Power supply system and power overvoltage safety protection control method

Abstract

A power supply system and power overvoltage safety protection control method, the power supply system comprises an AC / DC switching power supply, a spare battery and at least one DC / DC transformer, and further comprises an overvoltage detection unit which is used for detecting the output voltage of each DC / DC transformer in real time, comparing the output voltage of the DC / DC transformer with a reference voltage and outputting a fault signal. When detecting a dangerous voltage at a later stage output, the system firstly clamps and absorbs a transient dangerous voltage, uses the overvoltage detection unit to detect an overvoltage fault signal synchronously, cuts off the power supply to each transformer from the AC / DC switching power supply and the spare battery, and directly turns off a control chip after converting the fault signal into a proper voltage, thereby realizing the tertiary protection of the system, avoiding the safety risk possibly resulted from the input and output short circuit of the transformer, and improving the reliability of the system.

Description

technical field [0001] The invention relates to a power supply system, in particular to a power supply system with overvoltage safety protection and a power supply overvoltage safety protection control method in an environment where multiple power supply outputs are required in medical equipment. Background technique [0002] In medical equipment such as monitors, the demand for power supply is more complicated, and the power supply is often required to provide a large number of outputs, and the demand for voltage and current is different, basically covering 12V, 5V, 3.3V, etc. Voltage. The bus-type power supply scheme with backup power supply is more and more used in medical equipment. The multi-channel power output required by medical equipment in this power supply mode is converted from the bus power supply VBUS through a converter. The scheme is: through the AC / DC adapter, the DC voltage is converted from the AC alternating current, and the battery is used as the backup...

AI Technical Summary

Problems solved by technology

[0004] However, it is risky to rely solely on the protection function of the control chip itself for power protection, which brings certain hidden dangers to the safety of the power system.

For example, when the switch tube Q is short-circuited due to unexpected circumstances, the converter cannot be turned off by relying on the driving signal of the switch tube Q. At this time, the overvoltage and overcurrent protection of the control chip itself loses its function, ON / OFF The control terminal also cannot control the shutdown of the STEP-DOWN circuit, and the output voltage Vin of the AC / DC adapter will be directly applied to the load. If the system is powered by a battery, the voltage of the battery will also be directly applied to the load, which poses a great risk to system safety.

And it is possible to burn down all the low-voltage power supply parts of the system. Because the busbar not only has high voltage, but also has large energy, it will cause great safety risks when the subsequent stage is burned, such as damage to some functional circuits, explosion, and fire

In addition, the overvoltage detection pin and the voltage feedback pin of the control chip are often integrated together, and when there is a problem with this pin, such as a short circuit to the ground, the control chip U will mistakenly believe that the output voltage is not enough, and instead continue to increase this pin. output voltage, so that not only is no protection implemented, but a more abnormal overvoltage is output

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