Electronic Components Datasheet Search |
|
TD230 Datasheet(PDF) 7 Page - STMicroelectronics |
|
TD230 Datasheet(HTML) 7 Page - STMicroelectronics |
7 / 15 page where CISS is the input capacitance of the power MOSFET1/2 and VTH, the threshold voltage of the MOSFET (typically 5V). This reconduction time can be extended with an external soft start capacitor CSS1/2 as shown in figure 1 CISS will therefore simply be replaced by CISS +CSS 1/2. 1 2 3 4 5 6 7 9 10 11 12 13 14 8 15 16 P Vcc LBOOS T CB OOS T PM1 GND PM2 OS C GND NVcc REF1 GC1 S E NSP INHIBIT S HUTDOWN S ENSN GC 2 REF2 Vcc+ GND Vcc- LBOO S T CTRIP 1 CTRIP 2 RS 2 NMos to BOARD CS S 1 C ONTRO L NMOS from BO ARD CS S 2 RS 1 CBO OS T Figure 1 : Dual Electronic Circuit Breaker Application If the fault (over current condition) still remains after the reconduction state of the MOSFET1/2 has been reached, the current through NMOS1/2 will overpass the limitation given by equation (i), and the NMOS 1/2 will immediately be switched off again. Figure 2 shows the current limitation which is operated on every restart attempt. Figure 2 : TD230 as Current Limitor Trace A represents the Gate-Source Voltage of the Power Mosfet (0 to 13,4V). Trace B represents the voltage across the Sense Resistor (68m Ω) in direct relation with the current through it (0 to ~1A). Note that the first current peak which is due to an over current is limited only by the reaction time of the TD230. This off time is tied to the value of the external soft start capacitor CSS 1/2 by equation (iii) : • tOFF =RDSON xCSS (iii) While in current limitation mode, the NMOS1/2 dis- sipates low power due to the fact that the ON/OFF cycle time rate is very low. Note that the higher the value of CSS1/2 are, the more the NMOS1/2 will stay in linear mode during current limitation. Note that at Power ON, or in the case of live insertion, the inrush current is automatically limited thanks to the slow gate charge of the MOSFET which switches ON softly due to the time constant given in equation (ii). 2.2. Fault Time Limitation The repetitive switching off of the MOSFET will come to an end under two conditions : • either the fault has disappeared,and the cur- rent through the shunt resistors RS 1/2 has come back to its nominal value : the system keeps running normally. External line defaults (lightning, line breakage, etc...) are usual causes for such temporary over currents. • either the repetitive switching off has lasted over an externally adjustable time and the TD230 has definitively switched off the corre- sponding NMOS : the system waits to be re- set. Equipment faults (component short circuit, over heat, etc ...) are usual causes for lasting over currents. This fault time supervision is done by the compari- son of the output voltage to 75% of the nominal supply voltage. As soon as the output voltage is detected under 0.75xVcc(+/-), the corresponding external capacitors CTRIP1/2 is charged by a fixed current source IP/N2 -IP/N3 (3 µA). When the voltage across CTRIP1/2 reaches 1.20V, the corresponding NMOS is definitively switched off and the SHUT- DOWN pin is active low. TD230 7/15 |
Similar Part No. - TD230 |
|
Similar Description - TD230 |
|
|
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 |