• DOKF series
  • DOKF series

DOKF series

Sequence Function Installed High Speed Response Bipolar Power Supply

  • Max Voltage: ±20V to ±80V
  • Max Current: ±5A to ±20A
  • Max Power: 400W
  • Ultimate in accurate sequence operation

Four-quadrant bipolar power supplies are developed up to followings.

DOKF series are four-quadrant power supplies possible to source and sink current. They can be applied widely according to the usage from transient response test to various evaluation tests as they realize high speed response of DC to 120 kHz (at constant voltage mode) and can generate basic waves such as sine wave, rectangular wave and programmed waves by embedded function generator. And, as they provide also the high resolution sequence function as standard, you can program output patterns in detail. Moreover, as their generation of wave and setting sequence can be made all with the simplified operation on the front panel, you can make full use of various functions easily.

Main features

  • Superior visibility and operability by using color liquid crystal display.
  • High speed of DC to 120 kHz is realized.
  • Four-quadrant behavior able to source and sink current.
  • It is possible to generate non-distortional wave such as sine wave, rectangular wave.
  • It is possible to set and operate high performance sequence in 1024 steps.
  • There are 2 modes of DC and AC+DC and each of them can be set individually.
  • 2 modes operation of CV (constant voltage) and CV (constant current) are applicable.
  • It is possible to connect maximum 3 power supplies in parallel (synchronized trigger) by coinciding accuracy of frequency (synchronized clock) in synchronized operation.
  • GPIB, USB and RS-232C interface are equipped as standard.
  • It is possible to output voltage/current in 16 bits and programmed waves of resolution of 1024 in one cycle. (optional control software)

Four-quadrant Behavior

  • Vo max: Rated output voltage
  • Io max: Rated output current
Four-quadrant Behavior legend

Output control by remote control with communication

Output control by remote control with communication

Main Applications

  • To drive capacitive loads such as capacitor.
  • To drive inducible loads such as coils and transformers.
  • Tests of various motors.
  • Evaluation of solar cell panel related equipments such as power conditioners.
  • Voltage fluctuation tests for automotive electrical components. ETC.

This product is not designed for charge and discharge of battery. Please contact nearby sales if unit is used for charge and discharge application.


We can manufacture other specifled voltage,current and frequency band written as followings.

Model Output Frequency Bandwidth [kHz (-3 dB)]
Maximum output voltage [V (rms)] Maximum output current [A (rms)] Maximum output power [W] At CV mode At CC mode
DOKF20-20 ±20 ±20 400 DC to 120 DC to 60
DOKF40-10 ±40 ±10
DOKF60-6.7 * ±60 ±6.7 DC to 50
DOKF80-5 * ±80 ±5

* They are available in the near future. Please contact our sales staff for detail.


Basic Wave Generation Function

DOKF is equipped with a built in function generator that produces basic waves such as sine, rectangular and triangle waves. Frequency range can be set between 0.01 Hz and 120 kHz. Easy adjustments/edition of amplitude, initial phase (for sine wave), phase shift (for sine wave), and duty ratio (for rectangular/triange wave) are possible. DOKF has special feature of “soft start” and “soft stop” which enable to program initial rise and fall characteristics of the output.

Starting phase Starting phase
Soft start Soft start

AC Volt/current sweep, frequency sweep

Soft stop Soft stop

DC Volt/current ramp


Power activation test, various start-up tests of motor, flunctuation test of wave shape, etc.

Sequence functions

DOKF is equipped with sequence function that can program parameters such as step length, step amplitude ramp, DC voltage and current ramping, AC voltage and current ramping, frequency sweep, AC superposition, step jump, and jump times. These useful functions help to program the desired waves in very flexible manner, resulting to support efficient laboratory and research works.

Complex sequence can be created easily with teh intelligible display.
Sequence functions 1
Sequence functions 2
  • Step setting length 0.1 ms to 1000 h (resolution of 0.1 ms)
  • Maximum 1,024 steps per program.
  • Maximum 64 programs can be stored in memory for each CC/CV operation
  • Program repeat can be set by “endless repeat” or “1 to 10,000 times”
  • Multiple programs can be converted to activate
Image of Program
Image of Program

Sequence functions help to create complicated waves like below to be simply and easily edited.

Pulse current variation Pulse current variation
Ripple current superpose Ripple current superpose
AC voltage variation AC voltage variation
DC voltage cutoff DC voltage cutoff


Test for motors, pulse power supply and various evaluation.

Measurement functions

DOKF is equipped with measurement function that can measure DC value, AC RMS value, and Max/Min value, likewise, it is possible to automatically measure wide range bandwidth from DC to 120 kHz. There are 4 parameters which are simultaneously displayable, each of these parameters are individually programmable. As this measurement is standard feature, no option needs to be purchased. This sophisticated feature will reduce time for editing output waves and bring up work efficiency.

Measurement functions 1
Measurement functions 2

Synchronized Operation

The following DOKF operations are available for up to three units.

Synchronous Trigger

Through a single operation of the master unit, it is possible to match the output timing of ON/OFF in one or two slave units. In turning the output on, the output starting gap between the master and the slave is less than 0.5 μs

*To use this function, please purchase "Dedicated cable for synchronous trigger" of 2 meters separately.

Synchronous Clock

By providing the clock input of 10 MHz, the individual difference between the oscillators installed on each unit is removed (In the case of this, there are a few ppm up to several tens ppm in general). What is more, frequency accuracy and sequence-step time are completely unified through the operation.

Moreover, the product is also available for setting the phase shift difference for sine wave toward each unit.
(*Please prepare the coaxial cable on both ends of BNC connectors which is not included but required for synchronous clock.)

*When the slave unit is required to synchronize in accordance with the waveform set by the master unit, -LMs option must be taken (in master/slave control).
Note that the time synchronized operation is not available if using the master/slave control.

Synchronized Operation
Ex.) Setting of phase difference of 90 degrees at sine wave output
Other functions:
Protection Function (Cut-off, Individually Settable Limiter Protection), Key Lock Function and Switching CV/CC, Memory Function, these are installed as standard.



  1. Display: Display various settings and measurements.
  2. OUTPUT switch: ON/OFF for output
  3. Rotary encoder: Change value
  4. POWER switch: ON/OFF for main power
  5. CANCEL switch: Cancel settings
  6. ENTER switch: To confirm and key in
  7. CV/CC switch: Switchover CV/CC mode
  8. Memory switch: Switchover memory screen
  9. Setting/Storage switch: Make to setting change menu, store memory
  10. Protection switch: To switch protection setting menu
  11. Shift up switch: Shift up each setting items
  12. Shift down switch: Shift down each setting items
  13. Sequence switch: Use for switchover of sequence screen or interrupt or restart of sequence operation
  14. Shifting left switch: Shift digits of settings to left
  15. Shifting right/LOCK switch: Shift digits of settings to right and also use key lock function


-LMsm, -LMss: Master-slave Control (parallel operation)

Maximum 3 units including master unit are hooked.

("-LMsm" for the master unit and "-LMss" for slave units. Please order required number of units. Every master unit and slave units are exclusive use. When change the combination of master-slave, they should be readjusted in our shop.) (If you take this option, the synchronized operation is not available.)

-LRa: The front panel attachable to the 19-inch rack of EIA or JIS

The front panel becomes the panel attachable to the 19-inch rack of EIA or JIS standards. Dimension of the front panel is modified in case attached. Please consult our sales staff.

(It is impossible to support the main unit only with these brackets. Please utilize always a sole plate or angle bars to support the unit weight.)

-LCk: CC-Link Interface Board

It enables digital remote control via net work of CC-Link.


AC input cable


125 V/15 A 2.5 m



*Please use appropriate AC cable.

Tech Notes

For Capacitive Load

When a capacitive load is more than 100 pF (including a stray capacitance of output wire), the resonance in the output may occur. In that case, install 100-ohm (@0.1 μF) to 1000-ohm (@1000 pF) of high voltage resistance in the output in series. Please note that the frequency band will be limited as the formula written in the right figure when an amplifier is used with a capacitive load.
In addition, when an amplifier is used for the use such as a corona discharge, the current which is higher than rating will flow and it will affect the amplifier badly. In this case, as well as the time to use an amplifier with a capacitive load, please install the output resistance and limit the current.

* Please avoid continuous inputting of high frequency signal which reduces output frequency of an amplifier. An amplifier will be broken because of increase of internal loss.

This image explains frequency band when a capacitive load is connected.

Read more

For Induced Loads

At CC mode, oscilliation may be caused by inductance of induced loads.
If so, please connect C-R straight circuit between output terminals as not to cause oscilliation.


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Bipolar power supplies/High voltage Amplifiers