 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LTC3413EFE Datasheet(PDF) 6 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LTC3413EFE Datasheet(HTML) 6 Page - Linear Technology |
|
|
6 / 16 page  6 LTC3413 sn3413 3413fs OPERATIO Main Control Loop The LTC3413 is a monolithic, constant frequency, current mode step-down DC/DC converter that is capable of sourc- ing and sinking current at the output. During normal op- eration, the internal top power switch (P-channel MOSFET) is turned on at the beginning of each clock cycle. Current in the inductor increases until the current comparator trips and turns off the top power MOSFET. The peak inductor current at which the current comparator shuts off the top power switch is controlled by the voltage on the ITH pin. The error amplifier adjusts the voltage on the ITH pin by comparing the feedback signal on the VFB pin with a refer- ence voltage that is equal to one-half of the voltage on the VREF pin. When the load current increases, it causes a reduction in the feedback voltage relative to the reference. The error amplifier raises the ITH voltage until the average inductor current matches the new load current. When the top power MOSFET shuts off, the synchronous power switch (N-channel MOSFET) turns on until either the bot- tom current limit is reached or the beginning of the next clock cycle. The bottom current limit is set at – 7A. The operating frequency is set by an external resistor connected between the RT pin and ground. The switching frequency can range from 300kHz to 2MHz. Overvoltage and undervoltage comparators will pull the PGOOD output low if the output voltage comes out of regulation by ±10%. In an overvoltage condition, the top power MOSFET is turned off and the bottom power MOSFET is switched on until either the overvoltage condition clears or the bottom MOSFET’s current limit is reached. Dropout Operation When the input supply voltage decreases toward the output voltage, the duty cycle increases toward the maxi- mum on-time. Further reduction of the supply voltage forces the main switch to remain on for more than one cycle until it reaches 100% duty cycle. The output voltage will then be determined by the input voltage minus the voltage drop across the internal P-channel MOSFET and the inductor. Low Supply Operation The LTC3413 is designed to operate down to an SVIN input supply voltage of 2.25V. One important consideration at low input supply voltages is that the RDS(ON) of the P- channel and N-channel power switches increases. The user should calculate the power dissipation when the LTC3413 is used at 100% duty cycle with low input voltages to ensure that thermal limits are not exceeded. Slope Compensation and Inductor Peak Current Slope compensation provides stability in constant fre- quency architectures by preventing subharmonic oscilla- tions at duty cycles greater than 50%. It is accomplished internally by adding a compensating ramp to the inductor current signal at duty cycles in excess of 40%. Normally, the maximum inductor peak current is reduced when slope compensation is added. In the LTC3413, however, slope compensation recovery is implemented to keep the maxi- mum inductor peak current constant throughout the range of duty cycles. Short-Circuit Protection When the output is shorted to ground, the inductor current decays very slowly during a single switching cycle. To prevent current runaway from occurring, a secondary current limit is imposed on the inductor current. If the inductor valley current increases greater than 5A, the top power MOSFET will be held off and switching cycles will be skipped until the inductor current is reduced. |
Similar Part No. - LTC3413EFE |
|
Similar Description - LTC3413EFE |
|
|
|
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
