Description
Instek PSW 40-81
Programmable DC power supply
Voltage: 0-40V
Current: 0-81A
Maximum power: 1080W
Programmable DC Power Supply (0-40V / 0-81A / 1080W)
The PSW-Series is a single-output multi-range programmable switching DC Power Supply covering a power range up to 1080W. This series of products include eighteen models with the combination of 30V, 40V, 80V, 160V, 250V, and 800V rated voltages and 360W, 720W and 1080W maximum output powers. The multi-range feature allows the flexible and efficient configuration of voltage and current within the rated power range.
The chart below provides an overview of the PSW series. These can also be run in series (2 units maximum) and parallel (3 units maximum) – please see page 3 of this link for more information on performance characteristics.

Voltage Current Power
PSW 30-36 0-30V 0-36A 360W
PSW 30-72 0-30V 0-72A 720W
PSW 30-108 0-30V 0-108A 1080W
PSW 40-27 0-40V 0-27A 360W
PSW 40-54 0-40V 0-54A 720W
PSW 40-81 0-40V 0-81A 1080W
PSW 80-13.5 0-80V 0-13.5A 360W
PSW 80-27 0-80V 0-27A 720W
PSW 80-40.5 0-80V 0-40.5A 1080W
PSW 160-7.2 0-160V 0-7.2A 360W
PSW 160-14.4 0-160V 0-14.4A 720W
PSW 160-21.6 0-160V 0-21.6A 1080W
PSW 250-4.5 0-250V 0-4.5A 360W
PSW 250-9 0-250V 0-9A 720W
PSW 250-13.5 0-250V 0-13.5A 1080W
PSW 800-1.44 0-800V 0-1.44A 360W
PSW 800-2.88 0-800V 0-2.88A 720W
PSW 800-4.32 0-800V 0-4.32A 1080W
Multi range operation
When the power supply is configured that the total output (Current x Voltage output) is less than the rated power output, it functions as a typical Constant Current (C.C) and Constant Voltage (C.V) power supply. However, when the power supply is configured such that the total output power (Current x Voltage Output) exceeds the rated power output, the effective output is actually limited to the operation area of the unit.
CC/CV priority
The CV/CC priority selection of the PSW-Series is a very useful feature for DUT protection. The conventional power supply normally operates under CV mode when the power output is turned on. This could bring a high inrush current to the capacitive load or current-intensive load at the power output-on stage. Taking the I-V curve verification of an LED as an example, it becomes a very challenging task to perform this measurement using a conventional power supply. With the LED connected to a power supply under CV mode as the initial setting, when the power output is turned on and the voltage rises to the LED forward voltage, the current will suddenly peak up and exceed the preset value of current limit. Upon detecting this high current, the power supply starts the transition from CV mode to CC mode.
Though the current becomes stable after the CC mode is activated, the current spike occurred at the CV and CC crossover point may possibly damage the DUT. At the power output-on stage, the PSW-Series is able to run under CC priority to limit the current spike occurred at the threshold voltage and therefore protect DUT from the inrush current damage.
Adjustable slew rate
The PSW-Series has adjustable slew rates for the level transition of both Current and Voltage. This gives the PSW-Series power supply the ability to set specific rise time and fall time of the Voltage and Current drawn from the power supply to verify DUT performance during the Voltage / Current level transition. The feature also provides the benefit to slow down the voltage transition at the power output-on to protect DUT from inrush current damage. This is especially useful for the test of heavycurrent-drawn devices like capacitors.
Series and parallel connections
To increase power output capacity, the PSW-Series could be connected in Series mode to perform double voltage rating or in parallel mode to perform triple current rating for each model. With the Multi-Range feature and Series/Parallel connection capability, the PSW-Series is a high power density and cost-effective equipment for the tests of DC power modules, batteries and components in a broad power range.

1. Voltage Knob
2. Current Knob
3. Output Key
4. Function Keys
5. USB A Port
6. Display
7. Cover Panel
8. Power Switch
9. Analog Control Connector
10. USB B Port
11. Output Terminal (+)
12. Sense Terminal(+/-)
13. Output Terminal (-)
14. Fan
15. AC Input
16. LAN Port