US 7969231

Here is a concise summary of US patent 7969231:

US Patent 7969231 Summary

• Title: Internal voltage generating circuit
• Assignee: The current assignee is Advanced Memory Technologies LLC. The original assignee was Panasonic Corp.
• Inventors: Seiji Yamahira.
• Filing Date: July 2, 2009.
• Issue Date: June 28, 2011.
• Abstract: The patent describes an internal voltage generating circuit where an output terminal of a first boost circuit is connected to a second boost circuit. After the second boost circuit starts up, its boost clock frequency is reduced. This design reduces the startup time for the second boost circuit and increases the current supply capability of the first boost circuit once the second is running. The goal is to stably supply output voltages from both boost circuits without instantaneous changes in the first boost circuit's output voltage when the second boost circuit is active.

Independent Claims Overview:

• Claim 1: This claim describes an internal voltage generating circuit comprising a first boost circuit (between a first voltage and a first terminal), a second boost circuit (between the first terminal and a second terminal), a frequency dividing circuit (to divide a first clock signal for the first boost circuit to generate a second clock signal), and a buffer circuit (to select and supply either the first or second clock signal to the second boost circuit).
• Claim 3: This claim outlines an internal voltage generating circuit featuring a first charge pump circuit (generating a second voltage from a first voltage), a second charge pump circuit (generating a third voltage from the second voltage), a frequency dividing circuit (to generate a second clock signal from a first clock signal), and a buffer circuit (to select either the first or second clock signal to generate a third clock signal). This third clock signal is then supplied to the second charge pump circuit.
• Claim 6: This claim details an internal voltage generating circuit with a first charge pump circuit (generating a second voltage from a first voltage) and a second charge pump circuit (generating a third voltage from the second voltage). The frequency of the clock signal supplied to the second charge pump circuit is changed based on a control signal, specifically by dividing an original frequency.
• Claim 7: This claim describes an internal voltage generating circuit that includes a first charge pump circuit (generating a second voltage from a first voltage) and a second charge pump circuit (generating a third voltage from the second voltage). In this circuit, the duration of the high state of the clock signal supplied to the second charge pump circuit is changed according to a control signal.

Legal Status and Litigation:
The patent US7969231 is currently active and is set to expire on July 24, 2029.

According to the Google Patents record, the patent family has litigation. This includes:

• A PTAB case, IPR2025-01451, which was filed but not instituted (procedural).
• A US case filed in the Texas Western District Court (case number 1:25-cv-01036).
• A US case filed in the Texas Eastern District Court (case number 2:24-cv-01078).
• A "First worldwide family litigation" was also filed.

Additionally, a disclaimer was filed for claims 6-8 of said patent with an effective date of December 1, 2025, on March 24, 2026.

A review of the CAFC scheduled cases for May 2026 did not explicitly list US7969231. However, it's possible related litigation could be under a different case name or number. I cannot definitively confirm the absence of all CAFC dockets for 2026 without directly searching the CAFC database by patent number, which is not directly supported by the current tools for all types of queries.