Positive temperature coefficient type piezoresistor

Abstract

The invention discloses a positive temperature coefficient type piezoresistor. The piezoresistor material is mainly prepared from the following raw materials in percentage by mole: 96.0-97.0% of ZnO,0.7-0.8% of Bi2O3, 0.5-0.8% of TiO2, 0.7-1.0% of Co2O3, 0.1-0.3% of Ni2O3, 0-0.1% of BaCO3, 0.2-0.3% of MnCO3, 0.2-0.3% of SnO2, 0.045-0.1% of Al(NO3)3.9H2O, 0.25-0.3% of Sb2O3, 0.018-0.02% of SrCO3,and 0-0.1% of H3BO3. The invention also discloses a manufacturing method of the piezoresistor. The manufacturing method comprises the following main steps: preparing the main material, preparing slurry, granulating, and sintering to obtain a finished product. Within a certain temperature range, the voltage-sensitive voltage of the circuit rises along with the rise of the temperature; and when thetemperature exceeds a certain threshold value, the voltage-sensitive voltage is reduced along with the rise of the temperature. According to the invention, the amplification phenomenon of the currentconcentration effect of the traditional negative temperature coefficient type piezoresistor is avoided. The working capability of the piezoresistor in a high-temperature environment is well maintained, the piezoresistor can better protect equipment and circuits, and the reliability of the product is ensured.

Description

technical field [0001] The invention relates to a positive temperature coefficient varistor and a manufacturing method of the varistor, belonging to the technical field of electronic component preparation. Background technique [0002] Varistor is a solid-state voltage-sensitive element with nonlinear volt-ampere characteristics and the function of suppressing transient overvoltage. Since the ZnO varistor developed by Matsushita Electric in Japan was first used in color TV in 1968, it is now used Widely used in power electronic circuits to protect the circuit from possible damage due to instantaneous voltage mutations in the power supply system. From the perspective of the working principle of the varistor, when the high voltage comes, the resistance value of the varistor drops suddenly and the current is shunted to prevent the load circuit from being damaged or disturbed by the excessive instantaneous voltage. However, from a microscopic point of view, due to the influence...

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Problems solved by technology

At the same time, the varistor will also generate heat under the impact of current, and the varistor voltage of the traditional negative temperature coefficient varistor will also decrease when the temperature rises, which leads to a small area of ​​low-voltage sensitive voltage on the ceramic chip. The further reduction of the varistor voltage intensifies the current concentration effect, which further increases the temperature in these areas, forming a vicious circle

eventually lead to the failure of the varistor

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