Electronic Components Datasheet Search |
|
BQ24401PW Datasheet(PDF) 8 Page - Texas Instruments |
|
|
BQ24401PW Datasheet(HTML) 8 Page - Texas Instruments |
8 / 27 page 200 160 180 140 120 100 80 60 40 20 4 3 2 1 2 4 6 8 10 50 100 150 200 250 R -k MTO W ShowsTolerance bq24401 SLUS497A – SEPTEMBER 2001 – REVISED MARCH 2010 www.ti.com disabled. When the voltage at the TS pin is lower than VTCO, the bq24401 terminates fast charge, moves to the charge suspended state, and turns off the LED. When VTS rises above VHTF, the bq24401 will resume charging in the trickle maintenance charge state, per Figure 2. In fast charge, when the voltage on the TS pin is higher than VLTF, the charger enters the battery conditioning state, as described in the previous section. Fast charge is resumed when VTS is less than VLTF. Rate of Temperature Rise The bq24401 uses a rate of temperature rise ( ΔT/Δt) scheme to terminate fast charge for NiCd and NiMH batteries. During fast charge, it samples the TS pin voltage every 8 seconds and compares it to the value measured 2 samples earlier. This feature terminates fast charge if this voltage declines at a rate of VCC/161 (V/min). Figure 4 shows a typical connection diagram. In preparation for sampling the TS pin voltage, the bq24401 briefly turns off most circuits (the MOD and RC pins will both go low) in order to get the cleanest possible, noise-free measurement. While the monitoring of the TS pin voltage is continuous, the sampling of the TS pin voltage with the internal ADC only occurs during fast charge. Top-Off and Pulse-Trickle Maintenance Charge Once constant-current fast charge has ended, the bq24401 measures the value of the CMTO capacitor and then proceeds to either top-off or trickle maintenance charge. Top-off is optional and may be desirable on batteries that have a tendency to terminate charge before reaching full capacity. To enable this option, the capacitance value of CMTO connected between the RC pin and VCC (see Figure 3) should be greater than 0.13µF, and the value of the resistor connected to this pin should be less than 250k Ω. To disable top-off, the capacitance value should be less than 0.07µF. The tolerance of the capacitor needs to be taken into account in component selection. Once top-off is started, the timer is reset and top-off proceeds until the timer expires, VMCV is reached, or there is a temperature fault. During top-off, current is delivered to the battery in pulses that occur each second. The fixed pulse width allows an average current of 1/16 of the fast charge current to be delivered to the battery every second. The LED is always off during top-off and trickle maintenance charge. During top-off, there are three different temperature faults that can occur. If VTS > VLTF, top-off is suspended, the timer is paused, and trickle charge is started. When VTS falls below VLTF, top-off is resumed. If VTS < VHTF, all charging stops, but the timer keeps counting. When VTS > VHTF, top-off is resumed, if there is still time remaining on the timer. If there is not time left, trickle maintenance charge is entered. If VTS < VTCO, all charging stops. Only trickle maintenance charge may resume after VTS > VHTF. Following top-off, the bq24401 trickle-charges the battery by enabling the MOD pin to charge at a rate of once every 1.0 second. The trickle pulse-width is user-selectable and is set by the value of the resistor RMTO, connected between the RC pin and VSS. Figure 5 shows the relationship between the trickle pulse-width and the value of RMTO. The typical tolerance of the pulsewidth below 150kΩ is ±10%. Figure 5. Relationship Between Trickle Pulse-Width and Value of RMTO 8 Submit Documentation Feedback Copyright © 2001–2010, Texas Instruments Incorporated Product Folder Link(s): bq24401 |
Similar Part No. - BQ24401PW |
|
Similar Description - BQ24401PW |
|
|
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 |