Joint connection state detecting circuit of integrated circuit

The invented detection circuit includes the preset resistance of the power source, the ground resistance, the reference bias voltage circuit, the scan bias voltage circuit and the latch unit. The scan bias voltage circuit with the same structure of the reference bias voltage circuit is connected to the pin to be measured. The operating principle of the invention is described in follows. The structure of the circuit including the preset resistance of the power source, the ground resistance and the reference bias voltage circuit coupled is same with the structure of the bias voltage circuit coupled to the pin to be measured. Further, the output signals drawn off respectively are compared. The compared result is sent to the latch unit in order to determine the connecting state of the pin.