Apple patents circuit fix to stop power-up glitches
Apple has patented a design for a level shifting circuit that prevents unwanted signal spikes when a device turns on. The invention uses a control signal to hold the output steady until the power supply reaches a stable voltage.
In the filing’s own words
Glitch suppression in a level shifting circuit during power up is disclosed. A level shifting circuit is configured to receive an input signal based on a first voltage domain and generate an output signal based on a second voltage domain. The level shifting circuit is also configured to receive a control signal that is operable to suppress the output signal. A control circuit is configured to provide the control signal to the level shifting circuit such that the output signal fluctuations of the level shifting circuit is suppressed during a power up to a power supply voltage.
What exactly they claim (claim 1)
1. A level shifting circuit comprising: a set of first voltage domain transistors that utilize a first supply voltage, the set of first voltage domain transistors including: a NAND gate configured to receive an input signal and a control signal and generate a first voltage domain signal based on the input signal and the control signal; a first inverter configured to generate a complement of the first voltage domain signal; and a second inverter configured to generate a complement of the control signal; and a set of second voltage domain transistors that utilize a second supply voltage, the set of second voltage domain transistors including: a network of transistors configured to generate, at an output node, a second voltage domain signal based on the first voltage domain signal and a complement of the first voltage domain signal; and an output suppressing transistor configured to couple the output node to ground based on the complement of the control signal.
Facts
- Company
- Apple (APPLE INC.)
- Official title
- Glitch suppression in a level shifting circuit during power up
- Patent number
- US12771349B2
- Application number
- 18988862
- Filed
- Dec 19, 2024
- Granted
- Oct 20, 2026
- Inventors
- 3
- Claims
- 19
Classified under
H03K 19/018521 Electricity & electronicsMore from Apple in Chips & hardware
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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.