Power supply with wide output voltage range

Abstract

The invention discloses a power supply with wide output voltage range, which comprises more than one group of branch circuits, wherein the more than one group of branch circuits comprise a first branch circuit and a second branch circuit, the first branch circuit and the second branch circuit are the same in structure, a first change-over switch is arranged on the first branch circuit, a second change-over switch is arranged on the second branch circuit. When high voltage needs to be output, the output change-over switch is controlled, the second pin and the third pin of the first change-overswitch and the second pin of the second change-over switch are connected, and the output sides of the first branch circuit and the second branch circuit work in a series connection mode. When low voltage needs to be output, the first pin and the third pin of the first change-over switch and the second change-over switch are controlled to be connected, and the positive electrode end and the negative electrode end of the first branch circuit and the second branch circuit are connected with a capacitor C. The invention has the advantages that: the current of each branch of the circuit is simple to sample, isolation is not needed, the cost is low, and the precision is high; the change-over switch has no large peak current and cannot be damaged by large current; through staggered driving, the ripple current of the inductor and the capacitor can be reduced when the inductor and the capacitor are connected in series and in parallel.

Description

technical field [0001] The invention relates to the field of power supplies, in particular to a power supply with a wide output voltage range. Background technique [0002] The maximum output voltage of the power supply module is below 800V, and the power will be limited when the low voltage is below 600V. To increase the output voltage, it is necessary to replace a rectifier diode with a higher withstand voltage, which greatly increases the cost of the device; to increase the output power under low voltage, it is necessary to replace a diode with a larger current capacity, a primary switch tube, and a larger transformer. , the cost and volume are significantly increased, and the conversion efficiency is low at low pressure. [0003] Such as figure 1 As shown, the prior art adopts two-branch outputs, and realizes a wide voltage output range by controlling the two-branch output terminals to work in series and parallel modes. As shown in the figure below, when it is necessa...

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Problems solved by technology

[0005] 1. When GND is selected as the control ground, the current sampling Is1 of the first branch does not need to be isolated, but the current sampling of the second branch needs to be isolated, which increases the cost and complexity of the sampling circuit, and the sampling accuracy will also be affected

[0006] 2. When the output is short-circuited, there is a large rush-out current on the output capacitor. When the output voltage is above 600V, this current may reach above 2kA

However, when working in series mode, the ripple current on the capacitor cannot be reduced by interleaving, which affects the life of the capacitor

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