Fat measurement circuit and body fat scale

Abstract

The invention provides a fat measurement circuit and a body fat scale. In terms of a resistance selection circuit, a first test resistor Rt, a second test resistor Rt' and a measurement electrode are sequentially connected in series to form a serial-connection circuit; alternating-current voltage output by a reverse-phase alternating-current amplifying circuit is added to the two ends of the serial-connection circuit; a voltage sampling circuit sequentially collects voltage at the two ends of the measurement electrode, voltage at the two ends of the second test resistor Rt', voltage at the two ends of the first test resistor Rt and voltage at the two ends of the second test resistor Rt'; the value of resistance Rb of a human body can be obtained through voltage equations of three times of measurement. In order to rectify equivalent deviation brought by resistance errors and amplifier errors, the mode of introducing external resistors is adopted to indirectly calculate equivalent deviation of the test resistors, after a calculation result is obtained, the result is stored in a storage of the fat measurement circuit, in actual measurement, the equivalent deviation is put into a calculation equation of the resistance Rb of the human body, and influences produced by equivalent deviation can be eliminated and an accurate measurement value of the resistance Rb of the human body is obtained.

Description

technical field [0001] The invention relates to the technical field of health management, in particular to a fat measuring circuit and a body fat scale. Background technique [0002] With the improvement of living standards, the public pays more and more attention to physical conditions, and the desire to know the physical parameters such as body weight and body fat percentage is becoming more and more urgent. Body fat percentage refers to the ratio of body fat to body weight. Excessive body fat percentage can easily lead to chronic diseases such as high blood pressure, heart disease, diabetes and cancer. If accurate body fat percentage can be obtained, it can be used as a basis for targeted Sexual personal health management. Therefore, it is the current development trend of intelligent human body scales to expand the ordinary human body scales that only have the function of weighing to also have the function of measuring body fat. [0003] The measuring instrument with fa...

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Problems solved by technology

[0009] However, since the fat measuring circuit in the prior art uses an idealized model when measuring the impedance Z of the human body, that is, the linear error of the resistance and the amplifier is not considered, which causes a large error between the measured impedance Z of the human body and the real value. In turn, the fat rate calculated based on the body impedance Z is also seriously distorted, and the reference is poor

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