LG GS290 Service Manual page 30

GS290 Operational Description
SM-POWER is a further step on the successful E-Power product line with enhanced and optimized functionality.
SM-POWER features a baseband supply concept with a DC/DC step-down converter cascaded by two linear
regulators
–SM-POWER's DC/DC converter makes up to 40 % reduction of battery current for smart phone functions (e.g.
organizer functions, games, MP3 decoding) possible.
– SDBB has high efficiency up to 95% and also a power save mode.
– Memory Interface is directly supported by the SDBB
– SDBB can also act as main supply voltage for E-GOLD+ or S-GOLDlite baseband devices.
– For S-GOLD two linear regulators for DSP and Core are cascaded after the SDBB.
SM-POWER supports the standby power-down concept of S-GOLD by temporarily switching off the linear
regulator for the DSP during mobile standby whenever this subsystem is not used. In this phase the ARM
controller and most peripherals including parts of the on-chip SRAM are kept powered-up with power being
supplied by the other linear regulator.
SM-POWER includes a fully differential audio amplifier able to drive loads down to a nominal value of 8 Ohm for
usage in hands-free phones and for ringing
– 450 mW maximum output power
– adjustable gain
– mute switch SM-POWER also integrates a charging function for Li-Ion, Li-Polymer batteries
– click and pop -protection SM-POWER also integrates a charging function for Li-Ion, Li-Polymer batteries
– Precharge current source with two current levels
– Constant current / constant voltage charging with 3 different termination voltages
– Programable charge current limitation for use with different batteries
– Freely programable pulse charging to reduce the thermal power dissipation in the constant voltage
charging phase
– Top-off charge current sensing SM-POWER completes the USB interface of S-GOLD
– Regulated voltage for S-GOLD USB interface including reverse current and overvoltage protection
– Switch to supply USB pull-up resistor
– Mini-host pull down resistor functionality
– Charge pump with internal switching capacitor for USB host VBUS supply voltage SM-POWER fully supports
LED and Vibra Motor functionality
– no external components needed
– driver for backlight LEDs adjustable in steps up to 140mA and with soft turn on and off by PWM dimming
– two driver outputs for single LEDs for precharge indication and signaling with i.e. change of colour
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