Power conversion device and function triggering circuit and function triggering method thereof

The invention discloses a power conversion device and a function triggering circuit and a function triggering method thereof. The power conversion device comprises a transformer and a control module capable of being coupled to the primary side of the transformer, and the function trigger circuit is coupled between the secondary side of the transformer and the control module and comprises a current detection circuit, a delay circuit and a switching circuit. The current detection circuit senses the secondary side of the transformer to generate a delayed detection signal, the delay circuit enables an initial level to be higher than an internal level before the transformer works in a steady state, and the switching circuit selectively generates a function trigger signal based on the detection signal after the transformer works in the steady state, so that the function trigger signal is triggered by the switching circuit. The function trigger signal is used for enabling the control module to execute an over-curren