• Patent Title: Variable refresh rate control using PWM-aligned frame periods
  • Application No.: US17786961
    Application Date: 2020-03-31
  • Publication No.: US11948520B2
    Publication Date: 2024-04-02
  • Inventor: Sang Young YounSun-il ChangWonjae ChoiSangmoo Choi
  • Applicant: GOOGLE LLC
  • Applicant Address: US CA Mountain View
  • Assignee: GOOGLE LLC
  • Current Assignee: GOOGLE LLC
  • Current Assignee Address: US CA Mountain View
  • International Application: PCT/US2020/025980 2020.03.31
  • International Announcement: WO2021/201844A 2021.10.07
  • Date entered country: 2022-06-17
  • Main IPC: G09G3/34
  • IPC: G09G3/34
Variable refresh rate control using PWM-aligned frame periods
Abstract:
PWM-frame rate misalignment is mitigated through implementation of a discrete variable refresh rate (VRR) scheme. A target frame rate is limited to a frame rate selected from only those frame rates that facilitate alignment of each frame period to a specified edge of a PWM cycle of a brightness control signal of a display panel. This alignment results in each frame period at the selected frame rate starting at a same point in a corresponding PWM cycle and ending at a same point in a corresponding PWM cycle to help ensure a constant effective duty cycle across each successive frame period, which in turn mitigates perception of flicker that otherwise would arise. Further, the discrete VRR scheme can employ a compensation mode for compensating for the delay in rendering or otherwise obtaining a frame for display so as to maintain a consistent duty cycle in the brightness control signal.
Public/Granted literature
Information query
Patent Agency Ranking
0/0