Thermal Pins in CAB760M12HM3 Module

Harshil

Hi,

I am trying to connect gate driver circuit to CAB760M12HM in LTspice. While i want to see the change in temperature in module and overall efect on the output, I am unable to find the relation between three different thermal terminals i.e. Tc, TjQ1 and TjD1. I want to clearify which terminal is represented by which temperature? Tc is ambient temperature but the other 2 are which temperature terminal please clarify.

Thankyou

Forum_Moderator

Thank you for your post, it has been approved and we will respond as soon as possible.

Bdeboi

Hi Harshil,

Tc1, TjQ1, and TjD1 all relate to each other via a 3rd order Cauer network. Below is an example of what such a network would look like. Tc1 is the temperature of the baseplate, and is usually attached to some sort of coolant. You can imagine that, if Tc1 was left floating (open), then it would mean that there is nothing pulling heat from the baseplate.

TjQ1 is the temperature of the MOSFET at a given switch position. TjD1 is the temperature of an antiparallel diode at a given switch position, if it exists. For modules such as the CAB760M12HM3, there are no schottky diodes, and therefore the TjD1 pins do not do anything.

To summarize with a few thoughts:

1. In the SPICE model download folder, you can read the SPICE model user guide for more info on the thermal ports
2. In the SPICE model download folder, you can open some example circuits to see how the Tj and Tc ports should be configured
3. The TjQ/TjD pins are intended to be measurement pins
4. The Tc pins can be attached to a voltage source and resistor to simulate a coolant and thermal resistance to the baseplate
5. The TjQ/TjD pins can be directly connected to a voltage source to force the junction temperature
6. The initial temperature of the baseplate and junction will be defined by the .TEMP global LTspice temperature
7. Setting 'Thermals=1' in the Spiceline (can be accessed by right-clicking the module symbol) will enable the third-order Cauer electro-thermal model.
8. Setting 'Thermals=0' in the Spiceline will disable the Cauer model, and instead set a static junction temperature throughout the entire sim, defined by .TEMP

Let me know if you have any further questions, and I can provide more details.

Thanks,

Brian

BlakeNelson

Hi Harshil,

I hope that this answered your question.

I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.

Blake