Electronic Components Datasheet Search |
|
LTC4061EDD Datasheet(PDF) 10 Page - Linear Technology |
|
LTC4061EDD Datasheet(HTML) 10 Page - Linear Technology |
10 / 20 page LTC4061 0 4061fd operaTion UndervoltageLockout(UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshold (3.8V). The UVLO circuit has a built-in hysteresis of 200mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in shutdown mode if VCC falls to less than 45mV above the battery voltage. Hysteresis of 145mV prevents the charger from cycling in and out of shutdown. ManualShutdown At any point in the charge cycle, the charger can be put into shutdown mode by pulling the EN pin high. This reduces the supply current to less than 50µA and the battery drain current of the charger to less than 2µA. A new charge cycle can be initiated by floating the EN pin or pulling it low. If shutdown is not required, leaving the pin disconnected continuously enables the circuit. Trickle-ChargeandDefectiveBatteryDetection When the BAT pin voltage is below the 2.9V trickle charge threshold (VTRIKL),thechargerreducesthechargecurrent to 10% of the programmed value. If the battery remains in trickle charge for more than 25% of the total programmed chargetime,thechargerstopschargingandentersaFAULT state,indicatingthatthebatteryisdefective1.TheLTC4061 indicates the FAULT state by driving the CHRG open-drain outputwithasquarewave.Thedutycycleofthisoscillation is 50% and the frequency is set by CTIMER: f µF C Hz CHRG TIMER = 0 1 6 . • ALEDdrivenbytheCHRGoutputexhibitsapulsingpattern, indicating to the user that the battery needs replacing. To exit the FAULT state, the charger must be restarted either by toggling the EN input or removing and reapplying power to VCC. ChargeStatusOutput(CHRG) Thechargestatusindicatorpinhasthreestates:pull-down, pulseat1.5Hzor6Hzandhighimpedance.Inthepull-down state, an NMOS transistor pulls down on the CHRG pin capable of sinking up to 10mA. A pull-down state indicates that the LTC4061 is charging a battery and the charge cur- rent is greater than IDETECT (which is set by the external component RDET). A high impedance state indicates that the charge current has dropped below IDETECT. In the case where the IDET pin is left unconnected (RDET = ∞, IDETECT = 0), a high impedance state on CHRG indicates that the LTC4061 is not charging. SmartPulsingErrorFeature LTC4061 has two different pulsing states at CHRG pull- down pin: 1. 6Hz (50% duty cycle) due to defective battery detection (see Trickle-Charge and Defective Battery Detection section); 2. 1.5Hz (25% duty cycle if in time termination, 50% duty cycle if in charge current or user termination) due to NTC out-of-temperature condition. NTCThermistor(NTC) The temperature of the battery is measured by placing a negative temperature coefficient (NTC) thermistor close to the battery pack. The NTC circuitry is shown in Figure 1. To use this feature, connect the NTC thermistor, RNTC, between the NTC pin and ground and a resistor, RNOM, from the NTC pin to VCC. RNOM should be a 1% resistor with a value equal to the value of the chosen NTC thermistor at 25°C (this value is 100kΩ for a Vishay NTH- S0603N01N1003Jthermistor).TheLTC4061goesintohold mode when the resistance, RHOT, of the NTC thermistor drops to 0.53 times the value of RNOM or approximately 53kΩ, which corresponds to approximately 40°C. Hold mode freezes the timer and stops the charge cycle until the thermistor indicates a return to a valid temperature. As the temperature drops, the resistance of the NTC thermistor rises. The LTC4061 is designed to go into hold mode when the value of the NTC thermistor increases to 3.26 times the value of RNOM This resistance is RCOLD. For a Vishay NTHS0603N01N1003J thermistor, this value is 326kΩ, whichcorrespondstoapproximately0°C.Thehotandcold comparators each have approximately 2°C of hysteresis to prevent oscillation about the trip point. Grounding the NTC pin disables the NTC function. For more details refer to the Application Information section. 1 The Defective Battery Detection feature is only available when time termination is being used. |
Similar Part No. - LTC4061EDD |
|
Similar Description - LTC4061EDD |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |