High integration and Moore's Law are very effective in reducing the size of the device, but not very good for DC (DC/DC) converters, because power converters often take up 30% to 50% of the system space. So, how can we break through this bottleneck?
Increasing the frequency of work is undoubtedly an obvious solution. Most point-of-load regulators are switching converters with a buck topology. Increasing the switching frequency reduces the inductance and capacitance required to meet the regulator's design specifications. Since inductors and capacitors typically occupy most of the DC/DC converter space, as shown in Figure 1(a), this can be very effective. But in fact it is not that simple. So, why is it?
Figure 1: Size comparison of 12VIN at 10kHz, 10AOUT step-down converter (a) and series capacitor (b) at 2MHz per phase
Blindly increasing the frequency increases power consumption. The switching frequency is proportional to the loss, and each time the power is turned on, energy is generated. Among them, the reduction of conversion efficiency and heat dissipation may be the main problems. Today, most converters are limited in frequency to hundreds of kilohertz. Converters with frequencies above 1 MHz are typically of the typical low voltage (5V and below) and low current (less than 1A) types.
It's time to look for other solutions outside of the buck. Buck converters have been the industry's main choice for decades, but they also have fundamental flaws. Now, we have introduced a new DC/DC converter topology that is optimized for high voltage conversion than point-of-load applications. The series capacitor buck converter achieves an operating frequency of several megahertz without affecting efficiency. As shown in Figure 1(b), the overall solution size has been significantly reduced. The TPS54A20-based series capacitor buck converter has the same input and output conditions as the buck converter in Figure 1(a), which is eight times smaller than the latter. That is 1,270 mm3 vs 157 mm3.
Figure 2: Height comparison of 12 VIN at 10 kHz, 10 AOUT buck converter (a) and series capacitor at 2 MHz per phase (b)
The reduction in the size of the regulator gives us more opportunities. Comparing the height profile shown in Figure 2, we can see that the conventional buck converter has a height of 4.8 mm, but for the back part, this height is much higher than the height limit of many systems. The low profile of the series capacitor buck converter (1.2 mm high) allows you to place the regulator on the back of the board, which frees up valuable top side substrate surfaces. It was not realistic to put the entire 10A converter on its back before, because the passive components were too large, but with the TPS54A20, everything is possible.
SPD Surge Protective Device,Lightning Surge Protector
Surge Protection Device (SPD)
It is a device used to limiting instant surge voltage and discharge surge current, it at least including a non-linear component.
Surge protective Device Model Selection
With the impact of international information flow, the rapid development of microelectronic science and technology, communication, computer and automatic control technology, make the building start to go for high quality, high functional area, formed a new building style-intelligent building. As inside the intelligent building there are lot of information system, <<Building lightning protection design norm>> GB50057-94(2002 vision)(hereafter brief as <<lightning protection norm>>) put forward the relative requirement to install the surge protective device, to ensure the information system safely and stable running.
SPD essentially is a equipotential connection material, its model selection is according to the different lightning protection area, different lightning electromagnetic pulse critical and different equipotential connection position, decide which kind of SPD used in the area, to achieve the equipotential connection with the common earth electrode. Our statement will based on SPD's maximum discharge current Imax, continuous operating voltage Uc, protection voltage Up, alarm mode etc.
As per << Lightning Protection Norm>> item 6.4.4 stipulation "SPD must can withstand the expected lightning current flow and should confirm to the additional two requirements: the maximum clamp voltage during surge across, capable to extinguish the power frequency follow-on current after lightning current across." That is the value of SPD's max. clamp voltage add its induction voltage of two ends should be same with the system's basic insulation level and the equipment allowed max. surge voltage.
SPD for Power Supply System Series Selection Guide
The installation of SPD at each lightning protection zone, according to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category, its insulation withstand impulse voltage level can determine the selection of SPD. According to the standard of low voltage electrical appearance, make classification of electrical equipment in accordance with the over voltage category as signal level, loading level, distribution and control level, power supply level. Its insulation withstand impulse voltage level are:1500V,2500V,4000V,6000V. As per to the protected equipment installation position different and the different lightning current of different lightning protection zone, to determine the installation position of SPD for power supply and the break-over capacity.
The installation distance between each level SPD should not more than 10m, the distance between SPD and protected equipment should as short as possible, not more than 10m. If due to limitation of installation position, can't guarantee the installation distance, then need to install decoupling component between each level SPD, make the after class SPD can be protected by the prior class SPD. In the low voltage power supply system, connecting an inductor can achieve the decoupling purpose.
SPD for power supply system specification selection principle
Max. continuous operating voltage: bigger than protected equipment, the system's max. continuous operating voltage.
TT System: Ucâ‰¥1.55Uo (Uo is low voltage system to null line voltage)
TN System: Ucâ‰¥1.15Uo
IT System: Ucâ‰¥1.15Uo(Uo is low voltage system to line voltage)
Voltage Protection Level: less than the insulation withstand impulse voltage of protected equipment
Rated discharge current: determined as per to the lightning situation of the position installed and lightning protection zone.
Normal Working Conditions
-Altitude not exceed 2000m
-Ambient air temperature:
Normal range: -5ÂºC~+40ÂºC
Extend range: -40ÂºC~+80ÂºC
-Relative Humidity: 30% - 90% under indoor temperature condition
- At the place without obviously shaking and shock vibration
- Non-explosion danger medium, non-corrosion gas and dust ( including conductive dust)
-As per Nominal Discharge Current:
- As per Maximum continuous operating voltage:
- As per to poles
- As per auxiliary functions:
a. With remote signal output ( remote alarm function)
b. Without remote signal output
- The continuous applied voltage on the two terminals of SPD should not more than the maximum continuous operating voltage Uc value;
- The voltage protection level Up of SPD should less than the maximum impulse withstand voltage of the protected equipment;
- As per to the different earthing system and protection mode to select the specification accordingly;
1, built-in over-current overheating, temperature control circuit technology.
2, the module design, easy installation, online replacement.
3, low leakage current, fast response time, low residual voltage.
4, alarm indication device, green (normal) v red (fault).
|Rated Operating Voltage Un (V ~)||220V 380V||220V 380V||220V 380V||220V 380V||220V 380V|
|Maximum Continuous Operating Voltage Uc (V ~) kV||385V 420V||385V 420V||385V 420V||385V 420V||385V 420V|
|Voltage Protection Level Up (V ~) kV||â‰¤1.8â‰¤2.2||â‰¤2.4â‰¤2.5||â‰¤2.5â‰¤3.2||â‰¤3.4â‰¤3.7||â‰¤4.0â‰¤4.5|
|L/N(mmÂ²)The Cross Section Of L/N Line||16,25||16,25||16,25||16,25||25,35|
|PE (mmÂ²)The Cross Section Of PE Line||16,25||25,35||25,35||25,35||35|
|Fuse or Switch (A)||63A||63A||63A,100A||63A,100A||63A,125A|
|The Line Section of Communication and Alarm (mmÂ²)||â‰¥ 1.5|
|Relative humidity 25 ÂºC||â‰¤95%|
|Material of Outer Covering||Fiber Glass Reinforced Plastic|
Surge Protector SPD,Surge Protection Device SPD,SPD
Wenzhou Korlen Electric Appliances Co., Ltd. , https://www.zjmannualmotorstarter.com