 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC1735IGN Datasheet(PDF) 9 Page - Linear Technology |
|
|
|||||||||||||||||||||||||||||
LTC1735IGN Datasheet(HTML) 9 Page - Linear Technology |
|
|
9 / 32 page  9 LTC1735 1735fc FU CTIO AL DIAGRA SW – + + – 0.86V – + 0.55V 2.4V 0.8V 0.86V I1 + – I2 + – EA A BURST DISABLE FC OV gm =1.3m B – + 4.7V IREV + – + – F FC S R Q DROP OUT DET 0.8V REF SWITCH LOGIC SD 6V R1 RUN/SS CSS RC VOSENSE VFB 1.2 µA RUN SOFT- START + OVER- CURRENT LATCHOFF SD ITH CC 0.17 µA OSC 4(VFB) BUFFERED ITH SLOPE COMP + – – + 3mV ICMP R2 2k 45k BOT TOP ON FORCE BOT 45k 30k 30k SENSE+ SENSE– SYNC 1.2V 0.8V C TOP UVL BOT INTVCC 5.2V LDO REG VIN + CINTVCC VOUT VSEC INTVCC BG PGND VIN VIN BOOST TG INTVCC CB DB D1 COSC + CIN + CSEC + COUT EXTVCC FCB SGND COSC RSENSE 1735 FD PGOOD LTC1735F ONLY + – 0.74V OPERATIO (Refer to Functional Diagram) Main Control Loop The LTC1735 uses a constant frequency, current mode step-down architecture. During normal operation, the top MOSFET is turned on each cycle when the oscillator sets the RS latch and turned off when the main current comparator I1 resets the RS latch. The peak inductor current at which I1 resets the RS latch is controlled by the voltage on Pin 3 (ITH), which is the output of error amplifier EA. Pin 6 (VOSENSE), described in the pin func- tions, allows EA to receive an output feedback voltage VFB from an external resistive divider. When the load current increases, it causes a slight decrease in VFB relative to the 0.8V reference, which in turn causes the ITH voltage to increase until the average inductor current matches the new load current. While the top MOSFET is off, the bottom MOSFET is turned on until either the inductor current starts to reverse, as indicated by current comparator I2, or the beginning of the next cycle. The top MOSFET driver is powered from a floating boot- strap capacitor CB. This capacitor is normally recharged from INTVCC through an external diode when the top MOSFET is turned off. As VIN decreases towards VOUT, the converter will attempt to turn on the top MOSFET continu- ously (“dropout’’). A dropout counter detects this condi- tion and forces the top MOSFET to turn off for about 500ns every tenth cycle to recharge the bootstrap capacitor. |
|
Link URL |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link to Datasheet | 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
