Temperature detecting apparatus, temperature detecting circuit and power semiconductor module

Abstract

A temperature detecting apparatus includes a temperature detecting circuit configured to output a first pulse signal according to a temperature detected by a temperature sensor, and an insulating transformer configured to transmit the first pulse signal to an integrated circuit which is operated by an operation voltage different from that of the temperature detecting circuit. The insulating transformer is installed between the temperature detecting circuit and the integrated circuit. The temperature detecting circuit and the insulating transformer are mounted on a common substrate.

1 . A temperature detecting apparatus, comprising:
 a temperature detecting circuit configured to output a first pulse signal according to a temperature detected by a temperature sensor; and   an insulating transformer configured to transmit the first pulse signal to an integrated circuit which is operated by an operation voltage different from that of the temperature detecting circuit, the insulating transformer being installed between the temperature detecting circuit and the integrated circuit,   wherein the temperature detecting circuit and the insulating transformer are mounted on a common substrate.   
     
     
         2 . The temperature detecting apparatus of  claim 1 , wherein the insulating transformer comprises a primary coil through which a current flows based on the first pulse signal from the temperature detecting circuit and a secondary coil configured to generate a current to be transmitted to the integrated circuit, the primary coil and the secondary coil being formed at upper and lower portions of the insulating transformer with a dielectric layer interposed therebetween. 
     
     
         3 . The temperature detecting apparatus of  claim 1 , wherein when the temperature detected by the temperature sensor reaches a predetermined limit value, the temperature detecting circuit outputs a second pulse signal and the insulating transformer transmits the second pulse signal from the temperature detecting circuit to the integrated circuit. 
     
     
         4 . The temperature detecting apparatus of  claim 1 , wherein a pulse generator is configured to shape pulse widths of a high level and a low level of the first pulse signal or the second pulse signal, and generate and output a pulse having a width smaller than those of the pulse signals, the pulse generator being installed in the vicinity of the primary coil of the insulating transformer. 
     
     
         5 . The temperature detecting apparatus of  claim 4 , wherein a signal demodulation circuit is configured behind the secondary coil, the signal demodulation circuit configured to demodulate a pulse signal, the pulse width of which is shaped by the pulse generator into a signal having the original pulse width, the secondary coil of the insulating transformer configured to generate a current to be transmitted to the integrated circuit. 
     
     
         6 . A temperature detecting circuit, comprising:
 an AD conversion circuit configured to convert a temperature detection signal from a temperature sensor into a digital temperature detection signal;   a triangular wave generation circuit configured to output a digital signal equivalent to a triangular waveform as a time series; and   a comparator configured to compare the digital temperature detection signal output from the AD conversion circuit and the digital signal output from the triangular wave generation circuit and output a duty signal.   
     
     
         7 . The temperature detecting circuit of  claim 6 , wherein a period for executing the comparison process in the comparator is composed of four cycles, in which one cycle is defined as a section from a maximum value of the triangular waveform to a next maximum value thereof or a section from a minimum value of the triangular wave to a next minimum value thereof. 
     
     
         8 . The temperature detecting circuit of  claim 7 , wherein a duty ratio is determined by the first two cycles during one period for executing the comparison process. 
     
     
         9 . The temperature detecting circuit of  claim 6 , wherein when a temperature detected by the temperature sensor reaches a limit value, a detection signal is output from the comparator. 
     
     
         10 . The temperature detecting circuit of  claim 6 , wherein the temperature sensor comprises an element configured to operate with a constant current, the voltage of the element changing in response to a temperature. 
     
     
         11 . The temperature detecting circuit of  claim 10 , wherein a constant current source is configured to flow a current to the temperature sensor and include a current mirror circuit and change the current flowing to the temperature sensor based on a value of a resistor connected to the current mirror circuit. 
     
     
         12 . A power semiconductor module, comprising:
 a power element circuit configured by a power switching element;   a temperature detecting diode configure to measure a temperature of the power switching element; and   a temperature detecting circuit configured to detect a temperature by a voltage signal from the temperature detecting diode,   wherein the temperature detecting diode and the temperature detecting circuit are formed on a single chip as an SOI structure.   
     
     
         13 . The power semiconductor module of  claim 12 , wherein the chip and the power element circuit are formed on a common frame and installed in a single package.