In normal operation the baseband is powered from the phone's battery. The battery consists of one Lithium-cell. There is also a possibility to use batteries consisting of three Nickel- cells. An external charger can be used for recharging the battery and supplying power to the phone. The charger can be either so called fast charger, which can deliver supply current up to 850 mA or a standard charger that can deliver around 300 mA.
Battery voltage VBAT is connected to CCONT which regulates all the supply voltages VBB, VR1-VR7, V2V, VR1_SW, VSIM and V5V. VR7 is divided into VR7 and VR7_bias. VR7_bias is for RF, because PA is heating and this reduces the heat. CCONT enables automatically VR1, VBB, V2V_core, VR6 and Vref in power-up.
VBB is used as baseband power supply for all digital parts, and it is constantly on whenever the phone is powered up. There is also another Baseband voltage, V2V, which is reserved for later version of MAD circuit. V2V will be used as a lower core voltage for MAD internal parts, by supplying it to specific MAD core voltage pins. Until that time, VBB will be used for all MAD pins. VSIM can be used as programming voltage for the Flash memory, if re-flashing is needed after initial flash programming in production. V5V is used for RF parts only.
VR1 is used for the VCXO supply. VR1_SW is derived from VR1 inside CCONT, and is actually the same voltage, but can be separately switched
System Module US4RSM Technical Documentation on and off. This VR1_SW is used as bias voltage for microphone, during talk modes. Voltage VR6 is used in COBBA for analog parts and also in RF parts. RFCEN signal to CCONT controls both the VR1 and VR6 regulators; they can be switched off in sleep modes, during standby.
CCONT regulators are controlled either through SIO from MAD or timing sensitive regulators are controlled directly to their control pins. These two control methods form a logical OR-function, i.e. the regulator is enabled when either of the controls is active. Most of the regulators can be individually controlled.
CHAPS connects the charger voltage (VCHAR) to battery. MCU of MAD controls the charging through CCONT. MAD sets the parameters to PWM-generator in CCONT and PWM-output controls the charging voltage in charger.
When battery voltage is under 3.0V, CHAPS controls independently the charging current to battery.
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