US 9,813,816 B2
Audio plug detection structure in audio jack corresponding to audio plug and method thereof
Tsung-Peng Chuang, Jhubei (TW)
Assigned to REALTEK SEMICONDUCTOR CORP., Hsinchu (TW)
Filed by REALTEK SEMICONDUCTOR CORP., Hsinchu (TW)
Filed on Apr. 2, 2015, as Appl. No. 14/677,643.
Claims priority of application No. 104102502 A (TW), filed on Jan. 26, 2015.
Prior Publication US 2016/0216303 A1, Jul. 28, 2016
Int. Cl. G01R 29/027 (2006.01); H04R 5/04 (2006.01); G01R 31/04 (2006.01)
CPC H04R 5/04 (2013.01) [G01R 31/043 (2013.01); H04R 2420/05 (2013.01)] 12 Claims
OG exemplary drawing
 
1. An audio plug detection structure, applicable to an audio jack corresponding to an audio plug, comprising:
a plurality of connection points, disposed on an inner side of the audio jack, one-to-one or multiple-to-one connected to a plurality of pole points of the audio plug when the audio plug is inserted into the audio jack, wherein each of the plurality of connection points is connected to a functional circuit or a chip pin corresponding to each of the plurality of pole points of the audio plug or a ground terminal, the plurality of connection points comprise a first connection point and a second connection point, and when the audio plug is inserted into the audio jack, the first connection point is connected to a first pole point of the plurality of pole points, and the second connection point is connected to a second pole point of the plurality of pole points, wherein the second pole point is different from the first pole point;
a time-varying signal generation circuit, connected to the first connection point and configured to generate and output a time-varying signal which flows to the second connection point of the audio jack from the first connection point of the audio jack through an inside impedance circuit formed between the first pole point and the second pole point in response to the audio plug being inserted into the audio jack; and
a comparison circuit, connected to the first connection point and receiving the time-varying signal, and comparing the time-varying signal with a reference signal;
wherein when the audio plug is inserted into the audio jack, the time-varying signal generation circuit, the first connection point, an inside impedance circuit between the first pole point and the second pole point of the audio plug, and the second connection point form a loop, and the comparison circuit outputs a determination signal to determine the audio plug is inserted into the audio jack by comparing a variation of the time-varying signal with the reference signal;
wherein the determination signal changes in response to the time-varying signal flowing to the second connection point of the audio jack from the first connection point of the audio jack through the inside impedance circuit in response to the audio plug being inserted into the audio jack.