Manual OC32/NG
VPEB
Control your Miniature World
Page 16 of 48
Version 1.0 – December 15
th
, 2017
2017 Leon van Perlo
OC32
internal
power
GND
GND
Vp1
GND
Vp2
PWR
Jp1
Jp2
Drivers
16..31
Drivers
0..15
from the central PWR supplied to K1, allowing you to use separate power supplies for your
devices and the OC32 itself. Per OC32/NG you can even have two different power supplies
for devices and a separate one for the OC32 itself.
4.4.3
Providing power to the OC32/NG via K5A or K5B
The power you supply to K1 will be forwarded to Vp1 and Vp2 on the K5 connectors. You can
also do it the other way around: While the power jumper JP1 is installed, power supply
connected to Vp1 on K5A will be forwarded to PWR and power the internal electronics of
your OC32/NG. Similar, while the power jumper JP2 is installed, power supply connected to
Vp2 on K5B will be forwarded to PWR. In these cases you can leave K1 unconnected. You
will have all OC32 connections at one side, with the exception of the connections for
communication.
Note that, while both JP1 and JP2 are installed, Vp1 and Vp2 are automatically connected.
The schematic is essentially as indicated in figure 7.
Fig 7: Power distribution schematics
4.5
5V
Internally, the OC32 operates on a supply voltage of 5V. The OC32 obtains this from the
supply voltage PWR, delivered on K1 or delivered on Vp1/Vp2 through jumpers Jp1/Jp2. The
OC32 itself ensures an accurate stabilization, so you don’t have to worry about that
yourself.
In rare instances, you may want to have access to the internal 5V system of the OC32.
If you make use of so-called 5V outputs (see further on), then the power for these outputs
is obtained from the internal 5V. If you use the outputs to their load limit
and at the same
time
, the available supply voltage on PWR is high (e.g. higher than 15V), then the stabilizer
on the OC32 can become quite hot. The most obvious solution in this case is to split Vp and
PWR and feed the OV32 from e.g. a 7-9V power supply.
Alternatively
you may provide an
external 5V directly, especially if it is already present in close proximity of the OC32, very
well stabilized and it has an efficient regulator.
Also in some cases you may need a 5V connection, e.g. if you want to drive LED’s,
connected with their cathode to an output configured for 5V operation (see paragraph …).
You then can make your own 5V supply, or derive it from the OC32.
On the OC32/NG, the 5V is no longer available by default on K1, as was the case with the
previous models. The reason is that this 5V is directly connected to the OC32 CPU. Any
Voltage over 5.1V or under 0V applied to this interface will cause severe damage to the
OC32. Since the 5V interface is hardly ever needed, it has been removed to protect the
OC32 from unintended errors.
Control your Miniature World
VPEB
Manual OC32/NG
2017 Leon van Perlo
Version 1.0 – December 15
th
, 2017
Page 33 of 48
The resistor array shall be a DIL16 version with individual resistors. The value of the
resistors can be selected as required but preferably do not go below 100
Ω
. In most
connection examples a reasonable value is suggested
A 5V output in this configuration can supply/sink 40mA, however
Take care:
•
The total load of all 5V outputs on ports 0..15 shall not exceed 100mA;
•
The total load of all 5V outputs on ports 16..23 shall not exceed 100mA;
•
The total load of all 5V outputs on ports 24..31 shall not exceed 100mA.
In this case the power for the outputs is retrieved by the processor from the electronics
power supply. If a non stabilized power is connected to PWR and the OC32 has to stabilize
it, the PWR should be modest. The difference in voltage multiplied by the current is
converted into heat. PWR has to be at least 7V and if the 5V outputs require much power
the adagio is the lower PWR the better”.
6.1.5
OC32-ADM/SI (4,8A power sink-driver)
Use this driver when the required current is larger than the 500mA supported by the
standard driver. A load is connected between Vp and the ADM output. The current flows
from the positive voltage (Vp) through your load to the output and on the OC32 via the ADM
to GND/0V.
Each output can provide 4,8A as an absolute maximum
Take Care: this is a peak current. Continuous load shall be kept below 2A per channel
and below 3A total current for each driver module.
There is no current limitation in the OC32, so you have to take care of that
6.1.6
OC32-ADM/SO (4,8A power source-driver)
Use this driver when the required current is larger than the 500mA supported by the
standard source driver. The load is connected between the output and GND/0V. The current
flows from positive voltage (Vp) via the ADM on the OC32 to the output of the OC32 and
then via your load to GND/0V.
Each output can provide 4,8A as an absolute maximum
Take Care: this is a peak current. Continuous load shall be kept below 2A per channel
and below 3A total current for each driver module.
There is no current limitation in the OC32, so you have to take care of that
6.1.7
OC32-ADM/MX (4,8A multiplexer)
This driver offers 4 sink-driver ports and 4 source-driver ports. It is intended as a module to
drive a matrix of turnouts. One MX can drive 8 turnouts (2 solenoids each), two MX’s
together drive 32 turnouts (2 solenoids each).
The MX can provide 4,8A as an absolute maximum. This is a peak current, but since the /MX
is a matrix driver, this will hardly be a problem in practice.
6.1.8
OC32-ADM/FH (4,8A Full H-bridge)
This driver is the high-current version of the sink+source driver combination as described in
section
6.1.3. Same conditions apply.
