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SED1354 Datasheet, PDF (327/472 Pages) Epson Company – Color Graphics LCD/CRT Controller | |||
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Epson Research and Development
Vancouver Design Center
Page 3
1 SED1354 Power Consumption
SED1354 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 â the higher the input clock frequency, the higher the
frame-rate, performance and power consumption.
⢠CPU interface: the SED1354 IO VDD current consumption depends on the BUSCLK frequency,
data width, number of toggling pins, and other factors â the higher the BUSCLK, the higher the
CPU performance and power consumption.
⢠Core VDD, IO VDD voltage levels: the voltage levels of the two independent VDD groups (Core,
IO) affect power consumption â the higher the voltage, the higher the consumption.
⢠Display mode: the resolution and color depth affect power consumption â 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 â the higher the divide, the lower the power consumption.
There are two power save modes in the SED1354: Software and Hardware SUSPEND. The power
consumption of these modes is also affected by various system design variables.
⢠DRAM refresh mode, CBR or self-refresh: self-refresh capable DRAM allows the SED1354 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.
Power Consumption
Issue Date: 98/10/29
SED1354
X19A-G-006-03
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