* Bob: From last time, concluded:
1) Range of 40 - 200 beats / min with resolution of 1 beat. 2)
Measurements averaged over 7 pulses, and 3) because some people's
heart stops every day (it skips a beat), assume it occurs on the
average 1/12 hrs, range of 0-10 beats. Chris: The causes are
many, but for us, the relevant issue is how to we distinguish
between a skipped or missed beat and a long beat. We looked at
A&D's website for their TM2430 specifications. Remaining questions
are: 1) sampling frequency to meet these requirements.
* Larry Beaty:
* Chris: Use cases.
* Dick: Power Mgt.
Battery Power Management by Dick Schwarz
Battery-based power management subsystem include:
* Battery
* Power Mgt HW
* System SW
* Application SW
HW Design Objectives include:
* Achieving performance and time-between charge goals, while minimizing
battery size and weight.
* Providing appropriate output voltage regulation over a wide
input range.
* Decreasing pc-board space.
* Minimizing heat dissipation,.
* Optimizing circuit layout to prevent electromagnetic interference
(EMI).
* Maximizing reliability.
Battery Selection
Primary batteries:
* Alkaline and conventional lithium metal cells.
* Considered to be dispensable items.
* Caution - lithium metal cells are flammable,.
Popular rechargeable batteries:
* Nickel Cadmium (NiCad) - long life, high discharge rate, economical
price.
* Nickel-Metal Hydride (NiMH) - higher energy NiCad at expense
of reducer cycle life.
* Lithium ion (Li-ion) - high energy density and lightweight.
* Lithium Polymer (Li-Pol) - chemistry similar to the Li-Ion in
terms of energy density, safer to use and has better package flexibility.
Battery Mgt Components
Main battery mgt components:
* Charge Mgt - safely charge rechargeable batteries, maximize
capacity, and minimize charge time.
* Battery Fuel Gauging - allows system to acquire the exact state
of battery charge.
* Battery Protection prevents overcharge or over discharge conditions.
* Cell Selection/Balancing - used in multiple battery systems.
* Battery Identification (Authentication) - electrical identification
prevents physical counterfeit.
Hardware Capabilities
* Intersil:
* Maxim:
* TI:
* Analog Devices
* Freescale
Power Mgt Software
* System Software
- Retrieve system power information
- Control activities based on system power status
- API and messages.
* Application software
- Reduce performance/quality of features.
- Turn off background activities.
This page is maintained by Ellis S Nolley. It was last updated on 24 August 2008.
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