Electronic Components Datasheet Search |
|
ISL6294IRZ-T Datasheet(PDF) 7 Page - Intersil Corporation |
|
ISL6294IRZ-T Datasheet(HTML) 7 Page - Intersil Corporation |
7 / 9 page 7 FN9174.4 July 9, 2007 Applications Information Input Capacitor Selection The input capacitor is required to suppress the power supply transient response during transitions. Mainly this capacitor is selected to avoid oscillation during the start up when the input supply is passing the POR threshold and the VIN - BAT comparator offset voltage. When the battery voltage is above the POR threshold, the VIN - VBAT offset voltage dominates the hysteresis value. Typically, a 1µF X5R ceramic capacitor should be sufficient to suppress the power supply noise. Output Capacitor Selection The criteria for selecting the output capacitor is to maintain the stability of the charger as well as to bypass any transient load current. The minimum capacitance is a 1µF X5R ceramic capacitor. The actual capacitance connected to the output is dependent on the actual application requirement. Charge Current Limit The actual charge current in the CC mode is limited by several factors in addition to the set IREF. Figure 1 shows three limits for the charge current in the CC mode. The charge current is limited by the on resistance of the pass element (power P-Channel MOSFET) if the input and the output voltage are too close to each other. The solid curve shows a typical case when the battery voltage is 4.0V and the charge current is set to 700mA. The non-linearity on the rON-limited region is due to the increased resistance at higher die temperature. If the battery voltage increases to higher than 4.0V, the entire curve moves towards right side. As the input voltage increases, the charge current may be reduced due to the thermal foldback function. The limit caused by the thermal limit is dependent on the thermal impedance. As the thermal impedance increases, the thermal-limited curve moves towards left, as shown in Figure 1. Layout Guidance The ISL6294 uses a thermally-enhanced DFN package that has an exposed thermal pad at the bottom side of the package. The layout should connect as much as possible to copper on the exposed pad. Typically the component layer is more effective in dissipating heat. The thermal impedance can be further reduced by using other layers of copper connecting to the exposed pad through a thermal via array. Each thermal via is recommended to have 0.3mm diameter and 1mm distance from other thermal vias. Input Power Sources The input power source is typically a well-regulated wall cube with 1-meter length wire or a USB port. The input voltage ranges from 4.25V to 6.5V under full-load and unloaded conditions. The ISL6294 can withstand up to 28V on the input without damaging the IC. If the input voltage is higher than typically 6.8V, the charger stops charging. 6.5 4.0 700 INPUT VOLTAGE (V) 4.5 5.0 5.5 6.0 θ JA or TA INCREASES VBAT INCREASES RIREF INCREASES rON LIMITED THERMAL LIMITED ISL6294 FIGURE 1. CHARGE CURRENT LIMITS IN THE CC MODE |
Similar Part No. - ISL6294IRZ-T |
|
Similar Description - ISL6294IRZ-T |
|
|
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 |