 |
数据搜索系统，热门电子元器件搜索 |
|
|
数据搜索系统，热门电子元器件搜索 |
|
L6983 数据表(PDF) 21 Page - STMicroelectronics |
|
|
|||||||||||||||||||||||||||||
L6983 数据表(HTML) 21 Page - STMicroelectronics |
|
|
21 / 63 page  6.5 Switch-over feature The switch-over maximizes the efficiency at light load that is crucial for low consumption application. Figure 18. Switch-over PGOOD BOOT SW SW VBIAS VOUT/FB PGND PGND E.P. L6983 VOUT GND CBOOT RPGOOD L RFBH RFBL COUT PGOOD BOOT SW SW VBIAS VOUT/FB PGND PGND E.P. L6983 VOUT GND CBOOT RPGOOD L RFBH RFBL COUT Switch -Over No Switch -Over In order to minimize the regulator quiescent current sink from the input voltage, the VBIAS pin can be connected to an external voltage source in the range of 3 V < VBIAS < VIN. In case the VBIAS pin is connected to the regulated output voltage (VOUT), the total current drawn from the input voltage is given by the following equation: IQVIN=IQOPVIN+ 1ηL6983∙VBIASVIN∙IQOPVBIAS (4) 6.6 Spread spectrum The spread spectrum is selectable by connecting the RFSW resistor to VCC (please refer to Table 7. FSW selection). The internal dithering circuit changes the switching frequency in a range of ± 5%. ∆FSW=5%∙Fsw (5) The device updates the frequency every clock period by fixed steps: • Ramps up in 63 steps from minimum to maximum FSW • Ramps down in 63 steps from maximum to minimum FSW The modulation shape is almost triangular with a frequency of: FDitℎering=Fsw126 (6) 6.7 Overvoltage protection The overvoltage protection monitors the FB pin and enables the low-side MOSFET to discharge the output capacitor if the output voltage is 20% (typ.) over the nominal value. This is a second level protection and it should never be triggered in normal operating conditions if the system is properly dimensioned. In other words, the selection of the external power components and the dynamic performance determined by the compensation network should guarantee an output voltage regulation within the overvoltage threshold even during the worst-case scenario in term of load transitions. The protection is reliable and able to operate even during normal load transitions for a system whose dynamic performance is not in line with the load dynamic request. Consequently, the output voltage regulation would be affected. The L6983 device implements a 1.5 A (IVY_SINK refer to Table 6. Electrical characteristics) negative current limitation to limit the maximum reversed switch current during the overvoltage operation. L6983 Switch-over feature DS13116 - Rev 1 page 21/63 |
|
链接网址 |
| ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 数据表链接 | 链接交换 | 制造商名单 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 |
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
