Current-limiting circuit of flyback converter and flyback converter

A current-limiting circuit of a flyback converter, wherein the converter comprises a power input end, a power output end, a transformer, a rectifier circuit and a switch unit, a first end of a primary input of the transformer is connected to the power input end, and a second end of the primary input of the transformer is connected to a first end of the switch unit;

• a first end of a secondary output of the transformer is connected to an input end of the rectifier circuit, an output end of the rectifier circuit is connected to the power output end, and a second end of the secondary output of the transformer is grounded;
• the current-limiting circuit comprises a first current measurement unit used for acquiring primary input current of the transformer, a second current measurement unit used for acquiring secondary output current of the transformer, and a first divider, a second divider, a delay unit, a comparison unit and a drive unit;
• a first input end of the first divider is connected to the second current measurement unit, a second input end of the first divider is used for inputting a target current value of the converter, an output end of the first divider is connected to a first input end of the second divider, and a second input end of the second divider is connected to an output end of the delay unit;
• an output end of the second divider is connected to an input end of the delay unit;
• a first input end of the comparison unit is connected to the output end of the delay unit, a second input end of the comparison unit is connected to the first current measurement unit, an output end of the comparison unit is connected to an input end of the drive unit, and an output end of the drive unit is used for being connected to a control end of the switch unit.