Voltage converter and method for providing overvoltage protection therein

Abstract

The invention discloses a voltage converter and a method for providing overvoltage protection therein. The voltage converter comprises an input terminal which is used for receiving input voltages, an output terminal which is used for supplying output voltages to loads, a feedback circuit which is used for providing feedback signals representing the output voltages, a main switching circuit comprises a main switch which is used for adjusting the output voltages, and a protection switch comprises a first end coupled to the input terminal and a second end coupled to the main switching circuit. When the feedback signals are greater than a threshold signal, the protection switch is cut off, so that a voltage converter system is stable and reliable.

Description

technical field [0001] The present invention generally relates to an electronic circuit, and in particular to overvoltage protection in a voltage converter. Background technique [0002] figure 1 A schematic diagram of a DC-DC step-down (Buck) converter 100 is shown. The DC-DC step-down conversion circuit 100 includes an upper transistor M1 and a lower transistor M2. The upper transistor M1 is used as a main switch to adjust the output voltage Vout. The upper transistor M1 is coupled to the input voltage Vin. An output capacitor Cout is coupled between the output terminal and the reference ground GND. Typically, the output capacitor Cout can only withstand a limited voltage level. [0003] In some abnormal situations, the upper transistor M1 is short-circuited, and the output voltage Vout rises rapidly. At this time, the output capacitor Cout will be destroyed, and the load may not work normally or be damaged. [0004] In order to prevent the output voltage from being ...

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Problems solved by technology

[0003] Under some abnormal conditions, the upper tube M1 is short-circuited, and the output voltage Vout rises rapidly. At this time, the output capacitor Cout will be destroyed, and the load may not work normally or be damaged.

[0004] In order to prevent the output voltage from being too high, the traditional overvoltage protection sends the feedback signal FB of the output voltage to the control circuit 11. When the signal FB rises to a reference voltage, the control circuit 11 controls the lower tube M2 to turn on, so that the output voltage Vout drops

However, in some cases, overvoltage occurs on the load, and the control circuit 11 cannot work normally

At this time, M2 may not be turned on, so that the overvoltage protection cannot be performed normally

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