electro-thermal | PartQuest™ Explore

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This design represents a simple automotive (12V) coffee cup warmer, with digital thermostat. It is not meant to be a practical design, but rather to show some of the capabilities of modeling multi-discipline electro-thermal systems in SystemVision Cloud.The design includes a "plant" model with both static and dynamic thermal aspects, including a tungsten heater element, conduction and radiation heat transfer, and heat capacitance. A "graphical" model of the temperature sensor includes math function-blocks to set the bandwidth (LPF), gain (sensitivity), offset bias and output voltage limiting. It also includes an output resistance.The closed loop performance of the system depends on the sensor bandwidth and the sampling rate. Try using 1 Hz instead of 0.1 Hz for the pole frequency "FP" in LPF1, and a 0.2 second period for the sample clock. You'll notice that the faster sensor and sampling greatly improves the temperature regulation.The thermostat includes a simple amplifier and a single-bit voltage-to-digital converter, with a threshold level that specifies the temperature regulation set-point. A digital clock and D flip-flop sample and preserve the desired state of the heater switch during each clock cycle.

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Copy of Analog LED Driver with Thermal Protection using FloTHERM Netlist - on Thu, 10/09/2025 - 17:35

Designer

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This&nbsp;LED spotlight example demonstrates the value of simulating both the electrical and thermal&nbsp;aspects of power dissipating circuits together, simultaneously.In this design, a Vishay NTCLE100&nbsp;Thermistor is used in a detection circuit to monitor&nbsp;the enclosure temperature. It is used for&nbsp;thermal shut-down protection, to keep the enclosure temperature well below the "Tg" (glass transition temperature) of the spotlight's Nylon 6 polymer&nbsp;lens. This is particularly helpful when operating at higher&nbsp;external ambient temperatures.The "Thermals" (thermal dynamics) model was automatically generated from a full 3D-CFD analysis of the spotlight board layout and enclosure, using FloTHERM. The model is in the IEEE Standard VHDL-AMS format, so it can be directly imported into the SystemVision "1D" circuit and system simulation context. The ability to include an accurate model of the thermal environment is key to having&nbsp;"thermally-aware" circuit function design&nbsp;and board layout&nbsp;processes.

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Copy of Analog LED Driver with Thermal Protection using FloTHERM Netlist - on Thu, 10/09/2025 - 15:23

Designer

Description

This&nbsp;LED spotlight example demonstrates the value of simulating both the electrical and thermal&nbsp;aspects of power dissipating circuits together, simultaneously.In this design, a Vishay NTCLE100&nbsp;Thermistor is used in a detection circuit to monitor&nbsp;the enclosure temperature. It is used for&nbsp;thermal shut-down protection, to keep the enclosure temperature well below the "Tg" (glass transition temperature) of the spotlight's Nylon 6 polymer&nbsp;lens. This is particularly helpful when operating at higher&nbsp;external ambient temperatures.The "Thermals" (thermal dynamics) model was automatically generated from a full 3D-CFD analysis of the spotlight board layout and enclosure, using FloTHERM. The model is in the IEEE Standard VHDL-AMS format, so it can be directly imported into the SystemVision "1D" circuit and system simulation context. The ability to include an accurate model of the thermal environment is key to having&nbsp;"thermally-aware" circuit function design&nbsp;and board layout&nbsp;processes.

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Copy of Analog LED Driver with Thermal Protection using FloTHERM Netlist - on Thu, 10/09/2025 - 18:19

Designer

Description

This&nbsp;LED spotlight example demonstrates the value of simulating both the electrical and thermal&nbsp;aspects of power dissipating circuits together, simultaneously.In this design, a Vishay NTCLE100&nbsp;Thermistor is used in a detection circuit to monitor&nbsp;the enclosure temperature. It is used for&nbsp;thermal shut-down protection, to keep the enclosure temperature well below the "Tg" (glass transition temperature) of the spotlight's Nylon 6 polymer&nbsp;lens. This is particularly helpful when operating at higher&nbsp;external ambient temperatures.The "Thermals" (thermal dynamics) model was automatically generated from a full 3D-CFD analysis of the spotlight board layout and enclosure, using FloTHERM. The model is in the IEEE Standard VHDL-AMS format, so it can be directly imported into the SystemVision "1D" circuit and system simulation context. The ability to include an accurate model of the thermal environment is key to having&nbsp;"thermally-aware" circuit function design&nbsp;and board layout&nbsp;processes.

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Copy of Analog LED Driver with Thermal Protection using FloTHERM Netlist - on Thu, 10/09/2025 - 18:01

Designer

Description

This&nbsp;LED spotlight example demonstrates the value of simulating both the electrical and thermal&nbsp;aspects of power dissipating circuits together, simultaneously.In this design, a Vishay NTCLE100&nbsp;Thermistor is used in a detection circuit to monitor&nbsp;the enclosure temperature. It is used for&nbsp;thermal shut-down protection, to keep the enclosure temperature well below the "Tg" (glass transition temperature) of the spotlight's Nylon 6 polymer&nbsp;lens. This is particularly helpful when operating at higher&nbsp;external ambient temperatures.The "Thermals" (thermal dynamics) model was automatically generated from a full 3D-CFD analysis of the spotlight board layout and enclosure, using FloTHERM. The model is in the IEEE Standard VHDL-AMS format, so it can be directly imported into the SystemVision "1D" circuit and system simulation context. The ability to include an accurate model of the thermal environment is key to having&nbsp;"thermally-aware" circuit function design&nbsp;and board layout&nbsp;processes.

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Copy of Modeling Transistor Amplifier Self-Heating - Thermal Network - on Wed, 09/24/2025 - 12:23

Designer

Description

This example shows the importance of modeling thermal interaction effects, or "thermal crosstalk", in power dissipating circuits. The "design" is a simple transistor amplifier, using just an 8 Ohm pull-up resistor and an active pull-down NPN BJT. Both of these models are from our "Thermal and Electro-thermal" Components Library, so they have a thermal port that can connect to an external thermal network. These models output all power dissipated in the device as a thermal heat-flow into that network.

The thermal network includes the heat-sink's heat capacitance (0.1 J/degC) and heat transfer resistance to the ambient (10 degC/Watt). This assumes the resistor and transistor contribute heat to the same heat-sink. The transistor's thermal heat-flow path also includes an 8.8 degC/Watt resistance, to represent the Junction-to-Lead Thermal Resistance as published in the device datasheet (Diodes Inc. FZT869).

From the simulation results it is clear that the heat-sink temperature rises to nearly 120 degC (purple waveform), causing the transistor's junction temperature to approach 150 degC (average, red waveform). This is significantly higher than the value predicted in the companion design example: "Modeling Transistor Amplifier Self-Heating - Hot Part Monitor", which assumed the two devices were thermally isolated.

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Copy of Modeling Transistor Amplifier Self-Heating - Thermal Network - on Wed, 09/17/2025 - 20:36

Designer

Description

This example shows the importance of modeling thermal interaction effects, or "thermal crosstalk", in power dissipating circuits. The "design" is a simple transistor amplifier, using just an 8 Ohm pull-up resistor and an active pull-down NPN BJT. Both of these models are from our "Thermal and Electro-thermal" Components Library, so they have a thermal port that can connect to an external thermal network. These models output all power dissipated in the device as a thermal heat-flow into that network.

The thermal network includes the heat-sink's heat capacitance (0.1 J/degC) and heat transfer resistance to the ambient (10 degC/Watt). This assumes the resistor and transistor contribute heat to the same heat-sink. The transistor's thermal heat-flow path also includes an 8.8 degC/Watt resistance, to represent the Junction-to-Lead Thermal Resistance as published in the device datasheet (Diodes Inc. FZT869).

From the simulation results it is clear that the heat-sink temperature rises to nearly 120 degC (purple waveform), causing the transistor's junction temperature to approach 150 degC (average, red waveform). This is significantly higher than the value predicted in the companion design example: "Modeling Transistor Amplifier Self-Heating - Hot Part Monitor", which assumed the two devices were thermally isolated.

About text formats

Copy of Modeling Transistor Amplifier Self-Heating - Thermal Network - on Wed, 09/17/2025 - 08:04

Designer

Description

This example shows the importance of modeling thermal interaction effects, or "thermal crosstalk", in power dissipating circuits. The "design" is a simple transistor amplifier, using just an 8 Ohm pull-up resistor and an active pull-down NPN BJT. Both of these models are from our "Thermal and Electro-thermal" Components Library, so they have a thermal port that can connect to an external thermal network. These models output all power dissipated in the device as a thermal heat-flow into that network.

The thermal network includes the heat-sink's heat capacitance (0.1 J/degC) and heat transfer resistance to the ambient (10 degC/Watt). This assumes the resistor and transistor contribute heat to the same heat-sink. The transistor's thermal heat-flow path also includes an 8.8 degC/Watt resistance, to represent the Junction-to-Lead Thermal Resistance as published in the device datasheet (Diodes Inc. FZT869).

From the simulation results it is clear that the heat-sink temperature rises to nearly 120 degC (purple waveform), causing the transistor's junction temperature to approach 150 degC (average, red waveform). This is significantly higher than the value predicted in the companion design example: "Modeling Transistor Amplifier Self-Heating - Hot Part Monitor", which assumed the two devices were thermally isolated.

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Test Fuse with Lamp Load JSAE 2025

Designer

Description

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Modeling Transistor Amplifier Self-Heating - Thermal Network JSAE 2025

Designer

Description

This example shows the importance of modeling thermal interaction effects, or "thermal crosstalk", in power dissipating circuits. The "design" is a simple transistor amplifier, using just an 8 Ohm pull-up resistor and an active pull-down NPN BJT. Both of these models are from our "Thermal and Electro-thermal" Components Library, so they have a thermal port that can connect to an external thermal network. These models output all power dissipated in the device as a thermal heat-flow into that network.

The thermal network includes the heat-sink's heat capacitance (0.1 J/degC) and heat transfer resistance to the ambient (10 degC/Watt). This assumes the resistor and transistor contribute heat to the same heat-sink. The transistor's thermal heat-flow path also includes an 8.8 degC/Watt resistance, to represent the Junction-to-Lead Thermal Resistance as published in the device datasheet (Diodes Inc. FZT869).

From the simulation results it is clear that the heat-sink temperature rises to nearly 120 degC (purple waveform), causing the transistor's junction temperature to approach 150 degC (average, red waveform). This is significantly higher than the value predicted in the companion design example: "Modeling Transistor Amplifier Self-Heating - Hot Part Monitor", which assumed the two devices were thermally isolated.

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