 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC1622IS8 Datasheet(PDF) 5 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC1622IS8 Datasheet(HTML) 5 Page - Linear Technology |
|
|
5 / 16 page  5 LTC1622 FUNCTIONAL DIAGRA OPERATIO Main Control Loop The LTC1622 is a constant frequency current mode switch- ing regulator. During normal operation, the external P-channel power MOSFET is turned on each cycle when the oscillator sets the RS latch (RS1) and turned off when the current comparator (ICOMP) resets the latch. The peak inductor current at which ICOMP resets the RS latch is controlled by the voltage on the ITH pin, which is the output of the error amplifier EA. An external resistive divider connected between VOUT and ground allows EA to receive an output feedback voltage VFB. 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. The main control loop is shut down by pulling the RUN/SS pin low. Releasing RUN/SS allows an internal 2.5 µA (Refer to Functional Diagram) current source to charge up the soft-start capacitor CSS. When CSS reaches 0.7V, the main control loop is enabled with the ITH voltage clamped at approximately 5% of its maximum value. As CSS continues to charge, ITH is gradu- ally released allowing normal operation to resume. Comparator OV guards against transient overshoots > 7.5% by turning off the P-channel power MOSFET and keeping it off until the fault is removed. Burst Mode Operation The LTC1622 can be enabled to go into Burst Mode operation at low load currents simply by leaving the SYNC/ MODE pin open or connecting it to a voltage of at least 2V. In this mode, the peak current of the inductor is set as if VITH = 0.36V (at low duty cycles) even though the voltage at the ITH pin is at lower value. If the inductor’s average current is greater than the load requirement, the voltage at + – + – + – + – + – + – BURST DEFEAT 1 µA 5 SYNC/ MODE 3 6 4 2 S RQ BURST RS1 0.12V SLEEP SENSE– EN 1 0.36V 8 PDRV OV 1622 BD 7 GND VREF 0.8V RUN/SS VIN SLOPE COMP Y = “0” ONLY WHEN X IS A CONSTANT “1” OTHERWISE Y = “1” FREQ SHIFT OSC 2.5 µA gm = 0.5m EA SWITCHING LOGIC AND BLANKING CIRCUIT RUN/ SOFT-START VREF + 60mV SHUTDOWN VFB 0.3V VIN VIN VIN VCC ICOMP ITH X Y VIN 0.8V REFERENCE UVLO TRIP = 1.97V 0.8V VREF |
Similar Part No. - LTC1622IS8 |
|
Similar Description - LTC1622IS8 |
|
|
|
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
