IGBTs –Insulated Gate Bipolar Transistor. IGBTs have always been known for high efficiency and fast switching semiconductor devices which transfers the electrical power to various appliances such as refrigerators, air conditioners etc. The article will throw light on the advantage of next generation IGBT (IGBT4) that is “Saving of Energy” and this is done by the characteristics and operational behavior of these new generation IGBTs.
Nowadays, energy saving is the prime objective of every country. Demand for the energy is increasing and moreover, factors like rising energy costs, lack of availability of fossil fuels and to reduce the emission of CO2 justify the reason fro energy saving.
Energy can be saved by using efficient machines like inverters which further require optimized power semiconductor components and devices and IGBTs have become one of the significant components to achieve the goal. The next generation IGBT is available in three chip versions which are low, medium and high power IGBT modules.
Low version is IGBT4 – T-4 which gives nominal current from 10 to 300 A with fast switching behavior.
Medium version power module is IGBT4 – E-4 having good on-state and switching characteristics and gives current in the range of 150 to 1000 A.
The other one is IGBT4 – P-4 for high power modules with current greater than 900 A having soft switching characteristics.
The new IGBT4 generation is better than previous IGBT3 in terms of electrical performance. The former is a 1200V optimized chip operates at 1500C as compare to the latter one which is a 600V optimized chip operating at 1250C. Among these two IGBTs, the one which is operating at higher temperature leads to high output power.
Switching characteristics in the IGBT behavior is of real concern. The E-versions of the IGBTs are softer as compare to T-versions i.e. they have a soft switching characteristic. This type of characteristics is compared at nominal current as a function of DC link voltage. Another factor which is significant in the success of new generation IGBTs chips is the low static and dynamic losses with higher output. In addition to this, in the insulated gate transistors the induction of stray inductance with respect to the gate resistance with turn-on and off losses has a greater influence on the voltage characteristics.
The above described behavior of IGBTs plays a major role in achieving the optimization potential for all the IGBT modules because as the stray inductance increases it is necessary to reduce the switching speed which is further obtained by increasing the external gate resistance. The increased gate resistance leads to higher turn-on losses. Therefore higher stray inductance reduces the softness of IGBTs & diodes that results into the desired potential or output power. Hence the operational behavior of the new generation IGBTs due to all these characteristic results in the efficient method of saving energy.
For more: NAS Knowledge Base www.foxonline.com www.beganto.com
Advancement in Temperature Sensors
The devices which have dense circuits dissipate lot of power. These devices need Temperature sensor to control battery charging and to prevent damage to microprocessor and other expensive components.
Such devices generally use a Fan to control the temperature. In order to increase the battery life Fan is operated only when it is necessary. Temperature sensors are needed here to know the critical temperatures and control the Fan operation.
Temperature sensors are used in monitoring of Portable equipments temperature, CPU temperature,
Since in most cases the output of temperature sensors are non linear, they are first conditioned and amplified before they are processed.
In past, complex circuits were needed to correct non linearity of temperature sensors. Over this, these circuits needed manual calibrations and precision resistors were required to achieve the desired accuracy. Now days, high resolution ADCs are used to digitize the sensor outputs directly.
There are several types of Temperature sensors available. Resistance Temperature Devices (RTD) is accurate and fairly linear. They have range of -200 Deg C to +850 Deg C. Thermistors have highest sensitivity but are most non linear. They work in the range of 0 to 100 Deg C. Semiconductor temperature sensors are most advanced. They are highly accurate and linear. They work in the range of -55 to 150 Deg C. Internal amplifiers can scale the output to convenient values, such as 10mV/°C.
The bandgap temperature sensors are used as the basis for variety of IC temperature sensors to generate either current or voltage outputs.
In some cases where the temperature sensor output is required to be ratio metric with its supply voltage the Ratio metric voltage output sensors are used.
Digital output temperature sensors are used especially in remote applications. Output of sensor is digitized by a sigma-delta modulator. The output of modulator is encoded in a serial digital output signal with a mark-space ratio format that is decoded by microprocessor into either degrees centigrade or degrees Fahrenheit. As this modulation technique is clock independent, it avoids error sources common to other modulation techniques.
For more: NAS Knowledge Base Torex Knowledge Base Fox TCXOs
Nano technology in electronics.
Category: (Integrating techniques)
Whenever we think about Nano technology the first thing comes into the mind is some thing extremely small. Particles in size range 10-9m are known as nano particles or sub-micron Particles. They are also known as quantum dots due to quantum property possessed by them.
- Displays
- High density data storage
- Non-volatile RAM
- Interconnects
- EMI Shielding
- Small multilayer Capacitors
- Optoelectronics Devices
- Optical Fiber Joining/Coating
Nano electronics promises to enhance the power of computer processors more than with conventional semiconductor fabrication techniques. A number of approaches are currently being researched, including new forms of nano lithography, as well as the use of nano materials such as nano wires or small molecules in place of traditional CMOS components.
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