CPFE500F Application Note Document Number : 61066 iss 2 Page 1 of 17
CPFE500
AC/DC Power Supply Series
APPLICATION NOTE
CPFE500F Application Note Document Number : 61066 iss 2 Page 2 of 17
INDEX
1. INPUT..................................................................................................................................................................3
AC INPUT LINE REQUIREMENTS ..................................................................................................................... 3
2. DC OUTPUT .......................................................................................................................................................3
OUTPUT VOLTAGES .........................................................................................................................................3
REMOTE SENSE ................................................................................................................................................ 3
OUTPUT OR-ING DIODE ...................................................................................................................................3
OUTPUT VOLTAGE TRIM .................................................................................................................................. 4
OUTPUT GOOD LED .......................................................................................................................................... 5
EFFICIENCY .......................................................................................................................................................5
CAPACITIVE LOAD OPERATION ......................................................................................................................5
SERIES CONNECTION ......................................................................................................................................5
PARALLEL CONNECTION .................................................................................................................................5
3. OUTPUT CHARACTERISTICS ..........................................................................................................................7
RIPPLE / NOISE.................................................................................................................................................. 7
POWER SUPPLY TIMING ..................................................................................................................................8
4. CONTROL SIGNALS .......................................................................................................................................... 8
AUXILIARY SUPPLY (AUX) ................................................................................................................................ 9
POWER ON SIGNAL (ENA)................................................................................................................................ 9
INVERTER OUTPUT GOOD (IOG)..................................................................................................................... 9
REMOTE ON/OFF............................................................................................................................................... 9
5. OUTPUT PROTECTION ................................................................................................................................... 11
NO LOAD OPERATION ....................................................................................................................................11
OVER CURRENT OPERATION (OCP) ............................................................................................................11
OVER TEMPERATURE PROTECTION (OTP)................................................................................................. 11
OVER VOLTAGE PROTECTION (OVP)........................................................................................................... 11
6. COOLING REQUIREMENTS............................................................................................................................ 12
7. PSU MOUNTING........................................................................................................................................... 13
8. RELIABILITY .....................................................................................................................................................14
9. ELECTROMAGNETIC COMPATIBILITY.......................................................................................................... 15
INSTALLATION GUIDELINES FOR EMC ........................................................................................................ 16
10. CONNECTION ................................................................................................................................................ 17
AC INPUT CONNECTOR (J1) MATING PARTS ..............................................................................................17
AC INPUT CONNECTOR (J1) PIN DEFINITION..............................................................................................17
SIGNAL CONNECTORS (J2,J3) MATING PARTS........................................................................................... 17
SIGNAL CONNECTORS (J2,J3) PIN DEFINITION ..........................................................................................17
POWER TERMINALS .......................................................................................................................................17
11. WEIGHTS........................................................................................................................................................17
12. TEST RESULTS .............................................................................................................................................17
CPFE500F Application Note Document Number : 61066 iss 2 Page 3 of 17
1. INPUT
AC INPUT LINE REQUIREMENTS
See datasheet for specification of input line requirements (including Input voltage range, Input frequency, Input
harmonics, Input current and leakage current)
The power supply will automatically recover from AC power loss and shall be capable of start-up under peak
loading at 85VAC.
Repetitive ON/OFF cycling of the AC input voltage shall not damage the power supply or cause the input fuse to
blow.
• Input Fuse
Not user serviceable. Fast Acting, high breaking capacity, ceramic fuse, 15A/250V rated
• Input undervoltage
The power supply is not designed to be protected against the permanent application of an input voltage
below the minimum specified. Avoid or protect against input undervoltage conditions that exceed 30seconds
duration.
2. DC OUTPUT
OUTPUT VOLTAGES
Output voltages are factory set at 12V, 24V, 28V or 48V +/-2% depending on the model.
The output voltage may be subsequently adjusted using the potentiometer ‘R3’ within the ranges listed below :-
12V model 9.6V ~ 14.4V
24V model 22.4V ~ 33.6V
28V model 22.4V ~ 33.6V
48V model 38.4V ~ 57.6V
On models fitted with output OR-ing diode, the maximum voltage shown above will be the voltage before the
OR-ing diode. The maximum adjustment voltage after the OR-ing diode will subsequently be reduced by up to
1V.
The main output voltage, auxiliary output voltage and output signals are isolated from the baseplate but not
isolated from each other. The remote on/off control is isolated from all outputs and baseplate.
REMOTE SENSE
Remote sensing, if required, can be connnected via the control signal connectors J2,J3 (pins 1 & 2) and
compensates for both +Ve and –Ve power line voltage drop. The remote sense terminals are internally
connected to +ve and -ve outputs via 100R/0.25W resistors and maybe left unconnected if not required. On
models fitted with output OR-ing diode, the internal connection is before the diode.
When using remote sense, the maximum power cable voltage drop should be limited to :-
+Ve Power cable 1.5V max (includes OR-ing diode drop on models fitted with OR-ing diode)
-Ve Power cable 0.5V max
OUTPUT OR-ING DIODE
CPFE500 series PSU maybe specified with or without integral OR-ing diode.
For models with OR-ing diode, the diode is fitted in the +ve output terminal of the PSU.
On 12V,24V & 28V models, the OR-ing diode is a schottky type rectifier.
On 48V models, the OR-ing diode is an ultrafast type standard rectifier.
CPFE500F Application Note Document Number : 61066 iss 2 Page 4 of 17
OUTPUT VOLTAGE TRIM
Output voltage can be adjusted within the normal range by connecting a resistance or applying external voltage
to the TRIM terminal (J2,J3 pin 8)
Take care not to exceed the normal voltage adjustment range as Overvoltage protection (OVP) may activate
and shutdown the PSU.
When increasing or decreasing the output voltage, observe the PSU maximum output power and current.
If required, remote sense can be used in conjunction with the output voltage trim function.
Internally, the TRIM terminal is connected to the voltage reference of the output voltage control amplifier – see
figure 1 below :-
Figure 1 – CPFE500 TRIM terminal Internal Circuit
The output voltage can be decreased from the adjusted set-point by connecting an external resistance between
TRIM and –S.
Do not connect external resistance between TRIM and +S, this will cause output instability.
Alternatively the trim terminal maybe driven by an external voltage, see figure 2 below.
Typically when left unconnected, the TRIM terminal voltage is 0.75V.
When applying an external voltage to the TRIM terminal, the main output voltage follows the formula :-
VOUT = VOUT
NOM
x (V
TRIM
/ 0.75) (where VOUT
NOM
is the output voltage setting with
TRIM terminal unconnected)
Figure 2 – Adjusting the output voltage using an external voltage source
CPFE500F Application Note Document Number : 61066 iss 2 Page 5 of 17
OUTPUT GOOD LED
A green LED adjacent to the output terminals provides a visual indication that output voltage is present.
The LED typically lights at the following output voltages :-
12V model 9V nom
24V model 19V nom
28V model 19V nom
48V model 31V nom
EFFICIENCY
A typical efficiency curve for a 12V model with OR-ing diode is shown below. This is the least efficient model.
24V, 28V & 48V models have typically 1~2% higher efficiency.
Models without OR-ing diode are additionally 1~2% more efficient.
The majority of dissipated heat is conducted into the baseplate, for the model shown, this dissipated heat is
~135Watts at full load / 115Vac dropping to ~110Watts at full load / 230Vac.
CAPACITIVE LOAD OPERATION
CPFE500 series has been tested with the following capacitive loads :-
12V model 42,000uF
24V model 18,000uF
28V model 18,000uF
48V model 10,500uF
Larger capacitive loads should be evaluated as required in the end application.
SERIES CONNECTION
It is possible to connect two CPFE500 psu outputs in series to provide higher voltage or split rail outputs.
Note that SELV outputs connected in series may create a non-SELV output.
PARALLEL CONNECTION
Parallel operation can be used to provide increased load current or achieve N+1 PSU redundant operation.
By connecting the PC terminal (J2,J3 pin 7) of each PSU together and setting the output voltages within +/-1%
the individual PSU’s will share the load current.
A maximum of 6 PSU’s of the same model can be connected in parallel.
Current balancing between units will have a some error and the maximum output current should be derated as
follows :-
2~3 units in parallel 90% of nominal output current
4~6 units in parallel 85% of nominal output current
Load current exceeding the limits above could result in operation of a PSU above it’s rated output capability.
Figures 3,4,5 below show typical wiring details for parallel connection of two CPFE500 psu’s.
For N+1 redundancy, specify CPFE models with integral output OR-ing diode, or alternatively fit an external ORing diode in the +ve output terminal of each PSU.
It is recommended to connect the –S voltage sense terminals of each PSU to a common load termination to
achieve the best balance of current between PSU’s.
The +S voltage sense terminal is optionally connected to the load to compensate for voltage drop in the +ve
power cable.
For N+1 redundant systems avoid connecting +S to the load as this creates a single fault condition for both
PSU’s.
Do not connect Trim terminals of PSU’s directly together. When using external voltage source at the Trim
terminal for paralleled PSU’s, insert a 10Kohm resistor in series with the voltage source for each PSU (see
CPFE500F Application Note Document Number : 61066 iss 2 Page 6 of 17
Figure 5). Additional voltage drop across this 10Kohm series resistor will change the voltage programming
calculation – refer to Figure 1. For N+1 redundant systems, individual voltage source circuits would be advisable
for each PSU to maintain the system redundancy.
Figure 3 – Basic Parallel connection Figure 4 – Parallel connection with adjusted output
Figure 5 – Parallel connection with adjusted output from voltage source
Loading...