Electronic Components Datasheet Search |
|
LTC1732-4 Datasheet(PDF) 7 Page - Linear Technology |
|
LTC1732-4 Datasheet(HTML) 7 Page - Linear Technology |
7 / 12 page 7 LTC1732-4/LTC1732-4.2 The LTC1732 is a linear battery charger controller. The charge current is programmed by the combination of a program resistor (RPROG) from the PROG pin to ground and a sense resistor (RSENSE) between the VCC and SENSE pins. RPROG sets a program current through an internal trimmed 800 Ω resistor setting up a voltage drop from VCC to the input of the current amplifier (CA). The current amplifier servos the gate of the external P-channel MOSFET to force the same voltage drop across RSENSE which sets the charge current. When the potential at the BAT pin approaches the preset float voltage, the voltage amplifier (VA) will start sinking current which shrinks the voltage drop across RSENSE, thus reducing the charge current. Charging begins when the potential on the VCC pin rises above the UVLO level and a program resistor is connected from the PROG pin to ground. At the beginning of the charge cycle, if the battery voltage is below 2.457V, the charger goes into trickle charge mode. The trickle charge current is 10% of the full-scale current. If the cell voltage stays low for one quarter of the total charge time, the charge sequence will terminate. The charger goes into the fast charge constant-current mode after the voltage on the BAT pin rises above 2.457V. In constant-current mode, the charge current is set by the combination of RSENSE and RPROG. When the battery approaches the final float voltage, the charge current will begin to decrease. When the current drops to 10% of the full-scale charge current, an internal comparator will turn off the pull-down N-channel MOSFET at the CHRG pin and connect a weak current source to ground to indicate an end-of-charge (C/10) condition. An external capacitor on the TIMER pin sets the total charge time. After a time-out occurs, the charge cycle is terminated and the CHRG pin is forced to a high imped- ance state. To restart the charge cycle, simply remove the input voltage and reapply it, or float the PROG pin momen- tarily. For batteries like lithium-ion that require accurate final float potential, the internal 2.457V reference, voltage am- plifier and the resistor divider provide regulation with ±1% (max) accuracy. For NiMH and NiCd batteries, the LTC1732 can function as a current source by pulling the TIMER pin to VCC. When in the constant-current only mode, the voltage amplifier, timer, C/10 comparator and the trickle charge function are all disabled. The charger can be shut down by floating the PROG pin (ICC = 1mA). An internal current source will pull this pin high and clamp it at 3.5V. When the input voltage is not present, the charger goes into a sleep mode, dropping ICC to 7µA. This greatly reduces the current drain on the battery and increases the standby time. OPERATIO |
Similar Part No. - LTC1732-4_15 |
|
Similar Description - LTC1732-4_15 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List 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 |