Vicor PI33XX-XX User Manual

Cool-Power
®
PI33XX-XX
Multi-Phase Design Guide
1
out
in
in
in
R1
out
out
PGD
out
in
in
R1
out
PGD
1
2
3
2
(a) (b)
Description
The Multi-Phase Design Guide provides an overview to paralleling two or three PI33XX-XX devices together without any change required to the basic single-phase power stage or compensation design. Paralleling multiple PI33XX modules increases the output current capability and reduces the output voltage ripple. For information on paralleling more than three regulators, please contact Picor.
Basic Connections
The PI33XX family of Cool-Power products employs a ZVS topology which operates exclusively in discontinuous and critical conduction mode. Therefore, to derive real-time output current
information, each device’s error amplifier output
(EAO) is trimmed to a nominal level (2.2V) when supporting the maximum rated output load. This will allow the EAO to track the output load. By trimming the EAO this way, additional regulators can be connected in parallel to deliver equal amount of current to a single regulated point by linking each
regulator’s EAO pin together. The basic pin
connections needed to parallel two or three regulators are shown in Figure 1. The SYNCO pins are for phase synchronization, TRK is for soft-start and fault shutdown tracking. EAO is for current sharing between phases.
Figure 1 – Basic Connections for Parallel Operation
This method will allow the regulators to remain in synchronization when the system’s operational frequency stretches at high output loads. Figure 2 shows the basic synchronization connections and the phase requiring delays in red.
Two and Three Phases
The PI33XX-2X can be synchronized in a closed loop configuration to up to three phases by adding an additional 2.5kΩ (R1) feedback resistor to the design and incorporating the PGD pin.
vicorpower.com Rev 1.0 Cool-Power® 800 735.6200 11/2012 Page 1 of 4
Figure 2 - SYNCI (In) and SYNCO (Out) Connection for
Two and Three Phase Design
Multi-Phase Design Guide
Sync Delay and Code
Regulator
1 2 3
2-phase
- -
3-phase
-
0Eh 1/3
0Eh 1/3
A[5]
A[4]
A[3]
A[2]
A[1]
A[0]
R/W
ADR1
ADR2
HEX
DEC
1 0 0 1 0 0 0 X 0 0 48
72
1 0 0 1 0 0 1 X 0
NC
49
73
1 0 0 1 0 1 0 X 0 1 4A
74
1 0 0 1 0 1 1 X NC 0 4B
75
1 0 0 1 0 0 0 X NC
NC
4C
76 1 0 0 1 1 0 1 X
NC 1 4D
77
1 0 0 1 1 1 0 X 1 0 4E
78 1 0 0 1 1 1 1 X 1 1+NC
4F
79
The required per phase delay and programming code are presented in the following table.
Table 1 - Phase Programming Codes
Synchronization / Phase Delay
Two regulators connected in parallel operation do not require any delay programming. As a default setting, the PI33XX-XX will trigger on the falling edge and will operate 180 out of phase with the master. For a three phase operation, a 1/3 phase delay is required for two of the regulators to ensure proper phase spacing. Synchronization and phase delay is only programmable with I 2X).
2CTM
option regulators (PI33XX-
I2C Device Address
The PI33XX-2X supports floating addressing so that two address lines allows for up to 8 programmable addresses.
The address is 7 bit with the read/write bit not included. Table 2 shows the address range that can be achieved using all possible combinations of ADR0 (pad G1) and ADR1 (pad H1). Bits A[6]-A[3] are fixed internally and may not be changed. The least significant 3 bits; A[2]-A[0], will assume the values in the table based on the decoding of ADR1 and ADR0. A zero or one indicates the logic strength of the bit and
“NC” indicates that the pin is floating or not
connected. The HEX column indicates the final address in hexadecimal, while the DEC column is the decimal address value.
vicorpower.com Rev 1.0 Cool-Power® 800 735.6200 11/2012 Page 2 of 4
Table 2 - PI33XX-2X Device Addressing
Loading...
+ 2 hidden pages