Switching power supply isolation circuit

Abstract

The invention discloses a switching power supply isolation circuit, which comprises a switching device, a one-way signal transmission device, a one-way conducting device, an inductor and a control module, wherein the switching device and the inductor are sequentially connected with a voltage source in series to form a power supply loop; the one-way conducting device, the inductor and the one-way signal transmission device are sequentially connected with a load in series to form a load loop; the switching device and the one-way signal transmission device are connected with the control module to be controlled by the control module; under the control of the control module, when the switching device is conducted, the one-way signal transmission device is cut off, the power supply loop works and the inductor stores energy; and when the switching device is cut off, the one-way signal transmission device is conducted, the load loop works and the inductor releases energy to supply electricity to the load. The switching power supply isolation circuit disclosed by the invention supplies electricity to the load by the inductor; and electric isolation is achieved by the one-way signal transmission device and the one-way conducting device, so that the switching power supply isolation circuit has the advantages of small size, high efficiency, low cost and the like.

Description

technical field [0001] The present invention relates to the field of power supply technology, and more particularly relates to a switching power supply isolation circuit. Background technique [0002] The topological architectures of existing switching power supplies are divided into three categories: 1. buck architecture; 2. boost architecture; and 3. buck-boost architecture. They correspond to Figure 1a , Figure 1b and Figure 1c Three circuit forms are shown. in, Figure 1a Shown is a step-down circuit, in which Vo=Vin×D, Vo<Vin; Figure 1b Shown is a boost circuit, in this circuit, Vo=Vin / (1-D), Vo>Vin; Figure 1c The buck-boost circuit is shown. In this circuit, Vo=Vin×D / (1-D), when D<0.5, Vo<Vin, when D>0.5, Vo>Vin, among the above three circuits, Vin is the input voltage, Vo is the output voltage, and D is the duty cycle. In terms of circuit form, the above three circuits have one thing in common, that is, the load is always electrically connect...

AI Technical Summary

Problems solved by technology

It can be seen that the power supply circuit using a transformer can achieve the purpose of isolation, but it has the following defects: the production of the transformer requires two or more inductors to be wound on the magnetic core, which brings the disadvantage of high cost; The energy association of inductance (primary inductance and secondary inductance) occurs through a magnetic field, then, according to the principle of electromagnetic induction, there is energy loss when energy is associated between the inductance on both sides (primary inductance and secondary inductance), which brings The problem is low efficiency

[0004] Therefore, although the power supply circuit using a transformer can achieve the isolation effect, the large volume and high cost of the transformer are scruples for the lighting industry, and the efficiency of the isolation circuit has become a technical node that must be broken through to save energy.

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