Motor de Búsqueda de Datasheet de Componentes Electrónicos |
|
SS8000GQTR Datasheet(PDF) 9 Page - Silicon Standard Corp. |
|
SS8000GQTR Datasheet(HTML) 9 Page - Silicon Standard Corp. |
9 / 14 page www.SiliconStandard.com 9 of 14 SS8000G APPLICATION INFORMATION (cont.) Power Sequence and Protection Logic The SS8000 handles the power-ON and -OFF of the handset. It is possible to start the power-on sequence in three different ways: n Pulling PWRKEY low n Pulling PWRBB high n CHRIN exceeds Chr_Det threshold Pulling PWRKEY low is the normal way of turning on the handset. This will turn on Vcore, Vio, Vm LDOs as long as the PWRKEY is held low. The Vtcxo and Va LDOs are turned on when SRCLKEN is high. The microproc- essor then starts and pulls PWRBB high after which the PWRKEY can be released. Pulling PWRBB high will also turn on the handset. This is the case when the alarm in the RTC expires. Applying an external supply on CHRIN will also turn the handset on. If the SS8000 is in the UVLO state, ap- plying the adapter will not start up the LDOs. Table 1 shows states of the handset and the LDOs Table 1. States of Mobile Handset and LDO Phone State Chr_on -UV PWRBB (–PWRKEY) SRCLKEN Vrtc Vd,Vio,Vm Va, Vtcxo No Battery or Vbat < 2.5V X L X X Off Off Off 2.5V < Vbat < 3.2V L L X X On Off Off Pre-Charging H L X X On Off Off Charger-on H H X X On On On Switched off L H L X On Off Off Stand-by L H H L On Off On Active L H H H On On On Undervoltage Lockout (UVLO) The UVLO function in the SS8000 prevents startup when initial voltage of the main battery is below the 3.2V threshold. When the battery voltage is greater than 3.2V, the UVLO comparator trips and the threshold is reduced to 3.0V. This allows the handset to start normally until the battery decays to below 3.0V. Once the SS8000 enters a UVLO state, it draws very low quiescent current, typically 30µA. The RTC LDO is still running until the DDLO disables it. In this mode the SS8000 draws 5µA of quiescent current. Deep Discharge Lockout (DDLO) The DDLO in the SS8000 has two functions: l To turn off the Vrtc LDO. l To shut down the handset when the software fails to turn off the phone when the battery drops below 3.0V. The DDLO will shut down the handset when the bat- tery falls below 2.5 V to prevent further discharge and damage to the cells. Reset The SS8000 contains a reset circuit that is active at both power-up and power-down. The RESET pin is held low at initial power-up, and the reset delay timer is started. The delay is set by an external capacitor on RSTCAP: RSTCAP RESET C nF ms 2 t × = (1) At power-off, RESET will be kept low. Over-temperature Protection If the die temperature of the SS8000 exceeds 165°C, the SS8000 will disable all the LDOs except the RTC LDO. Once the over-temperature state is resolved, a new power-on sequence is required to enable the LDOs. Battery Charger The SS8000 battery charger can be used with Li-ion and NiMH batteries. The BATUSE pin can set SS8000 to fit the battery type. BATUSE is set low when a Li-ion battery is used, and set high when a NiMH battery is used. The SS8000 charges the battery in three phases: pre-charging, constant current mode charging, and con- stant voltage mode charging. Figure 2 shows the flow chart of charger behavior. The circuitry of the SS8000 combines a PMOS transistor, diode, current-sense re- sistor externally to form a simple and low cost linear charger shown in Figure 3. The SS8000 provides a pulsed top-off charging algorithm through the CHRCNTL pin from the baseband chipset. 12/06/2004 Rev.2.10 |
Número de pieza similar - SS8000GQTR |
|
Descripción similar - SS8000GQTR |
|
|
Enlace URL |
Política de Privacidad |
ALLDATASHEET.ES |
¿ALLDATASHEET es útil para Ud.? [ DONATE ] |
Todo acerca de Alldatasheet | Publicidad | Contáctenos | Política de Privacidad | Intercambio de Enlaces | Lista de Fabricantes All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |