Siemens SL55 - 6 Power Supply; Power Supply ASIC

Customer Care
V 1.0 Page 27of 52 ICM MP CCQ GRM
SL55
Company Confidential © Copyright Siemens AG
06/03
6 Power Supply
6.1 Power Supply ASIC
The power supply ASIC contains the following functions:
• Powerdown-Mode
• Sleep Mode
• Trickle Charge Mode
• Power on Reset
• Digital state machine to control switch on and supervise the µC with a watchdog
• Voltage regulator
• Low power voltage regulator
• Additional output ports
• Voltage supervision
• Temperature supervision with external and internal sensor
• Battery charge control
• TWI interface
• I
2C interface
• RC Oscillator
• Audio multiplexer
• Audio amplifier stereo/mono
• 18 bit Sigma/Delta DAC with Clock recovery
• Bandgap reference*
INFO:
* Bandgap reference
The p-n junction of a semiconductor has a bandgap-voltage. This bandgap-voltage is
almost independent of changes in the supply voltage and has a very low temperature
gradient. The bandgap-voltage is used as reference for the voltage regulators.
To reduce the power consumption of the ASIC and to ensure high efficiency of the power
management concept a DCDC Converter N361 for the Core (EGOLD+V3X Baseband
Chipset), Flash and SRAM supply is used. During this time all voltage regulators inside
the ASIC are switched off.
The DCDC converter N361 includes the following functions:
· PFM Mode for sleep mode of the Mobile Phone.
· PWM Mode for active mode of the Mobile Phone.
The mode change is controlled by the ASIC with the signal EN_DC_DOWN (
Pin J1) based
on the EGOLD+ signal VCXO_EN.