300V Datasheet, PDF (11/14 Pages) Powerbox – 5 0 - 5 0 0 WAT T S - D C / D C C O N V E R T E R S

300V Input
Secondary Control - SC PIN
Output Voltage Programming
The output voltage of the converter can be adjusted or
programmed via fixed resistors, potentiometers or voltage
DACs. See Figure 8.
Error Amplifier
–
+
1kΩ
1.23V
100Ω typ.
+OUT
+S
SC
0.033µF
-S
–OUT
Ru
Trim Up
Rd
Trim Down
Load
R_d (Ω) =
1,000 ^VOUT
V_NOM – V_OUT
R_U (Ω) =
1,000 (VOUT –1.23) ^VNOM
1.23 (V_OUT – V_NOM)
– 1,000
Figure 8 — Output voltage trim down and trim up circuit
Trim Down
1. This converter is not a constant power device – it has a
constant current limit. Hence, available output power is
reduced by the same percentage that output voltage is
trimmed down. Do not exceed maximum rated output current.
2. The trim down resistor must be connected between the SC
and -S pins. Do not bypass the SC pin directly with a capacitor.
Trim Up
1. The converter is rated for a maximum delivered power. To
ensure that maximum rated power is not exceeded, reduce
maximum output current by the same percentage increase in
output voltage.
2. The trim up resistor must be connected between the SC and
+S pins. Do not bypass the SC pin directly with a capacitor.
3. Do not trim the converter above maximum trim range (typically
+10%) or the output over voltage protection circuitry may
be activated.
Trim resistor values calculated automatically:
On-line calculators for trim resistor values are available on
the vicor website at:
asp.vicorpower.com/calculators/calculators.asp?calc=1
Resistor values can be calculated for fixed trim up, fixed
trim down and for variable trim up or down.
Parallel Bus - PR PIN
Parallel Operation
The PR pin supports paralleling for increased power with N+1
(N+M) redundancy. Modules of the same input voltage, output
voltage, and power level will current share if all PR pins are
suitably interfaced.
300V Mini Family
Page 11 of 14
Rev 9.5
03/2017
Compatible interface architectures include the following:
AC coupled single-wire interface. All PR pins are connected
to a single communication bus through 0.001µF (500V)
capacitors. This interface supports current sharing and is fault
tolerant except for the communication bus. Up to three
converters may be paralleled by this method. See Figure 9.
Transformer coupled interface. For paralleling four or more
converters a transformer coupled interface is required, and under
certain conditions a PR buffer circuit.
For details on parallel operation please refer to the
Design Guide & Applications Manual for Maxi, Mini, Micro Family.
4.7nF
+
+IN
0.2µF
0.001µF _R1*
PC
Module 1
PR
–
–IN
Low inductance
ground plane
or bus
4.7nF
4.7nF
+IN
0.2µF
0.001µF _R1*
PC
Module 2
PR
–IN
Parallel
Bus
4.7nF
Figure 9 — AC coupled single-wire interface
* See Maxi, Mini, Micro Design Guide
4.7nF
+
+IN
0.2µF
T1 _R1*
PC
Module 1
PR
–IN
–
4.7nF
4.7nF
0.2µF
T2 _R1*
Parallel
Bus
4.7nF
+IN
PC
Module 2
PR
–IN
Figure 10 — Transformer-coupled interface
Number of Converters in Parallel
2
3
4
5 or more
*R1 value Ω
75
50
33
refer to application note:
Designing High-Power Arrays
using Maxi, Mini, Micro
Family DC-DC Converters
vicorpower.com
800 927.9474