 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
FSQ0765R Datasheet(PDF) 13 Page - Fairchild Semiconductor |
|
||||||||||||||||||||||||||||||
FSQ0765R Datasheet(HTML) 13 Page - Fairchild Semiconductor |
|
|
13 / 22 page  © 2008 Fairchild Semiconductor Corporation www.fairchildsemi.com FSQ0565R, FSQ0765R Rev. 1.0.1 13 The switching frequency is the combination of blank time (tB) and detection time window (tW). In case of a heavy load, the sync voltage remains flat after tB and waits for valley detection during tW. This leads to a low switching frequency not suitable for heavy loads. To correct this drawback, additional timing is used. The timing conditions are described in Figures 25, 26, and 27. When the Vsync remains flat higher than 4.4V at the end of tB that is tX, the next switching cycle starts after internal delay time from tX. In the second case, the next switching occurs on the valley when the Vsync goes below 4.4V within tB. Once Vsync detects the first valley within tB, the other switching cycle follows classical QRC operation. Figure 25. Vsync > 4.4V at tX Figure 26. Vsync < 4.4V at tX Figure 27. After Vsync Finds First Valley 4. Protection Circuits: The FSQ-series has several self-protective functions, such as Overload Protection (OLP), Abnormal Over-Current Protection (AOCP), Over-Voltage Protection (OVP), and Thermal Shutdown (TSD). All the protections are implemented as auto- restart mode. Once the fault condition is detected, switching is terminated and the SenseFET remains off. This causes VCC to fall. When VCC falls down to the Under-Voltage Lockout (UVLO) stop voltage of 8V, the protection is reset and the start-up circuit charges the VCC capacitor. When the VCC reaches the start voltage of 12V, normal operation resumes. If the fault condition is not removed, the SenseFET remains off and VCC drops to stop voltage again. In this manner, the auto-restart can alternately enable and disable the switching of the power SenseFET until the fault condition is eliminated. Because these protection circuits are fully integrated into the IC without external components, the reliability is improved without increasing cost. Figure 28. Auto Restart Protection Waveforms t B=15μs I DS V DS V sync internal delay I DS 4.4V 1.2V 1.0V t X FSQ0765R Rev. 00 t B=15μs I DS V DS V sync internal delay I DS 4.4V 1.2V 1.0V t X FSQ0765R Rev. 00 t B=15μs I DS I DS V DS V sync internal delay 4.4V 1.2V 1.0V ingnore t X FSQ0765R Rev. 00 Fault situation 8V 12V V CC V DS t Fault occurs Fault removed Normal operation Normal operation Power on FSQ0765R Rev. 00 |
Similar Part No. - FSQ0765R |
|
Similar Description - FSQ0765R |
|
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
