Low-power system clock calibration based on a high-accuracy reference clock
US9079040B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2014 |
| Grant date | Jul 14, 2015 |
| Priority date | — |
| Expiry date | Aug 29, 2034 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N1/37276
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
Various techniques are described for periodically performing a calibration routine to calibrate a low-power system clock within an implantable medical device (IMD) based on a high accuracy reference clock also included in the IMD. The system clock is powered continuously, and the reference clock is only powered on during the calibration routine. The techniques include determining a clock error of the system clock based on a difference between frequencies of the system clock and the reference clock over a fixed number of clock cycles, and adjusting a trim value of the system clock to compensate for the clock error. Calibrating the system clock with a delta-sigma loop, for example, reduces the clock error over time. This allows accurate adjustment of the system clock to compensate for errors due to trim resolution, circuit noise and temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.