Low temperature drift

Carefully selected components, improved circuit design, and heat dissipation based on the forced air cooling design have achieved a low- temperature drift of 100 ppm/°C (constant voltage characteristic) and 300 ppm/°C (constant current characteristic).

Quick transient response

Since the Error Amplifier has a characteristics of wide frequency bandwidth, stable gain, less phase shift and high loop gain, the PAN-A series is equipped with a highly stable and low output impedance as well as quick response to sudden change of the load.

(Typical response time is 50 μs)

Application

Incorporates a wide range of functions capable of systematization, including analog signal- or computer- (GPIB) based remote control, remote sensing, and master-slave-control serial and parallel operations.

(The PAN350-3.5A and PAN600-2A cannot be operated in series.)

Remote-control using external voltage

Remote-control using external resistor

Computer Control

To control the power supply from a PC via a GPIB interface, connect a PIA4800 seriespowe rsupply controller to a PAN-A series power supply.

* Combine the PIA4810 power supply controller and OP01-PIA or OP02-PIA cont rol board for two-channel analog control with the PIA4800 series. Since the PIA4810 controller incorporates four control boards, up to eight channels of DC power supplies or loads can be controlled.

Master-slave control of parallel operation

(This control is possible only for parallel-connected units of the same model.)

• The current capacity can be increased by connecting a multiple number of units of the same model in parallel. Output control can be perfor med by a master unit.
• Use only one master unit to perform remote sensing, remote control, and output on/off control

* For one master unit, a maximum of two slave units can be connected in parallel.

Master-slave control of series operation

(This control is possible only for series-connected units of the same model.)

• The output voltage can be increased by connecting a multiple number of units of the same model in series. The unit on the top (i.e., the positive side) plays the role of master, and can control the output of the slave unit(s).
• The example shown above is a dual tracking power supply that can vary positive and negative voltages simultaneously

* The number of slave units to be connected in series is deter mined bythe rated output voltage and isolation voltage of each unit.
Taking the PAN35-10A as an example for series connection: Since the rated output voltage is 35V, and the isolation voltage is ± 250V, 250/35 = 7.1, i.e., up to 7 units including the master unitcan be connected in series.

Note: PAN350-3.5A and PAN600-2A do not offer master-slave control and serial operation functions.

Remote sensing

• This is a method used to compensate for the voltage drop caused by the cable resistance between the power unit and the load and contact resistance. The problem of voltage drops becomes more serious as the current becomes larger. By turning on the “Sens” switch at the rear panel and transferring the voltage sensing point to the load , a voltage drop of up to 0.6V can be prevented on one side.
  Note: For the sensing function in 16V models, the maximum output voltage of this series is 105% of the rated voltage. Since the maximum out put voltage of the 16V models is 16.8 V, an attempt to compensate for 1.2 V (0.6 V for one way × 2), the full-compensating voltage, will disable output of the rated voltage. In this case, use wires that have a larger cross- sectional area with less voltage drop, so that voltage drops are 0.4V or less one-way.
• Connect an electrolytic capacitor with a capacity of a several thousand to several tens of thousand of microfarads to the load end, paying attention to the polarity and making the lead wires as short as possible. The reasoning here is as follows. A long cable to the load has nonnegligible inductance, which raises the output impedance of the power supply unit to the load. A large capacitance connected to the load end can prevent this. Particularly when dealing with a load like an inverter, which t u r ns the current on and off with high frequency, connect a capacitor with a capacity larger than several thousand microfarad using the shortest possible lead wires.

Overvoltage protector (OVP)

If an over voltage is generated by an operating error or accident, the OVP instantaneously (Operating time: 50 ms or less ) shuts down the power switch circuit protector, and protects the connected load. (Type 0 and Type I2 models employ a gate block system, and shut down their rectification circuits.) Since the OVP used in the PAN-A series is of a preset design, the operating voltage can be preset by pressing the preset knob on the panel, while looking at the voltmeter. The operating voltage can be checked without interrupting the OVP operation even during aging.

Overheat protection circuit

This circu it functions to turn off the power switch, if the temperature of some of the main components in the equipment rises higher than a specified value. A thermal fuse incorporated in the main- or sub-transformer further improves safety performance.

Voltage detection circuit

If the smoothing electrolytic capacitor voltage rises above a specified level owing to an operating error involving the remote selection switch inside the panel or to a failure of the rectification circuit, the voltage detection circuit functions to instantaneously shut down the rectification circuit.

Surge absorber

This protect the power supply unit from surge currents generated in the power line by lightning.

Reverse connection prevention circuit

This circuit protects the power supply unit even if a reverse polarity voltage is applied to the output terminals.

Overcurrent detection circuit

Using a comparison amplifier, this detection circuit constantly monitors the output current. It prevents a current from increasing beyond the rated value in the event of an over-input caused by remote control, and also prevents overcurrents caused by misoperation of the remote control selector located inside the panel.

Load with accumulated energy, such as a battery

When connecting a load with accumulated energy, such as a battery, to the PAN-A series output, a large current may flow from the load to the inter nal capacitor through the output control circuit protection diode. This current may burn internal components or shorten the load’s life. In such a cases, therefore, connect a reverse current protection diode between the power supply unit and the load as shown below.

When the load current has peaks or a pulse waveform

In the case of a digital or a motor driving circuit, a load current waveform will instantaneously reach the rated current range if the peak value exceeds the rated value, even if it is within the rated value on the meter indication (mean value). If so, the output voltage will drop and appear unstable. The basic remedy is to increase the output current (i.e., increase the current preset value or current capacity). However, if the pulse width is narrow or the peak value is low, it may prove effective to connect a large-capacitor to the load end.

Inductive load

The counter electromotive force generated by turning on and off of the power supply, or changing the voltage setting is shunted by protection diode D1 inserted in parallel with the out put so that the power supply is not damaged.

When pulse noise generated from an inductive load is impressed at the same polarity as the power supply, protect the power supply by inserting diode D2 in series with the power supply and inserting a noise prevention CR absorber across the switch.

When the output is turned On and off with a mechanical switch

When a DC output of 100V or more is opened and closed with a switch, arc discharge, etc. will cause the switch contacts to noticeably wear and generate noise. This noise may enter the power supply differential amplifier through the load line and cause the output to become unstable. Take noise counter measures by inserting a CR absorber near the contacts, the same as for an inductive load.

When performing remote sensing, always turn the sensing line on or off simultaneously.

Rush Current

When turning on the power, a rush current may flow, depending on when the power is turned on. Such rush currents are caused by magnetic saturation of the transformer core material. Theoretically, if the power is turned on near the phase angle 90°(π/2) of the voltage waveform, no rush current is generated. If the power is turned on at a timing corresponding to the phase angle 0°(zero cross), however, a max. current is generated. This transient phenomenon is shown below. In practice, however, the presence of a rush current is determined by the hysteresis character istic of the B-H curve of the core material, the direction of residual magnetic flux upon switch-off, and/or the impedance of the AC line to which the PAN-A series is connected. If the power is turned on simultaneously for a multiple number of the PAN-A series units, check that the AC line capacity or the switch board capacity is sufficient.

• Typical (max.) rush current value for the PAN-A series
  (Half wave width of current waveform: approx. 5 ms)

Negative voltage

With the OUTPUT switch set to OFF, a negative voltage of approx. 0.6V is applied to the output when the current setting knob is turned completely cou nterclock wise. This voltage acts to generate approx. 10mA of reverse cur rent through the load. The PAN-A series may be inadequate for applications in which the load should be kept free from serious influence by such a reverse current.

Output terminals on the front side

The output terminals on the front side are auxiliary output terminals. These terminals may not satisfy the specification. To satisfy the specification, use output terminals on the rear panel. Be sure to use the attached terminal cover for models with rated output voltage higher than 55 V.

* PAN16-50A is not equipped with this feature.

Output wires

The sectional area, current capacity, and resistance of these wires are as shown below.