Overvoltage protection circuit, and integrated circuit and switch converter adopting same

Abstract

Disclosed is an overvoltage protection circuit. An output voltage analog signal which basically changes along with an output voltage synchronously is obtained, and meanwhile, whether the output voltage analog signal and a feedback voltage represent totally opposite information or not is judged. On the basis, whether overvoltage is caused by the fault of a potential-divider network of an external resistor can be judged accurately, so as to provide effective overvoltage protection. Meanwhile, the invention also discloses an integrated circuit and a switch converter applying the overvoltage protection circuit.

Description

technical field [0001] The invention relates to power electronic technology, in particular to an overvoltage protection circuit, an integrated circuit and a switching converter using the same. Background technique [0002] In the switching converter, in order to prevent the circuit overvoltage from causing damage to the load, it is usually necessary to set up an overvoltage protection circuit to shut down for protection when the output voltage is out of control. Existing overvoltage protection circuits such as figure 1 As shown, the control circuit obtains the output voltage sampling value FB1 through a separate or shared resistor divider network. The comparator CMP compares the output voltage sampling value FB1 with the protection reference voltage Vovref to output the overvoltage signal V1. The overvoltage signal V1 can control the control logic CL integrated in the same integrated circuit IC0 to convert the comparison result into an overvoltage protection signal, and tr...

AI Technical Summary

Problems solved by technology

but, figure 1 The overvoltage protection circuit shown makes it necessary to add a pin for output voltage sampling to the integrated circuit that uses it, which increases the chip area

At the same time, the circuit must rely on the resistor divider network outside the chip

However, external circuits are much more likely to fail than integrated circuits

When the connection in the resistor divider network fails, the overvoltage protection circuit will not work properly

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