Abstract: Adaptively controlling drive strength of multiplexed power from supply power rails in a power multiplexing system to a powered circuit is disclosed. A power multiplexing circuit in the power multiplexing system includes a plurality of supply selection circuits (e.g., head switches) each coupled between a respective supply power rail and an output power rail coupled to the powered circuit. The power multiplexing circuit is configured to activate a selected supply selection circuit to switch coupling of an associated supply power rail to the output power rail to power the powered circuit. In one example, the supply selection circuits each include a plurality of power switch selection circuits coupled to an associated supply power rail. The power switch selection circuits are configured to be activated and deactivated by a control circuit to adjust drive strength of a multiplexed supply power rail based on operational conditions, which can account for performance variations.

Abstract: Power rail control systems that include power multiplexing circuits that include cross-current conduction protection are disclosed. Power multiplexing circuit includes supply selection circuits each coupled between a respective supply power rail and an output power rail coupled to a powered circuit. To maintain power to the powered circuit during switching coupling of the output power rail, but while also avoiding current cross-conduction path between supply power rails, diode drop control circuits are provided in supply selection circuits. In diode drop operation mode, the diode drop control circuit associated with a higher voltage supply power rail is configured to regulate voltage supplied by such supply power rail to the output power rail to power the powered circuit. A current cross-conduction path is not created, because diode drop control circuits associated with lower voltage supply power rails are reverse biased to prevent current from flowing through their associated supply selection circuits.

Abstract: Selective coupling of power rails to memory domain(s) in processor-based system, such as to reduce or avoid the need to provide intentional decoupling capacitance in logic domain(s) is disclosed. To avoid or reduce providing additional intentional decoupling capacitance in logic domain to mitigate voltage droops on logic power rail, power rail selection circuit is provided. The power rail selection circuit is configured to couple memory domain to a logic power rail when the logic power rail can satisfy a minimum operating voltage of memory arrays. The additional intrinsic decoupling capacitance of the memory arrays is coupled to the logic power rail. However, if the operating voltage of the logic power rail is scaled down below the minimum operating voltage of the memory arrays when the logic domain does not need higher operation functionality, the power rail selection circuit is configured to couple the memory domain to separate memory power rail.

Abstract: Automatic voltage switching circuits for providing a higher voltage of multiple supply voltages are disclosed. In one aspect, an automatic voltage switching circuit is configured to generate a compare signal indicating which of a first supply voltage and a second supply voltage is a higher voltage. The automatic voltage switching circuit is further configured to generate first and second select signals based on the compare signal, wherein the first and second select signals are in a voltage domain of the higher voltage. Transistors corresponding to the first and second supply voltages control switching the output voltage to the higher voltage in response to the first and second select signals. Biasing the back-gates of the transistors using the output voltage reduces or avoids forward biasing in the body diodes of the transistors, thus reducing the possibility of the output voltage causing interference on a power supply corresponding to a non-activated transistor.

Abstract: Adaptively controlling drive strength of multiplexed power from supply power rails in a power multiplexing system to a powered circuit is disclosed. A power multiplexing circuit in the power multiplexing system includes a plurality of supply selection circuits (e.g., head switches) each coupled between a respective supply power rail and an output power rail coupled to the powered circuit. The power multiplexing circuit is configured to activate a selected supply selection circuit to switch coupling of an associated supply power rail to the output power rail to power the powered circuit. In one example, the supply selection circuits each include a plurality of power switch selection circuits coupled to an associated supply power rail. The power switch selection circuits are configured to be activated and deactivated by a control circuit to adjust drive strength of a multiplexed supply power rail based on operational conditions, which can account for performance variations.

Abstract: Automatic voltage switching circuits for providing a higher voltage of multiple supply voltages are disclosed. In one aspect, an automatic voltage switching circuit is configured to generate a compare signal indicating which of a first supply voltage and a second supply voltage is a higher voltage. The automatic voltage switching circuit is further configured to generate first and second select signals based on the compare signal, wherein the first and second select signals are in a voltage domain of the higher voltage. Transistors corresponding to the first and second supply voltages control switching the output voltage to the higher voltage in response to the first and second select signals. Biasing the back-gates of the transistors using the output voltage reduces or avoids forward biasing in the body diodes of the transistors, thus reducing the possibility of the output voltage causing interference on a power supply corresponding to a non-activated transistor.

Abstract: Power rail control systems that include power multiplexing circuits that include cross-current conduction protection are disclosed. Power multiplexing circuit includes supply selection circuits each coupled between a respective supply power rail and an output power rail coupled to a powered circuit. To maintain power to the powered circuit during switching coupling of the output power rail, but while also avoiding current cross-conduction path between supply power rails, diode drop control circuits are provided in supply selection circuits. In diode drop operation mode, the diode drop control circuit associated with a higher voltage supply power rail is configured to regulate voltage supplied by such supply power rail to the output power rail to power the powered circuit. A current cross-conduction path is not created, because diode drop control circuits associated with lower voltage supply power rails are reverse biased to prevent current from flowing through their associated supply selection circuits.

Abstract: Selective coupling of power rails to memory domain(s) in processor-based system, such as to reduce or avoid the need to provide intentional decoupling capacitance in logic domain(s) is disclosed. To avoid or reduce providing additional intentional decoupling capacitance in logic domain to mitigate voltage droops on logic power rail, power rail selection circuit is provided. The power rail selection circuit is configured to couple memory domain to a logic power rail when the logic power rail can satisfy a minimum operating voltage of memory arrays. The additional intrinsic decoupling capacitance of the memory arrays is coupled to the logic power rail. However, if the operating voltage of the logic power rail is scaled down below the minimum operating voltage of the memory arrays when the logic domain does not need higher operation functionality, the power rail selection circuit is configured to couple the memory domain to separate memory power rail.