Soft-start protection circuit and circuit protection integrated chip

A circuit protection integrated chip, comprising:

• a integrated circuit of the soft-start protection circuit, wherein the soft-start protection circuit comprises:
• a protection chip, a first switch tube, a second switch tube, a third switch tube, a fourth switch tube, a first capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor, wherein
• the first switch tube has a first end connected to a voltage input end, a second end of the first switch tube is connected to a voltage output end, and a control end of the first switch tube is connected to a first end of the fourth switch tube by the second resistor;
• the first resistor and the first capacitor are connected in parallel between the first end of the first switch tube and the control end of the first switch tube;
• a first end of the second switch tube is connected to the voltage input end, and a second end of the second switch tube is connected to the control end of the first switch tube by the third resistor;
• a first end of the fourth resistor is connected to the voltage input end, and a second end of the fourth resistor is connected to a control end of the second switch tube;
• a first end of the fifth resistor is connected to a first end of the fourth switch tube, and a second end of the fifth resistor is connected to both a first end of the sixth resistor and a control end of the third switch tube;
• both a second end of the sixth resistor and a first end of the third switch tube are grounded;
• a second end of the third switch tube is connected to the control end of the second switch tube by the seventh resistor;
• and
• a second end of the fourth switch tube is grounded, and a control end of the fourth switch tube receives an over-current signal of the protection chip, so as to protect a post-stage circuit of the voltage output end;
• wherein the working process of the soft-start protection circuit comprises:
• when the protection chip detects that the bus current recovers to be normal, the protection chip stops outputting the over-current signal CTL, the fourth switch tube is turned on, the voltage of the second end of the third switch tube changes from high to low, the third switch tube is turned off, the voltage of the gate of the second switch tube is a high level, there is no conduction condition, and the second switch tube is turned off, as the voltages at the two ends of the first capacitor do not change suddenly, and the voltage gradually reduces to a preset voltage value corresponding to the protection chip by discharging the first resistor, and thus a condition for starting the first switch tube is reached, the first switch tube is turned on, and the circuit works normally;
• wherein the working process of the soft-start protection circuit comprises:
• when the protection chip detects that a bus current satisfies a preset condition, an over-current signal CTL is outputted, and the fourth switch tube is turned off, resulting in that the third switch tube is turned on, a gate voltage of the second switch tube is low, a conduction condition is reached, the second switch tube is turned on, the voltages at two ends of the third resistor are both VIN, the voltages at a gate of the first switch tube and a source of the first switch tube do not satisfy the conduction condition, and the first switch tube is turned off, thereby achieving the effect of protecting a post-stage circuit of a voltage output end VOUT.