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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 

 

 

2

 

NOTE:

NOTE:

NOTE:

NOTE:

 

When  measuring  the  input  or  output  voltage 

ripple, care must be taken to avoid a long ground lead 
on the oscilloscope probe. Measure the input or out-
put  voltage  ripple  by  touching  the  probe  tip  directly 
across the Vin or Vout and GND terminals. See Figure 
2. for proper scope probe technique. 

1.

1.

1.

1.

 

With power off, connect the input power supply to 
Vin and GND. Make sure that the input power sup-
ply  has  sufficient  current  rating  at  minimum  input 
voltage for the required output load. 

2.

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 regulation, ripple voltage, 
efficiency and other parameters. 

5.

5.

5.

5.

 

The  DC1317  is  equipped  with  an  output  capacitor 
CSYS  (470uF)  that  approximates  typical  system 
rail  capacitance.  If  system  board  already  has  ca-
pacitance of similar value CSYS can be removed.  

 

 

    

    

    

Figure 1. Pr

Figure 1. Pr

Figure 1. Pr

Figure 1. Proper Measurement Equipment Setup

oper Measurement Equipment Setup

oper Measurement Equipment Setup

oper Measurement Equipment Setup    

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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