Techniques for junction temperature determination of power switches
AssigneeAnalog Devices International Unlimited Company
InventorBernhard Strzalkowski
Life of this patent
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Abstract
Techniques for determining a temperature measurement of a junction of a power switch are described. A current can be applied to a control node, e.g., gate terminal, of the power switch, such as a field-effect transistor (FET) or an insulated-gate bipolar transistor (IGBT), while the power switch is in a steady-state region in which a gate-to-source voltage (e.g., FET) or a gate-to-emitter voltage (e.g., IGBT) of the power switch is constant. While in the steady-state region, the temperature measurements can be performed, thereby ensuring accuracy of the measurement.
Claims20
A method of determining a junction temperature measurement of a power switch having a control node and an internal control node resistance, the method comprising:
- controlling an application of first and second currents to the internal control node resistance when the power switch is operating within a steady-state region in which a gate-to-source voltage or a gate-to-emitter voltage of the power switch is constant;
- determining a difference between first and second voltage drops across the internal control node resistance of the power switch caused by the corresponding first and second currents applied;
- and
- outputting a signal representing the measurement of the junction temperature of the power switch based on the determined difference.
A circuit configured to determine a junction temperature measurement of a power switch having a control node and an internal control node resistance, the circuit comprising:
- a current source configured to apply first and second currents to the internal control node resistance when the power switch is operating within a steady-state region in which a gate-to-source voltage or a gate-to-emitter voltage of the power switch is constant;
- and
- a calibration and calculation circuit configured to:
- determine a difference between first and second voltage drops across the internal control node resistance of the power switch caused by the corresponding first and second currents applied;
- and
- output a signal representing the measurement of the junction temperature of the power switch based on the determined difference.
A circuit configured to provide a junction temperature measurement of a power switch having a control node and an internal control node resistance, the circuit comprising:
- means for controlling an application of first and second currents to the internal control node resistance when the power switch is operating within a steady-state region in which a gate-to-source voltage or a gate-to-emitter voltage of the power switch is constant;
- means for determining a difference between first and second voltage drops across the internal control node resistance of the power switch caused by the corresponding first and second currents applied;
- and
- means for outputting a signal representing the measurement of the junction temperature of the power switch based on the determined difference.
Dependencies are inferred from the claim text.