Nokia NSE–3 SERIES Service Manual

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Nokia NSE–3 SERIES Service Manual Manual pdf 24 page image

PAMSTechnical DocumentationNSE–3System ModuleOriginal 11/97Page 3 – 18Battery chargingThe electrical specifications give the idle voltages produced by the ac-ceptable chargers at the DC connector input. The absolute maximum in-put voltage is 30V due to the transient suppressor that is protecting thecharger input. At phone end there is no difference between a plug–incharger or a desktop charger. The DC–jack pins and bottom connectorcharging pads are connected together inside the phone.VINCHAPS10k1nPWMVBATGNDCCONTCHRG_CTRLL_GNDCHARGERPWM_OUTTRANSCEIVER0R22VCHARICHAR100k22k1u2A30VVCHVOUTRSENSEGNDNOT INACP–7CCONTINTMADLIMMADStartup ChargingWhen a charger is connected, the CHAPS is supplying a startup currentminimum of 130mA to the phone. The startup current provides initialcharging to a phone with an empty battery. Startup circuit charges thebattery until the battery voltage level is reaches 3.0V (+/– 0.1V) and theCCONT releases the PURX reset signal and program execution starts.Charging mode is changed from startup charging to PWM charging that iscontrolled by the MCU software. If the battery voltage reaches 3.55V(3.75V maximum) before the program has taken control over the charg-ing, the startup current is switched off. The startup current is switched onagain when the battery voltage is sunken 100mV (nominal).Parameter Symbol Min Typ Max UnitVOUT Start– up mode cutoff limit Vstart 3.45 3.55 3.75 VVOUT Start– up mode hysteresisNOTE: Cout = 4.7 uFVstarthys 80 100 200 mVStart–up regulator output currentVOUT = 0V ... VstartIstart 130 165 200 mA