Electronic Components Datasheet Search |
|
ISL6594DCBZ Datasheet(PDF) 9 Page - Intersil Corporation |
|
ISL6594DCBZ Datasheet(HTML) 9 Page - Intersil Corporation |
9 / 11 page 9 FN9282.0 March 30, 2006 extended copper plane, and buried planes for heat spreading allows the IC to achieve its full thermal potential. Upper MOSFET Self Turn-On Effects At Start-up Should the driver have insufficient bias voltage applied, its outputs are floating. If the input bus is energized at a high dV/dt rate while the driver outputs are floating, because of self-coupling via the internal CGD of the MOSFET, the UGATE could momentarily rise up to a level greater than the threshold voltage of the MOSFET. This could potentially turn on the upper switch and result in damaging inrush energy. Therefore, if such a situation (when input bus powered up before the bias of the controller and driver is ready) could conceivably be encountered, it is a common practice to place a resistor (RUGPH) across the gate and source of the upper MOSFET to suppress the Miller coupling effect. The value of the resistor depends mainly on the input voltage’s rate of rise, the CGD/CGS ratio, as well as the gate-source threshold of the upper MOSFET. A higher dV/dt, a lower CDS/CGS ratio, and a lower gate-source threshold upper FET will require a smaller resistor to diminish the effect of the internal capacitive coupling. For most applications, a 5k to 10k Ω resistor is typically sufficient, not affecting normal performance and efficiency. The coupling effect can be roughly estimated with the following equations, which assume a fixed linear input ramp and neglect the clamping effect of the body diode of the upper drive and the bootstrap capacitor. Other parasitic components such as lead inductances and PCB capacitances are also not taken into account. These equations are provided for guidance purpose only. Therefore, the actual coupling effect should be examined using a very high impedance (10M Ω or greater) probe to ensure a safe design margin. V GS_MILLER dV dt ------- RC rss 1e V – DS dV dt ------- RC ⋅ iss ⋅ ---------------------------------- – ⎝⎠ ⎜⎟ ⎜⎟ ⎜⎟ ⎜⎟ ⎛⎞ ⋅⋅ = RR UGPH R GI + = C rss C GD = C iss C GD C GS + = (EQ. 5) FIGURE 5. GATE TO SOURCE RESISTOR TO REDUCE UPPER MOSFET MILLER COUPLING VIN QUPPER D S G RGI BOOT DU CDS CGS CGD DL PHASE PVCC CBOOT UGATE ISL6594D |
Similar Part No. - ISL6594DCBZ |
|
Similar Description - ISL6594DCBZ |
|
|
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 |