Capacitive touch key signal measurement apparatus and measurement method therefor

Disclosed are a capacitive touch key signal measurement apparatus (100) based on a balanced or proportionally balanced capacitance bridge (10) and a measurement method therefor. The measurement apparatus (100) comprises the capacitance bridge (10), a capacitive touch key to be detected (11), a programmable capacitive compensator (12), a measurement drive circuit (15), a voltage comparator (13) and a successive approximation control circuit (14). The capacitance bridge (10) comprises four variable capacitors (CU0, CU1, CD0, CD1) which are in topologic connection according to a quadrangle. Four vertexes of the capacitance bridge (10) are marked as left, right, upper and lower vertexes (A, B, C, D). The capacitance values of the capacitors (CU0, CU1, CD0, CD1) enable the capacitance bridge (10) to be balanced or proportionally balanced. The capacitive touch key to be detected (11) is connected to the left vertex (A). The programmable capacitive compensator (12) is connected to the right vertex (B). The measurement drive circuit (15) is connected to the upper vertex (C). An input end of the voltage comparator (13) is connected to the left and right vertexes (A, B). The successive approximation control circuit (14) changes the capacitance value of the programmable capacitive compensator (12) according to an output result of the voltage comparator (13), so as to enable the capacitance bridge (10) to be balanced or proportionally balanced through many times of approximation. Compared with the prior art, the measurement apparatus and a measurement method therefor are high in measurement speed, low in noise sensitivity and simple in circuit structure.