【 Weak current College 】 switching power supply's classification describes 】

Modern switching power supply has two kinds: one is the DC switching power supplies, AC power supply. Book to introduce only the DC switching power supply, its function is to power quality poor indigenous eco power (coarse), such as AC power supply or battery power, converted to meet the requirements of quality high DC voltage (Varitronix). DC-DC switching power supply's core is a DC/DC converters. Therefore, DC switching power supply's classification is dependent on the classification of DC/DC converters. In other words, DC switching power supply's classification and DC/DC converter of classification is basically the same, DC/DC converter of classification is basically a classification of DC switching power supply.

DC-DC/DC converter according to the distance between the man and the output is electrical isolation can be divided into two categories: one category is quarantined as isolated DC/DC converter; the other is not quarantined as non-isolated DC/DC converters.

Isolated DC/DC converter you can also press a number of source to power devices. Single-tube DC/DC converters have forward-(Forward) and Flyback (Flyback). Double tube DC/DC converter has double transistor Flyback (DoubelTransistorForwardConverter), double-tube Flyback (DoubleTransistrF1ybackConverter), push-pull (Push-Pu11Converter) and half-bridge (Ha1f-BridgeConverter). Four pipe DC/DC converter is a full-bridge DC/DC converters (Fu11-BridgeConverter).
Non-isolated DC/DC converters, according to a source of power devices can be divided into single, double and four-pipe. Single-tube DC/DC converter has a total of six, namely buck (Buck) DC/DC converter, bootstrap (Boost) DC/DC converter, boost buck (BuckBoost) DC/DC converters, DC converters, CukDC/ZetaDC/DC converters and DC converter SEPICDC/. In this six single-tube DC/DC converter, Buck and Boost DC/DC converter-is a basic, Buck-Boost, Cuk, Zeta, SEPIC-DC/DC converter is derived from it. Double tube DC/DC converter has a dual-threaded bootstrap (Buck-Boost) DC/DC converters. Four pipe DC/DC converter is commonly used full-bridge DC/DC converters (Fu11-BridgeConverter).

Isolated DC/DC converters in the realization of the output and input electrical isolation, you normally use the transformer, because the functionality of the transformer with variable pressure, so conducive to expand the range of output converter, easy to implement different voltage multi-channel output, or the same voltage of output.

In the power switching valve voltage and current fixed the same converter output power is usually the number of transistors. So the more the number of transistors, DC/DC converter's output power greater than two four-pipe tube output power is doubled single-tube output power is only four tube 1/4.

Non-isolated converters and a combination of isolated converters, you can get a single converter does not have all the features.

According to the energy transmission, DC/DC converter has a one-way transmission and two-directional transport. Have a two-way transmission function of DC/DC converter, you can either side from the power supply side-load, or you can transfer power from the load side power side transmission power.

DC/DC converter can be divided into self-excited and he controlled. With the converter itself is the feedback signals switch tube self-sustained cyclical switch converter is called self-excited converters, such as Lothar Baier (Royer) converter is a typical push-pull self-excited converter. He controlled DC/DC converter of switch device control signal from an external dedicated control circuit.

In accordance with the conditions of switch switching, DC/DC converter can be divided into a hard switch (HardSwitching) and soft-switch (SoftSwitching). Hard switching DC/DC converter of switch device is subjected to flow through the voltage or current, open or shut off the road, open or shut off the process will produce greater overlap loss, the so-called switching loss (Switchingloss). When the converter for a certain time switching losses are considerable, and switching frequency, the greater the higher switching losses, while at the same time in the switch process also provoke circuit inductance and parasitic capacitance of oscillation, brings additional loss, therefore, hard switching DC/DC converter of the switching frequency can not be too high. Soft-switching DC/DC converter of switching valve, open or shut off, or in addition to its voltage is zero, that is, zero voltage switching (Zero-Voltage-Switching, ZVS), or by switching the current zero, i.e. the zero current switch (Zero-Current · Switching, ZCS). This soft-switching mode can significantly decrease the switching loss, as well as the switching process of oscillation, the switching frequency can substantially improve the miniaturization of the converter and modular. Power field effect transistor (MOSFET) is applied more switch component, it has high switching speed, but also have a large parasitic capacitance. It off, in the role of external voltage, the parasitic capacitance is fully charged, if the opening of the former does not let this part of the charge, it will be consumed on the device itself, this is capacitive opening loss. In order to reduce or eliminate such loss, power MOSFET turn-on voltage should be zero (ZVS). Insulated gate bipolar transistors (Insu1atedGateBipo1artansistor, IGBT) is a composite switch device off current trailing will lead to bigger turn-off loss, if you turn off before the current flowing through it drops to zero, you can significantly reduce the switching loss, IGBT use zero-current (ZCS) off. IGBT in zero voltage conditions xiaguan, also can reduce the switching loss, but MOSFET at zero current conditions when opened, and you cannot decrease the capacitive opening loss. Resonant converters (ResonantConverter, RC), quasi resonant converters (Qunsi-TesonantConverter, QRC), more resonant converters (Mu1ti-ResonantConverter, MRC), zero voltage switching PWM converter (ZVSPWMConverter), zero-current switching PWM converter (ZCSPWMConverter), zero voltage switching (Zero-Vo1tage-Transition, ZVT) PWM converter and zero current conversion (Zero-Vo1tage-Transition, ZVT) PWM converters, etc. are considered soft switch DC converter. Power electronic switching devices and zero switching converter technology, promote the development of high-frequency switching power supply.