Power supply device achieving input-series and output-parallel of switching power supply

Abstract

The invention discloses a power supply device achieving input-series and output-parallel of a switching power supply. The power supply device comprises two DC-DC converters. One of the DC-DC converters is a push-pull type converter which operates in an open-loop mode. The other DC-DC converter is a DC-DC converter which operates in a closed-loop mode, and output voltage of the DC-DC converter is stable. The input ends of the converters are connected in series, and the output ends of the converters are connected in parallel. The highest working voltage of the device with the series connection by the method is improved, the loop response of the power supply is good, cost is low, efficiency is high, and implementation is easy.

Description

technical field [0001] The invention relates to a DC-DC converter circuit, in particular to a power supply device for realizing the input series connection and the output parallel connection of a switch power supply. Background technique [0002] In recent years, switching power supply has been widely used because of its small size, high power density and high efficiency. Both industrial and civil use often need to use switching power supplies in parallel to obtain greater output power. figure 1 shows this application, figure 1 In the circuit, under normal circumstances, the DC-DC converter 1 indicated by the number 1 and the DC-DC converter 2 indicated by the number 2 are converters of the same type, and the input terminals Vin+ and Vin- are respectively connected in parallel, and the output terminals Vout+ and Vout- are also connected in parallel respectively. figure 1 This combined switching power supply has extremely strict requirements on DC-DC converter 1 and DC-DC ...

AI Technical Summary

Problems solved by technology

Since their input ends are connected in series, their input currents must be equal. image 3 The circuit cannot work, and will eventually turn off the output due to one of the converters working under light load, resulting in image 3 This series power supply method restarts repeatedly

In another case, the input voltage of the DC-DC converter 1 is very low, and will become lower and lower until the main power switch tube of the DC-DC converter 1 is in the normally-on state, at this time the voltage of the input voltage Vin is Almost all of them are added to the DC-DC converter 2, only the DC-DC converter 2 works normally, the output power cannot be increased, and the beneficial effect of series connection of the input terminals and parallel connection of the output terminals cannot be realized

[0006] Although it is easy to think image 3 However, it is difficult for DC-DC converter 1 and DC-DC converter 2 to ensure a high degree of consistency and cannot work normally, so this solution has not been made public, so it is a "potential connection method"

[0007] In the prior art, the input terminals of two switching power supplies are connected in series, and the output terminals are connected in parallel. There is still no way to make this series power supply work normally.

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