What is the precharge function in sdram?

[ahgu]

I don't understand the precharge? I know it is used to closed a row in bank, wrt to the active? But what is its purpose in the low-level electronics?

Also what is its usage? do I have to do everytime I do a read in a row and want to read the next row, I have to precharge the first row first and then move to the second row? or can I just ignore it? only do it in the initialization.

thanks
Ahgu

 

[maskrom]

dram precharge

Hello ahgu:
precharge is avery importment step before you read another row in DRAM and SRAM. In DRAM, precharge will turn off active word line and precharge bit line pairs to ready state. If you ignore this procedure, bl and blb will have some voltage difference. After charge sharing, maybe the voltage difference will not be large enough for sense amplifier to sense. That will be fail.

 

[naresh850]

precharge sdram

thnks muakrom

if u have more info in (auto refresh &self refresh ) that then can send im on
naresh850 at gmail

 

[Iouri]

precharge dram

**broken link removed**

 

[tronix]

precharge in sdram

SDRAM basically uses Pseudo NMOS logic in which there will be static power dissipation when the particular row is not selected . To avoid this all rows are precharged to Vdd and rthe logic implemented becomes Dynamic Logic basically.

Refer to Semiconductor Text (Sedra for ex.)

 

[funster]

what is precharge in sdram

precharge's function is to write a whole row data into SDRAM memory bank.

if you open a new row without precharge a opened row,

the data in the previous row will lost.

best regards

I don't understand the precharge? I know it is used to closed a row in bank, wrt to the active? But what is its purpose in the low-level electronics?

Also what is its usage? do I have to do everytime I do a read in a row and want to read the next row, I have to precharge the first row first and then move to the second row? or can I just ignore it? only do it in the initialization.

thanks
Ahgu