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What is the role of hot plug controller in DC boost circuit

  Hot plug controllers are usually used in high availability systems such as servers, network switches, and other forms of communication infrastructure. This kind of system usually needs to replace the faulty circuit board or module in the charged state, and the system still operates normally. This process is called hot plug.   One use of the hot plug controller is to solve the output end protection problem of the switching DC boost circuit by using the overcurrent and short-circuit protection functions of the hot plug protection circuit.   The DC boost circuit is a switching DC boost circuit. The output voltage is higher than the input voltage, and the polarity of the output voltage is unchanged. It is to raise the low DC voltage provided by the battery to the required voltage value. Its basic working process is: high-frequency oscillation generates low-voltage pulses - pulse transformer boosts to a predetermined voltage value - pulse rectification to obtain high-voltage DC power. Therefore, the DC boost circuit belongs to a type of DC / DC circuit.   When the switch is on, the power supply forms a loop through the inductor switch, and the current is converted into magnetic energy storage in the inductor; When the switch is turned off, the magnetic energy in the inductor is converted into electrical energy at the inductor end, which is negative on the left and positive on the right. This voltage is superimposed on the positive end of the power supply and forms a loop through the diode load to complete the boosting function. When the output overcurrent is over-current, the circuit will sample the peak current of the switch, reduce the duty ratio and cause the output voltage to drop. When the output voltage drops to the input voltage, the overcurrent protection is no longer controlled and the protection fails.   In addition, the output overcurrent point will increase with the increase of the input voltage. When the output is short circuited, the input power supply will form a short circuit loop through the inductor and the booster diode, resulting in power failure. Another disadvantage of boost circuit is that it is not convenient to control off the output. When the control chip is turned off and the switch tube is turned off, the output still has voltage. Unlike buck circuit, it is very convenient to reduce the output voltage to 0 V   Hot plug refers to hot plug. Hot plug function allows users to take out and replace damaged power supply or cards and other components without shutting down the system and cutting off the power supply, thus improving the system's ability of timely recovery, expansibility and flexibility to disasters. If there is no hot plug controller, the module at the load side will have a surge current impact on the power supply when it is plugged in and out, affecting the stability of voltage and the reliability of power supply.   This problem can be solved by the hot plug controller, which can reasonably control the surge current and ensure the safe power on interval. After power on, the hot plug controller can continuously monitor the power supply current to avoid short circuit and overcurrent during normal operation.

What is the role of plug-in power inductors in smart home scenarios?

  In recent years, smart home, also known as smart house, has appeared in people's vision. Generally speaking, it is a networked and intelligent home control system integrating automatic control system, computer network system and network communication technology. Smart home system is based on the residential platform and controls all appliances connected to the home network through mobile app.   Smart home includes eight subsystems; The purpose of these systems is to bring people a safe, convenient, comfortable, artistic, environment-friendly and energy-saving living environment. Smart home not only needs convenient and intelligent control program in software, but also needs to ensure the normal operation of smart home system in hardware.   In this case, various inductors must be used in the circuit to collect data. In addition, there are protection circuit, oscillation circuit, power supply circuit, power amplification circuit and filter circuit; These circuits are without exception, and inductors are one of the indispensable electronic components.   So, what is the role of plug-in power inductors in smart home scenarios?   Current blocking effect: the self induced electromotive force in the coil always opposes the current change in the coil. It can be mainly divided into high-frequency choke coil and low-frequency choke coil.   Tuning and frequency selection: LC tuning circuit can be formed by connecting inductance coil and capacitor in parallel. That is, if the natural oscillation frequency f0 of the circuit is equal to the frequency f of the non AC signal, the inductive reactance and capacitive reactance of the circuit are also equal, so the electromagnetic energy oscillates back and forth between the inductance and capacitance, which is the resonance phenomenon of the LC circuit. During resonance, because the inductive reactance and capacitive reactance of the circuit are equivalent and reverse, the inductive reactance of the total circuit current is the smallest and the current is the largest (referring to the AC signal of f=f0), so the LC resonant circuit has the function of selecting the frequency and can select the AC signal of a certain frequency f.

What is the application scenario of FPGA field programmable gate array

  Field programmable gate array (FPGA) is the product of further development on the basis of programmable devices such as pal (programmable array logic) and gal (general array logic). As a semi custom circuit in the field of application specific integrated circuits (ASIC), it not only solves the shortcomings of custom circuits, but also overcomes the shortcomings of the limited number of programmable devices.   The mainstream manufacturers of field programmable gate array FPGA chips include Xilinx, Altera, lattice and MICROSEMI, of which the first two have a total market share of 88%.   FPGA has a very mature and wide range of applications in the fields of aerospace, military industry and telecommunications. Taking the telecommunication field as an example, in the stage of all-in-one telecommunication equipment, FPGA is applied to network protocol parsing and interface conversion because of its programming flexibility and high performance.   In the nfv scenario, FPGA based on the general server and hypervisor can achieve a 5-fold performance improvement of the network element data plane, and can be managed and arranged by the openstack cyborg hardware acceleration framework.   In the cloud era, FPGA has been used as a basic IAAs resource to provide development services and acceleration services in the public cloud. AWS, Huawei and bat all provide similar general services. Up to now, Intel's Stratix 10 devices have been successfully applied to Microsoft's real-time artificial intelligence cloud platform brainwave project.   FPGA is also widely used in security, industry and other fields. For example, protocols such as video coding and decoding in security field can be processed by FPGA in the process of front-end data acquisition and logic control.   In the industrial field, small-scale FPGA is mainly used to meet the needs of flexibility. In addition, due to its high reliability, FPGA is also widely used in military and aerospace fields. With the construction of 5g network, FPGA will be widely used in the initial stage, and more FPGA will be used in new fields such as artificial intelligence.

What is the difference between electrolytic capacitor and thin film capacitor

  There are electrolyte materials for storing charge inside the electrolytic capacitor, which are divided into positive and negative polarity, similar to batteries, and cannot be reversed. The positive electrode is a metal substrate with an oxide film, and the negative electrode is connected to the electrolyte (solid and non-solid) through a metal plate.   Polar electrolytic capacitors are usually used for power filtering and decoupling in power supply circuits or intermediate and low frequency circuits（ ǒ u) Signal coupling, time constant setting, DC isolation, etc. The non-polar electrolytic capacitor is usually used in the audio frequency divider circuit, the television s correction circuit and the starting circuit of the single-phase motor.   The working voltage of electrolytic capacitor is 4V, 6.3V, 10V, 16V, 25V, 35V, 50V, 63v, 80V, 100V, 160V, 200V, 300V, 400V, 450V and 500V, and the working temperature is - 55 ° ~ + 155 ℃ (4 ~ 500V). It is characterized by large capacity, large volume and polarity. It is generally used for filtering and rectification in DC circuits. At present, the most commonly used electrolytic capacitors are aluminum electrolytic capacitors and tantalum electrolytic capacitors.   A thin film capacitor is a capacitor with a metal foil as an electrode, which is overlapped with a plastic film such as polyethylene, polypropylene, polystyrene or polycarbonate from both ends and wound into a cylindrical structure. According to the type of plastic film, it is also called polyethylene capacitor (also known as mylar capacitor), polypropylene capacitor (also known as PP capacitor), polystyrene capacitor (also known as PS capacitor) and polycarbonate capacitor.   Thin film capacitor is an excellent capacitor because of its many excellent characteristics. Its main characteristics are as follows: non polarity, high insulation impedance, excellent frequency characteristics (wide frequency response), and small dielectric loss.   Therefore, the difference between electrolytic capacitor and thin film capacitor is obvious. The main points are as follows:   Life: electrolytic capacitors generally have life parameters, while thin film capacitors have no life, which can last for decades.   Capacitance value: the capacitance value of electrolytic capacitor can be very large, and high voltage and high capacitance value. The capacitance value of the film capacitor is relatively small. If you need a larger capacitance value, the film capacitor is uncertain.   Size: as for the specifications, the size of the thin film capacitor is larger than that of the electrolytic capacitor.   Polarity: electrolytic capacitors are divided into positive and negative electrodes, while thin film capacitors are not divided into non-polar capacitors. Therefore, it can be separated on the lead. The lead of electrolytic capacitor is one high and one low, and the lead of thin film capacitor is the same length.   Accuracy: the electrolytic capacitance is generally 20%, and the film capacitance is generally 10% and 5%.