Download Using Omron Power Supplies to Make Positive and

Using Omron Power Supplies to Make
Positive and Negative DC Output Voltage
Scope
Positive and negative reference voltage can be required to properly power analog circuits or
PNP/NPN devices. The positive and negative voltage can be created by wiring two power supplies
together in a series configuration. Proper sizing and wiring of the power supplies will be
demonstrated in this Technical Note.
Background
It is generally rare to need a negative voltage. Negative voltages can be required for sensors (such
as load and torque sensors), PLC’s, PMOS switches, operational amplifiers (OP-Amps), crazy
physics experiments, and more. When the outputs of a power supply are separated or floating this
enables the creating of positive/negative outputs using two power supplies. Refer to the Omron
power supply data sheet to determine if series operation or connection is permitted.
The following table shows the Omron models that support series connection of outputs:
Model
S8VK-G
S8VK-C
S8JX
S8VS
S8VM
Power Rating
All Models
All Models
All Models
60, 90, 120, 180, 240, 480 Watts
All Models
Rated Output Voltage
5, 12, 24, 48 VDC
24 VDC
5, 12, 15, 24, 48 VDC
24 VDC
5, 12, 15, 24 VDC
The connection of positive/negative output is similar to series connection but power supplies of the
same voltage and wattage should be used for correct wiring.
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Cat. No. TN-POWER-SUPPLY-POS-NEG-VOLTAGE
01/20/2014
Technical Note
Application
First connect Power Supply 1 (PS1) and Power Supply 2 (PS2) in a series connection. (Figure 1)
Figure 1 Series Connection
Second, the positive and negative voltage is created by tapping off the circuit between the two power
supplies: (Figure 2)
Figure 2: +/- Voltage
This creates the output voltage at the same current level of both power supplies. If two 60 Watt, 24
VDC, 2.5 amp output power supplies are used, the creation of a +24 VDC and -24 VDC output is
obtained. For electronic circuits a +5 VDC and a -5 VDC output may be required. As shown in figure
3, load 1 is positive voltage for control circuit and load 3 is a negative voltage to power transistors or
operational-amplifiers in the same system.
Load 1
Load 2
Figure 3: Loads connected +/- Voltage
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Cat. No. TN-POWER-SUPPLY-POS-NEG-VOLTAGE
01/20/2014
Technical Note
Additional Information
If the full voltage of the 2 series connected power supplies is used by another load connect bypass
diodes (D1 & D2) as shown: (Figure 4)
Figure 4: Bypass Diodes
Use Diode
Type: Schottky barrier diode
Dielectric strength (Vrrm): Twice the rated power supply output voltage or higher
Forward Current (If): Twice the rated power supply output current or higher
Conclusion
You can create +/- voltage source by using two Power Supplies. This is an easy and inexpensive
way to properly power analog circuits, microcomputer boards, IC chips or other circuits that require a
voltage reference. Refer to the series operation of the power supplies used to determine the proper
wiring connection.
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Cat. No. TN-POWER-SUPPLY-POS-NEG-VOLTAGE
01/20/2014