Philips S1D13505 Manual De Usuario

Page 3

Vancouver Design Center

Power Consumption

S1D13505

Issue Date: 01/02/05 

X23A-G-006-03

S1D13505 power consumption is affected by many system design variables.

• Input clock frequency (CLKI): the CLKI frequency determines the LCD frame-rate, CPU perfor-

mance to memory, and other functions – the higher the input clock frequency, the higher the 
frame-rate, performance and power consumption.  

• CPU interface: the S1D13505 current consumption depends on the BUSCLK frequency, data 

width, number of toggling pins, and other factors – the higher the BUSCLK, the higher the CPU 
performance and power consumption.

• V

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 voltage level: the voltage level affects power consumption – the higher the voltage, the 

higher the consumption.

• Display mode: the resolution and color depth affect power consumption – the higher the

resolution/color depth, the higher the consumption.

• Internal CLK divide: internal registers allow the input clock to be divided before going to the 

internal logic blocks – the higher the divide, the lower the power consumption.

There are two power save modes in the S1D13505: Software and Hardware SUSPEND. The power 
consumption of these modes is affected by various system design variables.

• DRAM refresh mode (CBR or self-refresh): self-refresh capable DRAM allows the S1D13505 to 

disable the internal memory clock thereby saving power.

• CPU bus state during SUSPEND: the state of the CPU bus signals during SUSPEND has a 

substantial effect on power consumption. An inactive bus (e.g. BUSCLK = low, Addr = low etc.) 
reduces overall system power consumption.

• CLKI state during SUSPEND: disabling the CLKI during SUSPEND has substantial power 

savings.