 |
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 |
|
LTC1702AIGN 数据表(PDF) 32 Page - Linear Technology |
|
|
|||||||||||||||||||||||||||||
LTC1702AIGN 数据表(HTML) 32 Page - Linear Technology |
|
|
32 / 36 page  32 LTC1702A 1702afa APPLICATIONS INFORMATION FAULT BEHAVIOR Changing the Output Voltage on the Fly Some applications use a switching scheme attached to the feedback resistors to allow the system to adjust the LTC1702A output voltage. The voltage can be changed on the fly if desired, but care must be taken to avoid tripping the overvoltage fault circuit. Stepping the voltage upwards abruptly is safe, but stepping down quickly by more than 15% can leave the system in a state where the output voltage is still at the old higher level, but the feedback node is set to expect a new, substantially lower voltage. If this condition persists for more than 10 µs, the overvoltage fault circuitry will fire and latch off the LTC1702A. The simplest solution is to disable the fault circuit by grounding the FAULT pin. Systems that must keep the fault circuit active should ensure that the output voltage is TYPICAL APPLICATIONS 3.3VIN, 2.5V/1.8V Output Power Supply LTC1702A PVCC BOOST1 BG1 TG1 SW1 IMAX1 PGOOD1 FCB RUN/SS COMP1 SGND FB1 IMAX2 BOOST2 BG2 TG2 SW2 PGND PGOOD2 FAULT RUN/SS2 COMP2 FB2 VCC C5 1 µF R1 10 Ω C6 1 µF C8 1 µF R2 28.7k R8 25.5k R10 2.4k R9 27k 1702A TA02 R3 4.3k R4 10k 1% C11 820pF C9 20pF C10 100pF R7 68k C15 1 µF VOUT2 1.8V 12A C7 1 µF R5 8.06k 1% 10k Q2A Q2B Q1B Q1A D3 D2 D1, D2: MOTOROLA MBR0520LT1 D3: MOTOROLA MBRS320T3 C1: KEMET T510X477M006AS C12, C20: PANASONIC EEFUE0G181R L1: SUMIDA CEP1254712-T007 L2: SUMIDA CDRH744734-JPS023 Q1A, Q1B, Q2A, Q2B: SILICONIX Si9804 Q3, Q4: 1/2 SILICONIX Si4966 D1 GND L1 0.68 µH C12 180 µF ×3 C4 10 µF C3 1 µF C2 1 µF C16 1 µF C1 470 µF ×2 + Q3 Q4 C19 1000pF C17 100pF C18 1000pF R12 10.7k 1% R13 4.99k 1% L2 1 µH C20 180 µF C21 1 µF VOUT1 2.5V 5A GND VIN VIN FAULT PGOOD2 VIN 3.3V ±5% + + PGOOD1 10k never programmed to step down by more than 15% in any single step. The safest strategy is to step the output down by 10% or less at a time and wait for the output to settle to the new value before taking subsequent steps. VID Applications Certain microprocessors specify a set of codes that corre- spond to power supply voltages required from the regula- tor system. If these codes are changed on the fly, the same caveats as above apply. In addition, the switching matrix that programs the output voltage may vary its resistance significantly over the entire span of output voltages, potentially changing the loop compensation if the circuit is not designed properly. With a typical type 3 feedback loop (Figure 3), make sure that the RB resistor is modified to set the output voltage. The R1 resistor must stay constant to ensure that the loop compensation is not affected. |
|
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
