greater than 1.
14. The proximity detection circuit of claim 13 , wherein said baseline generating circuit generates said (n−1)th value of said baseline data according to a (n−1)th value of said detection data and a (n−2)th value of said baseline data, wherein n is a positive integer and greater than 2.
15. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit compares a nth value of said detection data with a (n−1)th value of said baseline data for generating said difference value, and generates a nth value of said baseline data according to said nth value of said detection data and said (n−1)th value of said baseline data when said difference value is less than said proximity threshold; and said proximity sensing circuit compares a (n+1)th value of said detection data with said nth value of said baseline data for generating said difference value, and generates said proximity signal when said difference value between said (n+1)th value of said detection data and said nth value of said baseline data is greater than said proximity threshold, wherein n is a positive integer and greater than 1.
16. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit compares a current value of said detection data with a reference value of said reference data for generating a difference value between said current value of said detection data and said reference value of said reference data, and judges said proximity signal is valid according to said valid threshold and said difference value between said current value of said detection data and said reference value of said reference data.
17. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit resets said reference data when said proximity signal is invalid.
18. The proximity detection circuit of claim 12 , wherein said baseline generating circuit corrects said baseline data when said proximity signal is invalid.
19. The proximity detection circuit of claim 18 , wherein said baseline generating circuit sets a nth value of said detection data as a nth value of said baseline data; and said proximity sensing circuit compares a (n+1)th value of said detection data with said nth value of said baseline data for generating said difference value, and generates said proximity signal when said difference value is greater than said proximity threshold, wherein n is a positive integer and greater than 1.
20. The proximity detection circuit of claim 12 , wherein said baseline generating circuit maintains a current value of said baseline data when said proximity signal is valid.
21. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit compares a reference value of said reference data with a current value of said detection data when said proximity signal is valid, and sets said current value of said detection data as said reference value when said current value of said detection data is greater than said reference value.
22. The proximity detection circuit of claim 12 , wherein said proximity sensing circuit compares a reference value of said reference data with a current value of said detection data when said proximity signal is valid, and maintains said reference value when said current value of said detection data is less than said reference value.