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QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A-A 

ACTIVE RESET ISOLATED 48V INPUT TO 3.3V @30A DC/DC POWER CONVERTER 

 

 

1

 

LT1952 

DESCRIPTION

DESCRIPTION

DESCRIPTION

DESCRIPTION

Demonstration  circuit  1317A-A  is  isolated  input  to 
high  current  output  1/8th  Brick  footprint

1/8th  Brick  footprint

1/8th  Brick  footprint

1/8th  Brick  footprint  converter 

featuring  the  LT

®

1952  switching  controller  with  Ac-

tive  Reset  circuit.  The  Active  Reset  circuit  can  im-
prove  the  efficiency  in  wide  input  voltage  applica-
tions.  Also,  the  Active  Reset  allows  the  implementa-
tion  of  self-driven  synchronous  secondary  rectifiers 
in some applications.  

The DC1317A-A converts isolated 34V to 75V input to 
3.3V output and provides over 30A of output current. 
The converter operates at 300kHz with the peak effi-
ciency  greater  than  93%.  The  DC1317  can  be  easily 
modified  to  generate  output  voltages  in  the  range 
from 0.6V to 48V. The output currents are limited by 
total output power of up to 150W.  

The other available versions of DC1317A are: 

DC1317A-B, 18-72Vin to 5V, 25A 

DC1317A-C, 18-72Vin to 12V, 10A 

DC1317A-D, 18-72Vin to 24V, 5A 

DC1317A-E, 36-72Vin to 5V, 12A  

DC1317A-F, 9-36Vin to 3.3V, 20A 

DC1317A-G, 9-36Vin to 12V, 5A 

DC1317A-H, 9-36Vin to 48V, 1.5A 

 

The DC1317 circuit features soft-start which prevents 
output voltage overshoot on startup or when recover-
ing from overload condition.  

The  DC1317  has  precise  over-current  protection  cir-
cuit that allows for continuous operation under short 
circuit  conditions.  The  low  power  dissipation  under 
short  circuit  conditions  insures  high  reliability  even 
during short circuits. 

The LT1952 can be synchronized to an external clock 
of up to 400kHz. Please refer to LT1952 data sheet for 
design details and applications information. 

Design  files  for  this  circuit  board  are  avai

Design  files  for  this  circuit  board  are  avai

Design  files  for  this  circuit  board  are  avai

Design  files  for  this  circuit  board  are  availlllable. 

able. 

able. 

able. 

Call the LTC factory.

Call the LTC factory.

Call the LTC factory.

Call the LTC factory.    

LT is a trademark of Linear Technology Corporation 

    

Table 1.

Table 1.

Table 1.

Table 1.

 

Performance Summary

Performance Summary

Performance Summary

Performance Summary    

PARAMETER

PARAMETER

PARAMETER

PARAMETER    

CONDITION

CONDITION

CONDITION

CONDITION    

VALUE

VALUE

VALUE

VALUE    

Minimum Input Voltage 

IOUT = 0A to 30A 

34V 

Maximum Input Voltage 

IOUT = 0A to 30A 

75V 

VOUT 

VIN = 34V to 75V, IOUT = 0A to 30A 

3.3V ±3% 

Typical Output Ripple VOUT 

VIN = 34V to 75V, IOUT = 0A to 30A 

50mVP–P 

Nominal Switching Frequency 

 

300kHz 

QUICK START PROCEDUR

QUICK START PROCEDUR

QUICK START PROCEDUR

QUICK START PROCEDURE

E

E

E

    

Demonstration circuit 1317 is easy to set up to evalu-
ate the performance of LT1952 circuit.  Refer  to  Fi

Refer  to  Fi

Refer  to  Fi

Refer  to  Fig-

g-

g-

g-

ure  1  for  proper  measurement  equipment  setup

ure  1  for  proper  measurement  equipment  setup

ure  1  for  proper  measurement  equipment  setup

ure  1  for  proper  measurement  equipment  setup 
and follow the procedure below: 

Summary of Contents for 1317A-A

Page 1: ...t protection cir cuit that allows for continuous operation under short circuit conditions The low power dissipation under short circuit conditions insures high reliability even during short circuits The LT1952 can be synchronized to an external clock of up to 400kHz Please refer to LT1952 data sheet for design details and applications information Design files for this circuit board are avai Design...

Page 2: ... 2 2 Turn on the power at the input NOTE NOTE NOTE NOTE Make sure that the input voltage does not exceed 75V 3 3 3 3 Check for the proper output voltage Vout 3 3V If there is no output temporarily disconnect the load to make sure that the load is not set too high 4 4 4 4 Once the proper output voltage is established ad just the load within the operating range and ob serve the output voltage regula...

Page 3: ...t is suitable for driving the secondary synchronous MOSFET rectifier Q3 Beware that the gate voltage of Q3 depends on the reset circuit Q13 and transformer turns ratio The main benefit of active reset circuit in the case of DC1317A A demo board is high efficiency shown in Figure 3 and small size To achieve such high efficiency all of the power components were care fully selected Please consult LT ...

Page 4: ... tested and debugged by powering the bias circuit separately from the main power circuit To place DC1317 into debug mode remove the resistor R1 and connect 48V 100mA power source to Vb node right side of R1 By doing this the primary PWM controller LT1952 can be activated without the main primary power being applied to Vin To activate the secondary side control circuit LT4430 diode OR a 5V 100mA po...

Page 5: ...l vias for all components that connect to ground planes Do not place any traces on the layers 2 and n 1 to avoid ground planes from being compromised If the PCB layout has to be done on 2 or 4 layer PCB try to stay close to the guidelines outlined above Also maximize the ground connections between compo nents by placing the components tight together Please contact LT factory for additional assista...

Page 6: ...4 Opto 6 GND 2 Comp 5 U4 LT4430 Cin 2x2 2uF Vin D5 PDZ10B Vu1 D2 BAS516 R11 82k 1 6 Vin R1 2 2R R32 332k L1 PA1671 650 Q2 HAT2165 Q3 D6 B0540W R8 2 2R Q12 BC856T D3 Q10 PBSS8110 Vb Vb L2 1 5mH U6 PS2801 1 T1 D11 BAS516 GND Vout Csys 470uF 6 3V C24 47p C9 100p C25 10n R49 2 2R Q13 Si2325 D14 BAS516 R45 10k Vr2 Vr2 R50 2 2R D17 BAS516 R53 200 2 3 4 5 7 8 9 10 11 C33 0 1u C34 0 22uf R54 4 7 Vin Demo ...

Page 7: ...QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A A ACTIVE RESET ISOLATED 48V INPUT TO 3 3V 30A DC DC POWER CONVERTER 7 ...

Page 8: ...QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1317A A ACTIVE RESET ISOLATED 48V INPUT TO 3 3V 30A DC DC POWER CONVERTER 8 ...

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