Frequently Asked Questions
What is a high voltage power supply?
In general terms a high voltage power supply is a device that is capable of generating a user-defined high voltage output, normally DC, through a conventional mains voltage input or by a DC input, by employing power conversion topologies and technologies.
The mains input can be of any standard voltage available in AC or DC form, for example, 220VAC/50Hz or 24VDC input.
The mains input selection depends on the device installation, site facilities and application needs. Usually, power supplies with the output power of over 2000W (2kW) are normally 3 phase mains (415 VAC) input due to increased input current demand.
The output(s) of these high voltage power supplies can be either Positive or Negative with reference to the ground potential provided.
Proper grounding of a high voltage power supply is very important for its continued safe operation, as the ground wire is used as a return path in the inter-connection between the power supply and the load.
Since the power supply output can be of a lethal voltage(s), it needs to be fitted with the applicable fail-safe and interlock protection circuitries.
How does a high voltage power supply work?
Modern high voltage power supplies employ power conversion topologies based on SMPS technology, to convert the low-frequency low voltage input to high voltages at the output. The principal idea of SMPS is to achieve this conversion utilizing high-frequency switches, such as MOSFETs, and a high-frequency transformer.
The high voltage power supply transforms the rectified and filtered DC bus voltages, gained by rectification of the mains input, to high-frequency AC with the help of high-frequency switches. These switches are usually switched above 20kHz and are controlled by varying the duty-ratio, to regulate the power transfer.
This high-frequency AC is further amplified to higher voltages by a high-frequency transformer. This transformer is the prime source of galvanic isolation. The stepped-up voltages are rectified, multiplied, and filtered at the secondary of the HF transformer to provide the desired voltage levels as the output.
Complex control circuitry is implemented in a high voltage power supply which enables the user to control the output as per the user demand. This circuit includes the fail-safe protection circuitry and the switching frequency drive to the switches.
