Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

LTC3901 Datasheet(PDF) 8 Page - Linear Technology

Part # LTC3901
Description  Secondary Side Synchronous Driver for Push-Pull and Full-Bridge Converters
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  LINER [Linear Technology]
Direct Link  http://www.linear.com
Logo LINER - Linear Technology

LTC3901 Datasheet(HTML) 8 Page - Linear Technology

Back Button LTC3901_15 Datasheet HTML 4Page - Linear Technology LTC3901_15 Datasheet HTML 5Page - Linear Technology LTC3901_15 Datasheet HTML 6Page - Linear Technology LTC3901_15 Datasheet HTML 7Page - Linear Technology LTC3901_15 Datasheet HTML 8Page - Linear Technology LTC3901_15 Datasheet HTML 9Page - Linear Technology LTC3901_15 Datasheet HTML 10Page - Linear Technology LTC3901_15 Datasheet HTML 11Page - Linear Technology LTC3901_15 Datasheet HTML 12Page - Linear Technology Next Button
Zoom Inzoom in Zoom Outzoom out
 8 / 16 page
background image
LTC3901
8
3901f
polarity. In some situations, for example during power-up
or power-down, the SYNC pulse magnitude may be low
(slightly higher or lower than the threshold of the compara-
tors). This can cause only one of the SYNC comparators to
trip. This also appears as a double pulse to the sequential
logic and both drivers will be shut off.
Current Sense
The differential input current sense comparators, ISE and
ISF (Figure 6), are used for sensing the voltage across the
drain-to-source terminal of the MOSFET through the CSX+
and CSXpins. There are two sets of comparator inputs,
one for each MOSFET (ME and MF). If the inductor current
reverses into the MOSFET causing CSX+ to rise above
CSXby more than 10.5mV, the LTC3901 turns off the
respective MOSFET. This comparator is used to prevent
inductor reverse current buildup during power-down or
Burst Mode operation, which may cause damage to the
MOSFETs. The 10.5mV input threshold has a positive
temperature coefficient, which closely matches the TC of
the external MOSFET RDS(ON). The current sense com-
parator is only active 250ns after the respective driver
APPLICATIO S I FOR ATIO
The timeout period is determined predominantly by the
external RTMR and CTMR values and is independent of the
VCC voltage. This independence is achieved by making the
timeout threshold a ratio of VCC. The ratio is 0.2x, set
internally by R1 and R2 (see Figure 3). The Timeout period
should be programmed to around 1 period of the primary
switching frequency using the following formula:
TIMEOUT = 0.2 • RTMR • CTMR + 0.27E-06
To reduce error in the timeout setting due to the discharge
time, select CTMR between 100pF and 1000pF. Start with
a CTMR around 470pF and then calculate the required
RTMR. CTMR should be placed as close as possible to the
LTC3901 with minimum PCB trace between CTMR, the
TIMER pin and GND. This is to reduce any ringing caused
by the PCB trace inductance when CTMR discharges. This
ringing may introduce error to the timeout setting.
The timer input also includes a current sinking clamp
circuit (ZTMR in Figure 3) that clamps this pin to about
0.5 • VCC if there is missing SYNC/timer reset pulse. This
clamp circuit prevents the timer capacitor from getting
fully charged up to the rail, which would result in a longer
discharge time. The current sinking capability of the circuit
is around 1mA.
The timeout function can be disabled by connecting the
timer pin to GND.
Synchronization Sequence
A typical push-pull converter cycle always turns off ME
and MF alternately. The SYNC input should alternate
between a positive and negative pulse. The LTC3901
includes a sequential logic to monitor the SYNC input
pulses. If after one positive pulse the SYNC comparator
receives another positive pulse, the LTC3901 sequential
logic shuts off both drivers until a negative pulse appears.
The same applies to double negative pulses; the driver will
turn on only after receiving a positive pulse. This is to
protect the external components in situations where only
one polarity of the SYNC pulse is present and the corre-
sponding driver remains on. Figure 5 shows the SYNC
double pulse operation.
The LTC3901 has two separate SYNC comparators (S+ and
Sin the Block Diagram) to detect the positive and nega-
tive pulses. The threshold voltages of both comparators
are designed to be of the same magnitude but opposite in
SYNC
ME
MF
3901 F05
0V
EXPECTED POSITIVE SYNC PULSE,
MF PULLS HIGH
SECOND NEGATIVE SYNC PULSE,
BOTH ME AND MF PULL LOW
Figure 5. SYNC Double Pulse Operation
+
6
5
RCSE1
T1
RCSE2
CSE+
ISE
ISF
CSE
ZCSE
11V
10.5mV
LTC3901
ME
RCSE3
11
12
RCSF1
RCSF2
CSF+
CSF
MF
3901 F06
RCSF3
+
ZCSF
11V
10.5mV
Figure 6. Current Sense Circuit


Similar Part No. - LTC3901_15

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LTC3901EGN LINER-LTC3901EGN Datasheet
229Kb / 16P
   Secondary Side Synchronous Driver for Push-Pull and Full-Bridge Converters
More results

Similar Description - LTC3901_15

ManufacturerPart #DatasheetDescription
logo
Linear Technology
LTC3901 LINER-LTC3901 Datasheet
229Kb / 16P
   Secondary Side Synchronous Driver for Push-Pull and Full-Bridge Converters
logo
Maxim Integrated Produc...
MAX17606 MAXIM-MAX17606 Datasheet
507Kb / 12P
   Secondary-Side Synchronous MOSFET Driver for Flyback Converters
Rev 0; 10/15
logo
ON Semiconductor
FAN6250M6X ONSEMI-FAN6250M6X Datasheet
156Kb / 9P
   Secondary Side Synchronous Rectifier Controller for Flyback Converters
October, 2018 ??Rev. 0
FAN6292CMX ONSEMI-FAN6292CMX Datasheet
235Kb / 14P
   Secondary Side Synchronous Rectifier Controller for Flyback Converters
February, 2019 ??Rev. 1
FAN6241M6X ONSEMI-FAN6241M6X Datasheet
561Kb / 11P
   Secondary Side Synchronous Rectifier Controller for Flyback Converters
March, 2020 ??Rev. 1
NCP4305 ONSEMI-NCP4305 Datasheet
702Kb / 52P
   Secondary Side Synchronous Rectification Driver
June, 2015 ??Rev. 1
logo
Linear Technology
LT8309 LINER-LT8309_15 Datasheet
232Kb / 14P
   Secondary-Side Synchronous Rectifier Driver
logo
ON Semiconductor
NCP4306 ONSEMI-NCP4306 Datasheet
1Mb / 49P
   Secondary Side Synchronous Rectification Driver
December, 2017 ??Rev. 1
FAN6240 ONSEMI-FAN6240 Datasheet
521Kb / 10P
   Secondary-Side Synchronous Rectifier Controller Flyback Converters
July 2016 Rev. 1.0
logo
STMicroelectronics
L293C STMICROELECTRONICS-L293C Datasheet
74Kb / 5P
   PUSH-BRIDGE DRIVER PUSH-PULL FOUR CHANNEL/DUAL
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


Datasheet Download

Go To PDF Page


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


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
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