Panasonic EB-GD90 Technical Manual

Also see for EB-GD90: Operating instructions

Contents

http://cxema.ruPOWER SUPPLIESMCUK990801G8 Section 9 Issue 1Technical Guide – 33 – Revision 09 POWER SUPPLIES9.1 IntroductionThis section describes the Power Supply Unit (PSU) used on the GD90 Main PCB and the method by which it is controlled.The Battery life during GSM1800 operation benefits from lower transmit power and higher PA efficiency and is therefore moreefficient than when operating in GSM900.This section has detailed information on:1. An overview of the circuit functionality.2. Powering-up the phone.3. Powering-down the phone.4. Power management.9.2 OverviewThe logic circuit uses three separate power supplies as follows:1. 2.8 Volts supply is used for the main power supply, 2V8 provides power to the digital part of the baseband circuit (Gemini,Memory and LCD). A2V8 is used to power the analogue part of the baseband circuit (Vega and voice memo).2. 1.8 Volts is provided to power internal blocks within the Gemini (ARM, DSP, ASIC).3. 5.0 Volts (SIM_PWR) is provided to power the SIM and the SIM interface. This is enabled only when it is necessary tocommunicate with the SIM.The RF circuit uses three power supplies each provided by a separate 2.8 Volt regulator within U401. They are VSRF andVS_VCO which are present when the LO_EN signal is present, and VS_VXCO which are present with the signal RF_ON. Thepower amplifiers are powered directly from the battery VBAT.9.3 Power-upThe power-up procedure has two phases. If an initial check to see if the battery is in good condition is successful, the secondphase determines the source of the power-up request, key press, external power, accessory, etc. and acts accordingly.The phone can be defined as powered-on whenever the linear regulators are active. It is not always obvious to the user thatthe phone is powered-on as it may be in one of four modes:9.3.1 Battery ConditionThe CPU must check the battery condition before deciding to power-up. The CPU can measure battery voltage andtemperature. If the battery temperature measurement is invalid, a non-standard battery has been fitted, the battery is missingor the whole phone is operating far outside its specified temperature range, the phone is not powered-up. The CPU will regularlymonitor the battery condition while the phone is on.If EXT_PWR is present, the regulators will be forced on and the CPU will be unable to deactivate them. If the CPU wants topower-down, all it can do is to enter sleep mode.Mode DescriptionSleep In this mode the CPU has been prevented from deactivating the linear regulators by EXT_PWR.There is no CPU activity.Charge The CPU is alive but may perform only battery charging functions and monitor the power key.Restricted LEDs light, beeps, can charge battery etc. but it is not permitted to use the radio.Active The mobile is fully functional; LEDs light, beeps, search for network etc.Battery Voltage (V) Temp. reading nEXT_PWR ResultX (don't care) invalid 0.5 V Power-down (battery fault)X invalid 1.2 V Sleep (battery fault)<3.0 X <0.5 V Power-down (low battery)<3.5 valid 1.2 V LOW>3.5 valid X OK