Protective circuit, operating method for a protective circuit and computer system
View Patent ↗A protective circuit includes an input that provides a first supply voltage, a voltage regulator that provides a second supply voltage based on the first supply voltage, a measuring device that identifies an impedance of the voltage regulator, and a self-locking switching element configured to connect the first supply voltage with the voltage regulator if an impedance of the voltage regulator exceeds a predefined impedance value.
1. A protective circuit comprises:
an input that provides a first supply voltage,
a voltage regulator that provides a second supply voltage based on the first supply voltage,
a measuring device that identifies an impedance of the voltage regulator, and
a self-locking switching element configured to connect the first supply voltage with the voltage regulator if an impedance of the voltage regulator exceeds a predefined impedance value,
wherein the measuring device includes a test resistor that bridges the switching element so that the test resistor and the voltage regulator form a voltage divider.
2. The protective circuit according to claim 1 , wherein the switching element includes an electrical semiconductor switching element or a metal oxide semiconductor field-effect transistor, MOSFET.
3. The protective circuit according to claim 1 , wherein the measuring device further includes a comparator configured to compare a test voltage at a node between the test resistor and the voltage regulator to a reference voltage, and provide a control signal for the switching element at an output of the comparator if the test voltage exceeds the reference voltage.
4. The protective circuit according to claim 1 , wherein the input that provides the first supply voltage is configured to be connected to a voltage rail of a computer power supply unit.
5. A computer system including a computer power supply unit and a system board with the protective circuit according to claim 1 , wherein the computer power supply unit provides the first supply voltage at the input of the protective circuit.
6. A method of operating a protective circuit including an input that provides a first supply voltage, a voltage regulator that provides a second supply voltage based on the first supply voltage, a measuring device that identifies an impedance of the voltage regulator, and a self-locking switching element, wherein the measuring device includes a test resistor that bridges the switching element so that the test resistor and the voltage regulator form a voltage divider, the method comprising:
measuring an impedance of the voltage regulator, wherein measuring the impedance of the voltage regulator comprises supplying a test current at the input of the protective circuit via the test resistor that bridges the switching element, and
closing the switching element if the measured impedance exceeds a predefined impedance value so that the voltage regulator is connected to the first supply voltage.
7. The method according to claim 6 , wherein measuring the impedance of the voltage regulator occurs directly after providing the first supply voltage at the input of the protective circuit.
8. The method according to claim 6 , wherein measuring the impedance of the voltage regulator further comprises:
comparing a test voltage present at a node between the test resistor and the voltage regulator, with a reference voltage.
9. The method according to claim 8 , wherein closing the switching element further comprises:
providing a switching signal to close the switching element to the switching element if the test voltage exceeds the reference voltage.