Temperature compensation monitoring circuit for a battery pack charging apparatus
US5744939A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 5, 1996 |
| Grant date | Apr 28, 1998 |
| Priority date | — |
| Expiry date | Sep 5, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E60/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A monitoring circuit for a Li-Ion battery pack charging apparatus is disclosed. The monitoring circuit modifies charging time for a Li-Ion battery pack inserted in the charging apparatus to compensate for temperature effects on the charging current input to the battery pack. In one embodiment of the monitoring circuit, a comparator is utilized to compare a voltage across the battery pack, V.sub.charge, to a set point voltage value, V.sub.sp. The set point voltage value, V.sub.sp, is taken off a temperature sensor circuit comprising a voltage divider circuit. The voltage divider circuit includes at least one thermistor in a ground connected leg of the divider. In a second embodiment of the monitoring circuit of the present invention, a differential amplifier is coupled to opposite ends of a low resistance sensor resistor. The sensor resistor is coupled between charging circuitry and the Li-Ion battery pack to be charged. The voltage differential across the resistor, V.sub.sensor, is amplified by a gain of the differential amplifier. A gain adjusted differential voltage, V.sub.gsensor, is compared by a microprocessor to a set point voltage value, V.sub.sp. The set point voltage value…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.