The invention relates to the field of electronic communication, and discloses a circuit for supplying a precise low-frequency clock signal, and a control method for the circuit. The circuit for supplying the precise low-frequency clock signal comprises an external precise clock and a resistance and capacitance (RC) oscillation circuit and an RC calibration circuit which are manufactured in the same chip, wherein the RC calibration circuit executes calibration according to the external precise clock and a successive approsimation register (SAR) logic and obtains a fixed RC constant; and a produced calibration code for controlling a capacitor array can adjust the capacitor array of the RC oscillation circuit in the same chip, so that the RC oscillation circuit outputs the low-frequency precision clock which is simple and effective. After the RC oscillation circuit finishes circuit calibration, the external high-frequency precise clock and the RC calibration circuit can be switched off, so that power consumption can be greatly reduced.

Circuit for supplying precise low-frequency clock signal, and control method for circuit

The invention discloses a measuring method of a RC constant of a ground capacitance. According to the invention, on the basis of a circuit structure that takes a RC constant as a ground capacitance, the RC constant is converted to a pulse width and a digital circuit is employed, so that a measuring method aiming at the RC constant as the ground capacitance is realized. The method enables the measurement of the RC constant as the ground capacitance and correction of the RC constant in the circuit to be realized. A ground capacitance circuit module enables the conversion of the RC constant and a time constant to be realized easily, thereby providing a condition for measurement and correction by employing the digital circuit. The correction of the RC constant of the digital circuit can be carried out conveniently and agilely; and the binary search algorithm enables the correction speed to be enhanced substantially. Therefore, the method can be better applied to measurement and correction of a RC constant in a circuit structure of a ground capacitance.

Measuring method of RC constant of ground capacitance

The invention relates to a portable control device and a method thereof. The control device comprises a driver, a base frequency controller and a quartz oscillator, wherein the driver comprises an oscillator and is used for generating a feedback signal; the base frequency controller is coupled to the driver and used for receiving the feedback signal and outputting a correction signal to the driver according to the feedback signal; and the quartz oscillator is coupled to the base frequency controller and used for generating an accurate output frequency to operate the base frequency controller.

Portable control device and method thereof

The invention discloses an RC (resistance capacitance) constant measuring method of differential capacitance. The method provided by the invention is based on a circuit structure of which differential capacitance is an RC constant, converts the RC constant into a pulse width, and uses a digital circuit to measure the RC constant of the differential capacitance. The method measures the RC constant of the differential capacitance and corrects the same in a circuit, and the method can be widely used in the field of measurement and correction on the RC constant of the differential capacitance better. A measuring module circuit simply implements the conversion between the RC constant and an RC out voltage value, so that the condition for measuring and correcting the RC constant through the digital circuit is provided, the digital circuit can flexibly and conveniently correct the RC constant, and the correction speed is greatly improved through a binary search algorithm.

RC constant measuring method of differential capacitance

The invention relates to a chip built-in RC time constant correction method used in an integrated circuit tuner, wherein the integrated circuit tuner comprises a receiving circuit receiving radio frequency signal, an orthogonal frequency mixer coupled in the output end of the receiving circuit, a multiphase filter, a relaxation oscillator and a digital correction module, wherein the image signal filteration function of the multiphase filter and the oscillating period of the relaxation oscillator are controlled by a chip built-in RC time constant. The correction method comprises the following steps: a clock in direct proportion to the chip built-in RC time constant is generated; the clock is input in the counter arranged inside the digital correction module; within a preset time slot, the clock cycle is counted to generate a counting value; moreover, by means of continuous approximation correction method and according to the counting value, the chip built-in RC time constant is updated.

Yingji Chen

Papers

Emendation method and apparatus for capacitance time constant of chip built-in resistance