Switching mode power supply device with detection of malfunctioning

A device comprising:

• a power control switch that operates at a variable duty cycle, having a control terminal and configured to provide power to a load;
• a regulator circuit, configured to monitor a current drawn by the load and provide a compensation voltage level at a compensation node, proportionate to the current draw;
• a driver circuit having an input connected to the compensation node and an output connected to the control terminal of the power switch, configured to monitor the compensation voltage at the compensation node and adjust the duty cycle of the power switch to compensate for the current draw;
• and
• an overload detection circuit coupled to the control terminal of the power switch and configured to temporarily hold the power control switch open in the event that the compensation voltage exceeds a first threshold voltage, and to latch the power control switch open in the event that the compensation a second threshold voltage.

A method comprising:

• comparing a voltage level at an output terminal of a power supply device with a first reference voltage;
• providing a compensation voltage at a compensation node, proportionate to the result of the comparing step;
• varying a duty cycle of a power control switch with reference to the compensation voltage of the providing step, wherein the power control switch provides current to the output terminal of the power supply device;
• comparing the compensation voltage to a second reference voltage;
• opening the power control switch if the compensation voltage exceeds the second reference voltage, wherein the opening results in temporarily turning off the power supply device;
• comparing a biasing current at the compensation node with a current reference;
• and
• latching the power control switch open if the biasing current at the compensation node drops below the current reference, wherein the latching results in permanently turning off the power supply device.