Semiconductor device with wake-up unit
AssigneeFreescale Semiconductor, Inc.
InventorsShubhra Singh, Kumar Abhishek, Mukesh Bansal
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Abstract
A semiconductor device having a low power mode includes a buffer circuit associated with an interface pad, a power management controller (PMC), and a wakeup unit for waking up a part of the device from the low power mode. The buffer circuit is disabled in the low power mode by asserting a power on reset (POR) signal associated with the PMC. A wakeup signal is generated and provided to the wakeup unit from an analog power supply associated with the buffer circuit.
Claims2
A semiconductor device having a plurality of I/O pads, wherein the semiconductor device is operable in a low power mode, the semiconductor device comprising:
- at least one interface pad;
- a buffer circuit connected to the interface pad, wherein the buffer circuit includes,
- an input buffer having an input terminal connected to the interface pad for receiving a signal input to the interface pad,
- an output buffer having an output terminal connected to the interface pad and the input terminal of the input buffer, for transmitting a signal to the interface pad, and
- a resistor having a first terminal connected to the interface pad, the input terminal of the input buffer, and the output terminal of the output buffer, and a second terminal for providing a wake-up signal;
- a power management controller (PMC) coupled to said I/O pads and said interface pad for supplying power thereto, wherein power to said I/O pads and said interface pad is disabled during said low power mode by assertion of a power on reset signal of said PMC;
- a first level shifter, connected to the second terminal of the resistor of the buffer circuit, for receiving the wake-up signal and shifting a voltage level of the wake-up signal from a analog supply high operation voltage level to a core operation voltage level;
- and
- a wake-up unit connected to the first level shifter for receiving the level-shifted wake-up signal, wherein the wake-up unit wakes up at least a part of said semiconductor device from said low power mode.
Dependencies are inferred from the claim text.