Temperature observation circuit

Abstract

The invention discloses a monitoring circuit capable of identifying whether the temperature of IC chip is higher than the temperature of safe operating area. The invention can monitor the variation of PN junction voltage, which is conducted by forward bias and flowing through a constant current, with temperature. The temperature monitoring circuit comprises a voltage bleeder circuit, a multi-output current source circuit, a temperature sensing circuit, and a voltage amplification circuit. The whole circuit does not use resistor unit. The gain of the voltage amplification circuit is controlled by forming positive feedback loop in the multiple amplification structures of the voltage amplification circuit, so that the circuit has dynamical characteristic of temperature hysteresis. Meanwhile, the positive feedback introduced into the voltage amplification circuit reduces the gain requirement to the voltage amplification circuit, and steepens the jump of the output signal of the circuit.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a circuit for monitoring the temperature of the semiconductor integrated circuit. Background technique [0002] When the temperature of the integrated circuit is higher than the safe operating temperature, the circuit will not work normally, and even damage the devices in the integrated circuit due to overcurrent, so a temperature monitoring circuit is required to monitor the temperature of the circuit. According to needs, a high temperature threshold temperature T1 can be set, and when the circuit temperature reaches T1, the monitoring circuit will give an indication signal that the temperature is too high. According to the application, the indication signal can be used as a trigger signal of an alarm circuit, or used for frequency reduction of a clock signal, a shutdown control signal of a power device, and the like. [0003] At present, a temperature monitoring circuit kn...

AI Technical Summary

Problems solved by technology

In addition, the resistive element will occupy a large chip area

Therefore, the main disadvantages of the circuit in Fig. 1 are: the resistance element is used, which is incompatible with the digital CMOS semiconductor process, which increases the production cost; the number of devices required is large, and the chip area occupied is large; there is no temperature hysteresis characteristic, that is, the temperature The output of the monitoring circuit, the temperature that indicates that the temperature of the circuit is too high, is the same as the temperature that prompts the output to indicate that the temperature of the circuit returns to the normal range. When the temperature of the circuit rises from a low temperature to the threshold temperature T1, the output of the monitoring circuit is reversed. Afterwards, if the temperature control circuit makes the circuit temperature fall back to T1 instead of falling back to T2, which is smaller than T1, the circuit output signal will reverse again, indicating that the temperature control circuit stops working. After that, the circuit temperature rises quickly again. The output of the monitoring circuit is reversed again, and so repeatedly, causing the temperature control circuit to start frequently, and the integrated circuit itself cannot be fully cooled.

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