Dual rail device with power detector
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsYangsyu Lin, Chiting Cheng
Life of this patent
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Abstract
A dual rail device includes a first power domain circuit coupled to a first power supply through a first header control switch and a second power domain circuit coupled to a second power supply. The first and second power supplies have different steady-state voltage levels. The first power domain circuit is interfaced to the second power domain circuit. The device also includes a power detector circuit for providing a control signal for the first header control switch responsive to a voltage level of the second power supply.
Claims20
A method of operating a dual-rail device having a first power domain circuit operable with a first power supply and a second power domain circuit operable with a second power supply, comprising the steps of:
- disconnecting the first power supply from the first power domain circuit;
- detecting a voltage level of the second power supply during ramp up of the second power supply;
- maintaining the first power supply disconnected from the first power domain circuit during ramp up of the second power supply until the second power supply voltage level reaches a rising trigger point;
- detecting a voltage level of the second power supply during ramp down;
- and
- disconnecting the first power supply from the first power domain circuit when the second power supply falls to a falling trigger point during ramp down of the second power supply.
A method of limiting cross-domain leakage current when turning on and off power supplies in a dual-rail device having a first power domain circuit interfaced to a second power domain circuit, the first power domain circuit operable with a first power supply and the second power domain circuit operable with a second power supply, comprising the steps of:
- turning on the first power supply;
- with the first power supply at a first power supply steady state voltage, turning on the second power supply,
- disconnecting the first power supply from the first power domain circuit;
- detecting a voltage level of the second power supply;
- connecting the first power supply to the first power domain circuit when the second power supply reaches a rising trigger point during ramp up of the second power supply;
- turning off the second power supply;
- and
- disconnecting the first power supply from the first power domain circuit when the second power supply falls to a falling trigger point during ramp down of the second power supply.
A method of operating a static random access memory (SRAM), the SRAM having a periphery logic circuit interfaced to an array of SRAM memory cells, the periphery logic circuit operating in a first power domain from a first power supply, and the array of SRAM memory cells operating in a second power domain from a second power supply, wherein the second power supply has a higher steady state voltage than the first power supply, the method comprising the steps of:
- detecting a voltage level of the second power supply when transitioning between a low state and a steady state voltage level;
- and
- controlling a first header control switch coupled between the first power supply and the periphery logic circuit in response to detection of the voltage level of the second power supply.
Dependencies are inferred from the claim text.