Abstract: A wearable CO2 monitor and stale air dosimeter comprising a power supply with rechargeable battery and battery charger, an accurate CO2 sensor, a fast-reacting CO2 sensor, programmable control circuitry, and a user interface for presenting results and indications. The accurate CO2 sensor provides CO2 levels which are used to compute staleness levels and further accumulated as a staleness dose. The fast-reacting CO2 sensor alerts the user to changes in CO2 levels and allows the accurate CO2 sensor to be powered down during periods when CO2 levels are stable.

Abstract: A circuit for converting DC to AC power or AC to DC power comprises a storage capacitor, boost and buck inductors and switching elements. The switches are controlled to steer current to and from the storage capacitor to cancel DC input ripple or to provide near unity power factor AC input. The capacitor is alternately charged to high positive or negative voltages with an average DC bias near zero. The circuit is configured to deliver high-efficiency power in applications including industrial equipment, home appliances, mobility devices and electric vehicle applications.