TECHNICAL FIELD

The present invention relates generally to a device and a method for controlling the temperature of a multi-die power module.

BACKGROUND ART

Due to limitations in semiconductor manufacturing processes, there is a practical limit in the total semiconductor area for a single power die. Hence, a high power module typically contains several dies in parallel to achieve a given current rating.

However, due to non-ideal constraints on geometry and electrical parameter variations, the temperature distribution within the set of parallel dies is typically non-uniform. As a consequence, the hottest die limits the total amount of power the module can dissipate and the non-uniform temperature distribution causes unequal aging of each die, limiting the effectiveness of using parallel devices.

The present invention aims to allow a temperature control of a multi-die power module that is reliable using a closed-loop temperature control in order to increase the lifespan of the multi-die power module by reducing local hot spot temperatures.

SUMMARY OF INVENTION

To that end, the present invention concerns a method for controlling the temperature of a multi-die power module comprising plural dies, a multi-die temperature control device receiving an input signal and driving independently the dies of the multi-die power module, characterized in that the method is executed by the multi-die temperature control device and comprises the steps of:obtaining a signal that is representative of the temperature of one die among the dies of the multi-die power module when the die is not conducting,obtaining signals that are representative of a reference temperature that is dependent of the temperature of all the dies of the multi-die power module when the dies are not conducting,comparing the signal that is representative of the temperature of one die to the signal that is representative of the reference temperature,reducing the duration of the conducting time of the die or reducing the duration of the conducting time of the other dies of the multi-die power module according to the comparison result.

The present invention concerns also a multi-die temperature control device that controls the temperature of a multi-die power module comprising plural dies, the multi-die temperature control device receiving an input signal and driving independently the dies of the multi-die power module, characterized in that the multi-die temperature control device comprises:means for obtaining a signal that is representative of the temperature of one die among the dies of the multi-die power module when the die is not conducting,means for obtaining signals that are representative of a reference temperature that is dependent of the temperature of all the dies of the multi-die power module when the dies are not conducting,means for comparing the signal that is representative of the temperature of one die to the signal that is representative of the reference temperature,means for reducing the duration of the conducting time of the die or reducing the duration of the conducting time of the other dies of the multi-die power module according to the comparison result.

Thus, the multi-die temperature control device is able to balance the temperatures across the set of parallel dies independently of the loading condition and without any additional sensors.

According to a particular feature, the input signal is a pulse width modulated signal composed of consecutive periodic cycles of time and the signal that is representative of the temperature of one die among the dies of the multi-die power module and the signal that is representative of the reference temperature are obtained within the same cycle of time.

Thus, the multi-die temperature control device is able to compare the temperature of one die to the most recent reference temperature. The multi-die temperature control device operation can be updated independently of the number of dies in the system and load condition.

According to a particular feature, the signal that is representative of the temperature of one die and the signal that is representative of the reference temperature are obtained by providing a current to the gate of the die and to the gates of the dies.

Thus, only one circuit is necessary to acquire the temperature of one die and the reference temperature. A low cost and simple method for sensing the temperature can be easily integrated into gate drivers for power devices.

According to a particular feature, the signal that is representative of the reference temperature is representative of an equivalent resistor value of the internal gate resistor values of the dies put in parallel.

Thus, the reference temperature is a value close to the mean temperature of the power devices put in parallel. The reference temperature can be deduced without any further complex calculations.

The characteristics of the invention will emerge more clearly from a reading of the following description of example embodiments, the said description being produced with reference to the accompanying drawings.

