 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SSL21081AT Datasheet(PDF) 9 Page - NXP Semiconductors |
|
||||||||||||||||||||||||||||||
SSL21081AT Datasheet(HTML) 9 Page - NXP Semiconductors |
|
|
9 / 22 page  SSL21081AT All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved. Product data sheet Rev. 6 — 3 October 2013 9 of 21 NXP Semiconductors SSL21081AT Compact non-dimmable LED driver IC SSL21081AT, there is a maximum limit on the on-time ton(high). The rate of current rise in the coil during the on-phase is proportional to the difference between input voltage and output voltage. Therefore, the peak current cannot be reached before ton(high). As a result the average output current to the LEDs is reduced. 8.3.6 Output Short-circuit Protection (OSP) During the secondary stroke (switch-off time), if a valley is not detected within the off-time limit (toff(high)), then typically the output voltage is less than the minimum limit allowed in the application. This condition can occur either during start-up or due to a short-circuit. A timer tdet(sc) is started when toff(high) is detected. Timer tdet(sc) is reset when a valid valley detection occurs in one of the subsequent cycles or when VCC drops to below VCC(stop). The timer can also be reset if the maximum limit on the on-time of the switch (ton(high)) is reached, which is usually the case at start-up (brownout protection). If no valley is detected and (ton(high)) is not reached before tdet(sc), then it is concluded that a real short-circuit exists. The IC enters latched protection. If VCC drops to below VCC(rst), the IC resets the latched protection mode (see Figure 5). 8.4 VCC supply The SSL21081AT is supplied using three methods: • Under normal operation, the voltage swing on the DVDT pin is rectified within the IC providing current towards the VCC pin • At start-up, there is an internal current source connected to the HV pin. The current source provides internal power until either the dV/dt supply or an external current on the VCC pin provides the supply • Using an auxiliary winding, the voltage can be rectified and connected to the VCC pin via a series resistor. The IC starts up when the voltage at the VCC pin exceeds VCC(startup). The IC locks out (stops switching) when the voltage at the VCC pin is < VCC(stop). The hysteresis between the start and stop levels allows the IC to be supplied by a buffer capacitor until the dV/dt supply is settled. The SSL21081AT has an internal VCC clamp, which is an internal active Zener (or shunt regulator). This internal active Zener limits the voltage on the supply VCC pin to the maximum value of VCC. If the maximum current of the dV/dt supply minus the current consumption of the IC (determined by the load on the gate drivers) is lower than the maximum value of IDD, no external Zener diode is required in the dV/dt supply circuit. Fig 5. OSP logic diagram |
Similar Part No. - SSL21081AT |
|
Similar Description - SSL21081AT |
|
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
