Thermal protection of SMPS switch
AssigneeNXP B.V.
InventorHermanus Johannes Effing
Life of this patent
Estimating the term…
Abstract
A circuit for measuring temperature of an external switch is disclosed. The circuit includes a variable resistor, a switch coupled to the variable resistor in series, a fixed value resistor coupled to the variable resistor and a comparator coupled between the variable resistor and the fixed value resistor. The circuit is configured to compare voltage drop between a drain and a source of the external switch when the external switch is in ON state with voltage drop at the variable resistor and output a signal to indicate an overtemperature based on the comparing.
Claims8
A circuit for measuring temperature of an external switch, the circuit comprising:
- a variable resistor;
- a switch coupled to the variable resistor in series;
- a fixed value resistor coupled to the variable resistor;
- and
- a comparator coupled between the variable resistor and the fixed value resistor;
- wherein the circuit is configured to compare voltage drop between a drain and a source of the external switch when the external switch is in ON state with voltage drop at the variable resistor and output a signal to indicate an overtemperature based on the comparing.
An integrated circuit, comprising:
- a port for receiving a drive signal for driving the switch;
- a port for outputting an overtemperature signal;
- a port for receiving an input from a drain of the external switch;
- a port for receiving an input from a source of the external switch
- a circuit for measuring temperature of an external switch, wherein the circuit includes:
- a variable resistor;
- a switch coupled to the variable resistor in series;
- a fixed value resistor coupled to the variable resistor;
- and
- a comparator coupled between the variable resistor and the fixed value resistor;
- wherein the circuit is configured to compare voltage drop between a drain and a source of the external switch when the external switch is in ON state with voltage drop at the variable resistor and output a signal to indicate an overtemperature based on the comparing.
Dependencies are inferred from the claim text.