Design of a Low Power Consumption Humidity Sensor Chip

In order to solve the problem of intelligent and accurate measurement of large-area soil moisture, greenhouse and farm humidity under the condition of reducing labor force, and the problem of large power consumption of humidity sensor products on the market, this paper designed a complete low-power humidity sensor chip based on 180 nm CMOS technology. The chip uses polyimide (PI) as the humidity sensing information of the humidity sensing capacitor, and designs a capacitor-voltage interface circuit to convert the humidity information into the change of the output voltage value. A low power and small area successive approximation analog Digital converter (SAR ADC) is designed to output digital humidity information. Under the operating voltage of 1 V and the clock of 1.28 MHz, the average power consumption of the overall circuit is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$30 \mu ~\mathrm{W}$</tex>, and the average time for each measurement of humidity is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$9.4 \mu ~\mathrm{s}$</tex>.