Raydium Semiconductor Corporation

Yu Kuang

Shih-Tzung Chou

Yong-Nien Rao

Chih Yuan

Zong-Lin Wu

Shih-Chin Chang

Shih Tzung Chou

Tsung-Yi Su

Tsung Lin Wu

Yong Nien Rao

A circuit and method of measuring capacitance are disclosed. The capacitance measuring circuit includes an integrator circuit, a first control circuit, a second control circuit and a processor circuit. The capacitance measuring method includes steps of: using a current source and a charging/discharging time to generate a first charge amount related to a second charge amount of a capacitor to be detected; generating a third charge amount and generating a fourth charge amount according to the first charge amount and the third charge amount; generating a fifth charge amount and generating a remaining charge amount according to the fifth charge amount and fourth charge amount; using an integrator to convert the remaining charge amount into a first voltage and generating a judging result according to whether the first voltage meets a second voltage; and calculating the judging result to obtain a capacitance variation of the capacitor to be detected.

Capacitance measuring circuit and capacitance measuring method

A touch sensing circuit includes N periodic-wave signal generation modules, an analog front-end circuit module, N mixing modules, and N integration modules. N is an integer. The N periodic-wave signal generation modules generate N first periodic-wave signals having N frequencies to N first channels of a capacitive touch panel. The analog front-end circuit module receives and demodulates the N first periodic-wave signals passing through N mutual capacitance at N intersection points of the N first channels and a second channel to output an analog front-end signal. The N mixing modules mix the analog front-end signal and N second periodic-wave signals having the N frequencies respectively into N mixed signals. The N integration modules integrate the N mixed signals to generate N output signals.

Touch sensing circuit of capacitive touch panel

A capacitance evaluation circuit includes a capacitive voltage divider, an analog-to-digital converter (ADC) and a processing module. The capacitive voltage divider includes a switch circuit, a known capacitor and a capacitor under test. The switch circuit is controlled by first and second clock signals. A voltage variation at a first terminal of the known capacitor is coupled to a first terminal of the capacitor under test based on a conduction state of the switch circuit. The ADC converts a voltage on the first terminal of the capacitor under test into a digital signal. The processing module detects a capacitance and a capacitance variation of the capacitor under test according to the digital signal from the ADC and a parameter of the ADC.

Capacitance evaluation circuit and electronic device using the same

A capacitance measurement circuit includes an operation amplifier; a reference capacitor having a first terminal coupled to a first input terminal of the operation amplifier and a second terminal selectively coupled to a first or second reference voltage; a sensor capacitor having a first terminal coupled to a second input terminal of the operation amplifier and a second terminal selectively coupled to the first or second reference voltage; an approximation unit having an output terminal and an input terminal coupled to an output terminal of the operation amplifier; a conversion unit having an output terminal and an input terminal coupled to the output terminal of the approximation unit; and a coupling capacitor having a first terminal coupled to the first or second input terminal of the operation amplifier and a second terminal coupled to the output terminal of the conversion unit.

Capacitance measurement circuit and method therefor

The present invention discloses a control device for a touch panel that comprises a plurality of X-directional sensing lines and Y-directional sensing lines. The X-directional sensing lines and Y-directional sensing lines are arranged in an interlaced manner. The control device comprises a clock generation circuit, a selection module, a driving signal generation circuit, a differential detection module, and a digital-to-analog conversion module. The selection module selects a first sensing line and a second sensing line from the X-directional sensing lines or Y-directional sensing lines. The driving signal generation circuit generates first and second driving signals to the first and second sensing lines, respectively. The digital to analog conversion module selectively outputs a first voltage to the first sensing line or outputs a second voltage to the second sensing line. The operation frequency of the touch panel can be increased using the control device of the present invention.

Control device for a touch panel

An touch input electronic device includes: a touch input device; a clock generation circuit, generating a first clock and a second clock; a touch sensing circuit, coupled to the touch input device, the touch sensing circuit operated under the first clock; a logic circuit, receiving a sensing output signal from the touch sensing circuit, the logic circuit operated under the second clock; and a conversion circuit, outputting an output voltage under control of the logic circuit, the output voltage coupled to the touch sensing circuit, the conversion circuit operated under the second clock. In response to the sensing output signal from the touch sensing circuit, the logic circuit controls the conversion circuit to adjust the output voltage to detect a capacitance variance of the touch input device.

Touch input electronic device

A touch panel includes a plurality of X-directional sensing lines and a plurality of Y-directional sensing lines. The X-directional sensing lines and the Y-directional sensing lines are arranged in a staggered manner. The control device includes a clock generation circuit, a selection module, a drive signal generation circuit, a digital to analog conversion module, first and second capacitors and a differential detection circuit. The X-directional sensing lines and Y-directional sensing lines on the touch panel operate according to a predetermined scanning sequence. According to the control device and the predetermined scanning sequence of the present invention, the sensing speed of the touch panel can be improved.

The invention discloses a touch input device and a touch sensor circuit. The touch input device includes a touch panel, a selection module and a differential detection module. The touch panel includes a plurality of capacitive nodes thereon. The selection module is electrically connected with the capacitive nodes of the touch panel. The selection module selects a first capacitive node and a second capacitive node from the capacitive nodes. The second capacitive node is close to the first capacitive node. The differential detection module, electrically connected to the selection module, is used for detecting a capacitance difference between the first capacitive node and the second capacitive node. According to the capacitance difference, the differential detection module generates a touch detection signal.

Touch input device and touch sensor circuit

A comparator includes: a wide-swing operation transconductance amplifier (OTA), having first and second differential input pairs for receiving first and second differential input signals respectively, the wide-swing OTA generating first and second intermediate output voltages in comparing the first with the second differential input signals; a current switch group; a current mirror group, wherein when an input common mode voltage of the first and the second differential input signal tends to one of a first and a second reference voltage, one of the first and the second differential input pair is turned off, and the current switch group and the current mirror group compensate a current flowing through the other of the first and the second differential input pair; and a decision circuit coupled to the wide-swing OTA, for enlarging a voltage difference between the first and the second intermediate output voltage to output a voltage comparison output signal.

Comparator

A capacitance measurement circuit and a capacitance measurement method thereof. The capacitance measurement circuit for measuring a capacitor under test includes a capacitance to time unit, a continuous time integrator and an analog to digital converter. The capacitance to time unit generates a first clock signal and a second clock signal reverse to the first clock signal according to a first charge time of the capacitor under test and a second charge time of a variable capacitor. The continuous time integrator receives the first clock signal and outputs an integral signal according to the first clock signal. When the number of clocks of the second clock signal is equal to a default value, the analog to digital converter outputs a digital signal corresponding to a capacitance difference between the capacitor under test and the variable capacitor according to the integral signal.

Capacitance measurement circuit and capacitance measurement method thereof

In an evaluation method, voltages at ends of a to-be-measured capacitor and a capacitance-adjustable circuit are switched in response to a first set of clock signals so as to adjust an integrated voltage to be a sum of the integrated voltage and a first difference voltage. Next, whether a first control event is received is judged. If not, the previous step is performed. If yes, an integration operation is performed to switch a voltage of an end of a known capacitor in order to adjust the integrated voltage to be a sum of the integrated voltage and a second difference voltage. Next, whether an integrating period ends is judged. If not, the first step is repeated. If yes, a capacitance of the to-be-measured capacitor is obtained according to the number of times that the integration operation is performed in the integrating period and a capacitance of the known capacitor.

Evaluation circuit for capacitance and method thereof

A measurement method for capacitance includes the following steps. First, a voltage on at least one end of a to-be-measured capacitor is switched in response to a first set of clock signals such that a level of an integrated voltage is adjusted from a start voltage level to an end voltage level in a first integration period, wherein a capacitance of the to-be-measured capacitor is relevant to a difference between the end voltage level and the start voltage level. Next, the level of the integrated voltage is adjusted from the end voltage level to the start voltage level in a second integration period in response to a second set of clock signals. Then, the capacitance of the to-be-measured capacitor is obtained according to the first and second integration periods and a known characteristic parameter.

Growing community of inventors

Hsinchu, Taiwan

Yu Kuang