Capacitance measurement circuit and method
A measurement method and technology for measuring circuits, which are applied in the direction of measuring electrical variables, measuring current/voltage, measuring resistance/reactance/impedance, etc., and can solve problems such as slowing down of capacitance measurement.
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
no. 1 example
[0039] figure 2 A block diagram showing a capacitance value measuring circuit according to a first embodiment of the present invention. Such as figure 2 As shown, the capacitance measurement circuit according to the embodiment of the present invention includes: a voltage detection circuit (Voltage Detection Circuit, VDC) 210, a switch controller 220, switches SW1-SW4, a storage capacitor Cs, and a programmable current source (Programmable current source, PCS). Cx represents the capacitance to be measured. The capacitance Cx to be measured does not necessarily only have a capacitance effect, but may also contain a resistance effect; even so, the measurement time of the capacitance measurement circuit according to this embodiment will not be too long.
[0040] The voltage detection circuit 210 detects the voltage V on the storage capacitor Cs det , and the detected voltage V det It is transmitted to the switch controller 220 and the back-end circuit.
[0041] The switch ...
no. 2 example
[0060] Figure 7 A block diagram showing a capacitance value measuring circuit according to a second embodiment of the present invention. Compared with the first embodiment, the capacitance measurement circuit of the second embodiment further includes an analog-to-digital converter (ADC) 710, which is used to convert the analog signal (voltage V det ) into digital data. Figure 8A to Figure 8D Shows how the ADC 710 converts.
[0061] Please refer now Figure 8A . As above, the voltage V det The state of charge is related to the capacitance under test C X the capacitance value. If adopted Figure 4 or Figure 5 The sensing method (that is, the waveform of the control signal S4 is as follows Figure 4 or Figure 5 shown). Capacitance to be measured C X The smaller the capacitance value, the voltage V det The faster the charging speed, it also represents the voltage V det with the reference line (V det =V ref ) between the more cross (cross over) points (CP1 ~ CPN...
no. 3 example
[0066] Figure 9 A block diagram showing a capacitance value measuring circuit according to a third embodiment of the present invention. Compared with the first embodiment, the capacitance value measuring circuit of the third embodiment further includes a filter amplifier (filter and amplifier) 910, which is used for the analog signal (voltage V det ) for filtering and amplification to output analog data. Figure 10 The filtering and amplifying modes of the filter amplifier 910 are shown.
[0067] Please refer now Figure 10 . If adopted Figure 4 , Figure 5 or Figure 6 The sensing method (that is, the waveform of the control signal S4 is as follows Figure 4 , Figure 5 or Figure 6 shown). Capacitance to be measured C X The smaller the capacitance value, the voltage V det The faster the charging and discharging speed, the filtered and amplified waveform f out frequency will be higher. Therefore, the waveform f out The frequency can reflect the measured cap...
PUM
Login to View More Abstract
Description
Claims
Application Information
Login to View More