Apple patents power supply design that manages startup current spikes
This patent describes a power supply circuit that uses a resistor to limit the surge of electricity when a device first turns on. Once the internal battery-like component is charged, the system automatically switches to a relay or electronic switch to bypass the resistor, depending on how much power the device is using.
In the filing’s own words
A power supply can include a bulk capacitor that receives a DC bus voltage; one or more DC-DC converters that convert the DC bus voltage to a DC output voltage; an inrush current limiting circuit that includes a resistor coupled in series with the bulk capacitor so as to limit an inrush current to the bulk capacitor; and a solid-state switching device that selectively bypasses the resistor once the bulk capacitor is charged; and control circuitry that operates the solid-state switching device to selectively bypass the resistor once the bulk capacitor is charged. The inrush current limiting circuit can further include a relay responsive to the control circuitry that selectively bypasses the resistor under high load conditions once the bulk capacitor is charged; and the control circuitry can further operate the solid-state switching device to selectively bypass the resistor once the bulk capacitor is charged under low load conditions.
What exactly they claim (claim 1)
1. A power supply comprising: one or more input stages that receive an AC input voltage and produce a DC bus voltage; a bulk capacitor that receives the DC bus voltage; a low power DC-DC converter that converts the DC bus voltage to a first DC output voltage; a high power DC-DC converter that converts the DC bus voltage to a second DC output voltage connected in parallel with the first DC output voltage; control circuitry that selectively enables and disables the high power DC-DC converter responsive to load conditions; and an inrush current limiting circuit that includes: a resistor coupled in series between the one or more input stages and the bulk capacitor so as to limit an inrush current to the bulk capacitor; a relay responsive to the control circuitry that selectively bypasses the resistor under high load conditions once the bulk capacitor is charged; and a solid-state switching device responsive to the control circuitry that selectively bypasses the resistor under low load conditions once the bulk capacitor is charged.
Facts
- Company
- Apple (Apple Inc.)
- Official title
- Inrush current suppression for AC-DC power supplies
- Patent number
- US12732093B2
- Application number
- 18360347
- Filed
- Jul 27, 2023
- Granted
- Sep 8, 2026
- Inventors
- 5
- Claims
- 12
Classified under
H02M 1/32 Electricity & electronicsH02M 1/4208 Electricity & electronicsMore from Apple in Chips & hardware
- Apple patents glass chip base that uses light to move data Oct 8, 2026
- Apple patents radar that maps rooms using moving objects Sep 1, 2026
- Apple patents display method that reuses static images to save power Sep 1, 2026
- Apple patents stretchable OLED displays with sealed pixel islands Sep 8, 2026
- Apple patents method to fix color fringes in high-resolution displays Sep 8, 2026
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.