Battery/Charger Load Switch Approximates Ideal Diode

Abstract: Two circuits are described. The first uses external MOSFETs driven by the Power OK (POK) output of a Li-cell charger IC (MAX8814), to switch a load between battery and charging source without intervention from a microcontroller or system software. For charger ICs without a POK output (such as the MAX1507), the second circuit does the same switching using MOSFETs and a comparator (MAX920).
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Keywords: load switching, rechargeable battery-powered systems, Li+ battery chargers, power OK (POK) outputs

Feb 10, 2011
APPLICATION NOTE4840
Battery/Charger Load Switch Approximates Ideal Diode
By:Budge Ing
Hubert Bugajski

Abstract:Two circuits are described. The first uses external MOSFETs driven by the Power OK (POK) output of a Li-cell charger IC
(MAX8814), to switch a load between battery and charging source without intervention from a microcontroller or system software. For
charger ICs without a POK output (