Capacitance measuring circuit and measuring method

A measurement circuit, capacitance measurement technology, applied in capacitance measurement, measurement of electrical variables, measurement of resistance/reactance/impedance, etc., can solve the problem that the capacitance measurement scheme cannot meet the higher linearity.

CN112505427AActive Publication Date: 2021-03-16MR SEMICON
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2021-03-16

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Abstract

The invention provides a capacitance measuring circuit and a measuring method. The capacitance measuring circuit comprises a first measuring circuit, a second measuring circuit and a clamping circuit,and the first measuring circuit and the second measuring circuit comprise the same capacitor to be measured; the first measuring circuit is used for determining the first electric quantity of the capacitor to be measured according to the first clock signal in the measuring period; the second measurement circuit is used for determining a second electric quantity of the capacitor to be measured according to a second clock signal in the measurement period; and the clamping circuit is connected with the second measuring circuit and is used for controlling the second measuring circuit to count thesecond electric quantity of the capacitor to be measured when the voltage at the two ends of the clamping circuit meets the first control condition. Through the control of the clamping circuit, the electric quantity transferred by the capacitor to be measured from other circuits is more fixed, a more accurate capacitance measurement value can be obtained, and the measurement linearity is improved.
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Description

technical field

[0001] The invention relates to the technical field of capacitance measurement, in particular to a capacitance measurement circuit and a measurement method. Background technique

[0002] With the advancement of semiconductor technology, touch capacitance has been widely used. In order to adapt the touch capacitor to various application environments, it is very important to improve the reliability of the touch capacitor, and to improve the reliability of the capacitor requires accurate measurement of the capacitance value of the capacitor.

[0003] The basic working principle of measuring capacitance is to charge and discharge the capacitance to be measured by injecting current through the switch, and then deduce the capacitance value of the capacitance based on the statistics of the injected power. When the injected electricity and the capacitance value are closer to a linear relationship (that is, the capacitance measurement linearity is high), the measured...

Examples

Embodiment Construction

[0041] Embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but should not be used to limit the scope of the present invention.

[0042] An embodiment of the present invention provides a capacitance measuring circuit, the capacitance measuring circuit is used to measure the electric quantity of the capacitance to be measured during the charging and discharging process of the capacitance to be measured within one clock cycle, and determine the capacitance value based on the calculation formula according to the electric quantity. figure 1 A schematic diagram showing the structure of the capacitance measurement circuit, see figure 1 , the capacitance measurement circuit includes a first measurement circuit 11, a second measurement circuit 12 and a clamping circuit 13, wherein:

[0043] Both the first measurement circuit 11 and...