RF_beginner
Member level 4
limited current circuit
hi,I am designing a PCMCI EDGE wireless card used in notebook computer .and now i have to stop advancing for a problem. you know , notebook computer 's PCMCIA interface is power limited,which is limited in 3.3W output. but when the EDGE card works in GSM pcl 5 ,it needs at least 34dBm (32.5+1.5 IL),or 2.5W, but considering the whole system's demand ,we now only have 1.8W to it, so we adapt one big capacitance (100mF) to compensate .but the result is not as we imagine ,the voltage (we use 3.3v ) drops 500mv still( this lead the system's unsteable) or to say,the capacitance doesn't work!!, why? the power line we supply is :3.3v(notebook computer)-->DC/DC (TPS61030 TI, 3.8v)--->LDO( R1173D001D RICHON 3.6V)--->PA
and now ,i'd like to design a current limited circuit between DC/DC and PA to let capacitance work ,how could i do? or does anybody here know how to use LDO ,for example R1173D001D,realize this function ??
thanks advance!!
hi,I am designing a PCMCI EDGE wireless card used in notebook computer .and now i have to stop advancing for a problem. you know , notebook computer 's PCMCIA interface is power limited,which is limited in 3.3W output. but when the EDGE card works in GSM pcl 5 ,it needs at least 34dBm (32.5+1.5 IL),or 2.5W, but considering the whole system's demand ,we now only have 1.8W to it, so we adapt one big capacitance (100mF) to compensate .but the result is not as we imagine ,the voltage (we use 3.3v ) drops 500mv still( this lead the system's unsteable) or to say,the capacitance doesn't work!!, why? the power line we supply is :3.3v(notebook computer)-->DC/DC (TPS61030 TI, 3.8v)--->LDO( R1173D001D RICHON 3.6V)--->PA
and now ,i'd like to design a current limited circuit between DC/DC and PA to let capacitance work ,how could i do? or does anybody here know how to use LDO ,for example R1173D001D,realize this function ??
thanks advance!!