24V Input
Compatible interface architectures include the following:
Secondary Control – SC Pin
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.
Output Voltage Programming
The output voltage of the converter can be adjusted or
programmed via fixed resistors, potentiometers or voltage
DACs. See Figure 8.
Transformer-coupled interface. For paralleling four or more
converters a transformer coupled interface is required, and under
certain conditions a PR buffer circuit.
+OUT
+S
For details on parallel operation please refer to the
Design Guide & Applications Manual for Maxi, Mini, Micro Family.
Error Amplifier
Ru
Trim Up
–
SC
+
Load
1kΩ
Rd
0.033µF
-S
Trim Down
1.23V
4.7nF
+
–
+IN
PC
PR
–IN
0.2µF
100Ω typ.
–OUT
0.001µF
Module 1
Module 2
R1*
V
1,000
OUT
Rd (Ω)
=
=
4.7nF
4.7nF
Low inductance
ground plane
or bus
VNOM – VOUT
VOUT
VNOM
)
1,000 (
–1.23)
RU (Ω)
– 1,000
1.23 (VOUT – VNOM
+IN
PC
PR
–IN
0.2µF
Figure 8 — Output voltage trim-down and trim-up circuit
0.001µF
R1*
Trim Down
4.7nF
Parallel
Bus
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.
Figure 9 — AC-coupled single-wire interface
* See Maxi, Mini, Micro Design Guide
2. The trim-down resistor must be connected between the SC
and –S pins. Do not bypass the SC pin directly with a capacitor.
4.7nF
+IN
+
–
Trim Up
0.2µF
R1*
PC
Module 1
T1
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.
PR
–IN
4.7nF
4.7nF
2. The trim-up resistor must be connected between the SC and
+IN
PC
PR
–IN
+S pins. Do not bypass the SC pin directly with a capacitor.
0.2µF
R1*
Module 2
T2
3. Do not trim the converter above maximum trim range (typically
+10%) or the output over voltage protection circuitry may
be activated.
4.7nF
Parallel
Bus
Trim resistor values calculated automatically:
Figure 10 — Transformer-coupled interface
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.
Number of Converters in Parallel *R1 value Ω
2
75
50
33
3
Parallel Bus – PR Pin
4
5 or more
refer to application note:
Designing High-Power Arrays
using Maxi, Mini, Micro
Family DC-DC Converters
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.
24V Mini Family
Page 12 of 15
Rev 5.6
02/2021
QQ：1902134819 复制
