Abstract: A processor system may include multiple circuits that are each powered by their own power rails. Incomplete cycling of system power may fail to discharge memory circuits, leaving that data vulnerable to unauthorized access upon reboot. A processor system includes a boot detection circuit that, upon detecting a threshold voltage on a first power rail in the bootup sequence, captures voltage measurements on each of the remaining power rails in multiple time periods, wherein the captured voltage measurements may be analyzed to determine whether the voltages on the power rails fully cycled to a sufficiently low voltage and remained there for a sufficient time to ensure that memory circuits adequately discharged. The power system may proceed to generate an indication of complete reset or incomplete reset depending on the voltage measurements stored in the memory. In this way, the confidentiality of data previously stored in the memory circuits is protected.

Abstract: A converter control circuit includes a terminal to be coupled to a switch node. The control circuit includes a valley sensing circuit coupled to the terminal and detects valleys in an oscillating voltage on the switch node. The valley sensing circuit has a first output and asserts a first control signal on the first output indicative of occurrence of a valley. A logic gate has a second output and asserts a second control signal on the second output to turn on a switching transistor. A switch-on control circuit has a first input and a second input. The first input couples to the first output. The second input couples to the second output. The switch-on control circuit asserts a third control signal to turn on the switching transistor responsive to the second control signal indicating that the switching transistor is to be on while the first control indicates a valley.

Abstract: A converter control circuit includes a terminal to be coupled to a switch node. The control circuit includes a valley sensing circuit coupled to the terminal and detects valleys in an oscillating voltage on the switch node. The valley sensing circuit has a first output and asserts a first control signal on the first output indicative of occurrence of a valley. A logic gate has a second output and asserts a second control signal on the second output to turn on a switching transistor. A switch-on control circuit has a first input and a second input. The first input couples to the first output. The second input couples to the second output. The switch-on control circuit asserts a third control signal to turn on the switching transistor responsive to the second control signal indicating that the switching transistor is to be on while the first control indicates a valley.