Fingerprint sensor acquisition unit without excitation signal and BOOST chip
A technology of fingerprint collection and unit structure, which is applied in printing image collection, acquisition/sorting of fingerprints/palmprints, instruments, etc. It can solve the problems of complex peripheral circuits and increased costs, and achieve the effect of simple circuits and low cost
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[0021] figure 1 It is a structural diagram of a conventional fingerprint collection unit. exist figure 1 in, of which, figure 1 (a) is a sectional view, figure 1 (b) is a top view; M3 represents Metal 3, M2_1 and M2_2 represent the second layer of metal, there is a gap between M2_1 and M2_2, Ccal represents the capacitance formed by M3 and M2_1, and Cfb represents the capacitance formed by M3 and M2_2. The size of the plate formed by the combination of M2_1 and M2_2 cannot be smaller than the size of the M3 plate. Generally, in the case of 500dpi, the sum of the sizes of Ccal and Cfb is about 80f, the size of Ccal and Cfb is approximately or in a ratio of 2:1, 3:1, and the minimum Cfb is generally above 20f. When the signal is collected, the output ΔVout of the collected signal satisfies the following relationship:
[0022] ΔVout∝Vboost*Cf / Cfb. (1)
[0023] ∝ means proportional to
[0024] In formula (1), when Cf is packaged in a conventional package (after coating wit...
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