The gold electrode NTC thermistor chip produced by EXSENSE Electronic Technology Co., Ltd. is sensitive to temperature changes, which makes it play the role of temperature monitoring and temperature protection in the thermo electric cooler (TEC) in optical communication module.
TEC and its control chip are widely used in the optical communication module industry due to their performance of good temperature control. TEC is made from the Peltier Effect of semiconductor materials. Peltier Effect means that when an electric current passes through a circuit composed of different conductors, in addition to produce the irreversible joule heat, there will be endothermic and exothermic phenomena at the junctions of different conductors with different current directions. As shown in the figure below, TEC includes p-type and N-type pairs (groups), which are connected by electrodes and sandwiched between two ceramic electrodes; When an electric current flows through the TEC, the heat generated by the current will pass from one side to the other side, creating a "hot" side and a "cold" side on the TEC. This is how the TEC heating and cooling.
In the working process of TEC, whether it’s the cooling or heating states, as well as the cooling and heating rates, which are determined by the direction and magnitude of the current passing through it. In order to achieve good temperature control accuracy and stability, a high-performance control chip is needed. This chip can not only provide a reliable and controllable high efficiency power supply for TEC, but also protect TEC materials well.
TEC has the advantages of no noise, no vibration, no refrigerant, small size, light weight and reliable operation, etc., so it is widely used in communication, medical treatment and other special industries, etc., among which the most typical one is the temperature control of laser. The wavelength of the laser is directly proportional to the temperature, and the change of environmental temperature will affect the wavelength. Therefore, the control of the wavelength can be achieved through temperature control. The control of the temperature of the laser tube core is the most effective and basic method to stabilize the laser emission wavelength. Due to the laser wavelength emitted by the laser is very sensitive to temperature, the requirements for temperature accuracy and stability are very high. In normal conditions, TEC and the laser adopt TO encapsulation simultaneously. Thermistor chip has the advantages of high accuracy (can up to ±0.5%, ±1%, ±2%, ±3%), high sensitivity, small size, low cost and so on, which can provide a reliable temperature control environment for TEC.