A short-circuit protection circuit, switching power supply and protection method thereof

Abstract

The invention discloses a short-circuit protection circuit for protecting a power switch, a switching power supply and a protection method thereof. The first input end of the short-circuit protection circuit is coupled to the first end of the power switch, the second input end of the short-circuit protection circuit is coupled to the second end of the power switch, and the output end of the short-circuit protection circuit provides a short-circuit protection signal, wherein the short-circuit protection circuit includes a transistor, the transistor has a threshold voltage; if and only when the power switch is turned on, the short circuit protection circuit compares the difference voltage between the first terminal and the second terminal of the power switch with the threshold voltage of the transistor; and when the difference When the voltage is greater than the threshold voltage of the transistor, the short circuit protection signal is converted to an active state for turning off the power switch. The segment protection circuit, switching power supply and protection method disclosed by the invention have the advantages of simple circuit, low precision requirement, fast response and high reliability.

Description

technical field [0001] The present invention relates to a circuit, specifically but not limited to a short circuit protection circuit and a protection method for a power switch. Background technique [0002] Switching power supplies are widely used to convert input voltages into output voltages for powering loads due to their many advantages such as high efficiency and high current carrying capacity. The output voltage is often regulated by adjusting the duty cycle of the power switch, where the duty cycle is the ratio of the on-time to the period. Switching power supplies have a variety of topologies, such as boost voltage converters, step-down voltage converters, flyback voltage converters, etc. [0003] figure 1 A conventional boost voltage converter is shown, which converts an input voltage Vin at an input node IN into an output voltage Vout higher than the input voltage Vin and provides it at an output node OUT. The output voltage Vout is obtained through the switchi...

AI Technical Summary

Problems solved by technology

However, in this case, higher accuracy requirements are required for the current comparator

And the current comparator often has a certain hysteresis, so when the detected current signal is greater than the maximum current reference value, the actual current is often much greater than the maximum current reference value, and the power switch may still be damaged in this case

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