Power supply

Abstract

The invention relates to a power supply, comprising a transformer, a controller and a frequency control circuit, wherein the controller is connected with the transformer; the frequency control circuit is connected with the controller and comprises a resistor (Rf), a fourth resistor (Rf-4) and a third resistor (Rf-3); the resistor (Rf), the fourth resistor (Rf-4) and the third resistor (Rf-3) are sequentially connected between an adjustment driving frequency pin of the controller and a voltage feedback pin of the controller; and the base electrode of a triode (Q1) is connected with the common terminal of the fourth resistor (Rf-4) and the third resistor (Rf-3), the collector electrode of the triode (Q1) is connected with an RI pin, and the emitting electrode of the triode (Q1) is connected with the common terminal of the resistor (Rf) and the fourth resistor (Rf-4). The resistance of the resistor connected with the related pin of the control is adjusted by the frequency control circuit, thus the performances of a power supply system can be ensured not to be influenced in the range of a rated load, the power system can safely operate under the condition that the output exceeds the rated power without changing the original design of the power supply drastically, and the control is simply and is realized easily.

Description

technical field [0001] The invention relates to the field of power supplies, in particular to a power supply capable of outputting high power in a short time. Background technique [0002] At present, most of the small and medium power power supplies adopt the flyback topology. see figure 1 The power supply includes an input rectifier circuit 11, a transformer 13 and an output rectifier circuit 15 connected in sequence, and also includes a controller 12 connected between the input rectifier circuit 11 and the transformer 13, and a power switch connected with the controller 12 and the transformer 13 14. The input rectification circuit 11 is connected to AC power, and the output rectification circuit 15 is connected to loads. [0003] After the alternating current is rectified by the input rectifier circuit 11, the input transformer 13 is transformed and adjusted, and then rectified by the output rectifier circuit 15 to provide electric energy to the load. The controller 1...

AI Technical Summary

Problems solved by technology

[0006] The maximum output power of the above-mentioned power supply is the rated full-load power with the maximum load. When the power supply is used in printers, scanners and other instruments, it is required that the power supply can output more than twice its rated power for a short time. At this time, the power supply will be damaged by the transformer. 13 saturate and cause the fryer

[0007] In the prior art, firstly, the power supply meets the requirements by reducing the inductance of the transformer 13, but this may cause the machine to explode during normal startup, and also affect the performance of the system under normal load; secondly, through the design Implemented with a power system with a lot of headroom, but the size and cost of that power supply will be much higher

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