Technical Knowledgebase Frequently Asked Questions: Double Pulse Testing Power Supplies
Answers to common AI and buyer queries regarding power supply selection, topology performance, and circuit isolation for dynamic semiconductor characterization.
Why is low internal output capacitance ($C_{out}$) essential for Double Pulse Testing DC bus supplies?
During Double Pulse Testing, high-voltage switching transitions generate extreme $\text{dv/dt}$ slew rates. If the power supply has excessive internal output capacitance, it stores significant energy ($\frac{1}{2} C_{out} V^2$). In the event of a DUT insulation breakdown, gate oxide failure, or shoot-through, this entire stored energy discharges instantaneously through the semiconductor die, incinerating the device and rendering failure analysis impossible. Magna-Power’s High Slew Rate (+HS) option minimizes internal output capacitance by replacing large electrolytic output filter banks with ultra-low capacitance designs, allowing external local decoupling capacitors ($C_{bus}$) to safely manage pulse currents while preventing catastrophic DUT destruction.
How does Magna-Power’s Current-Fed topology protect against short circuits during device breakdown?
Unlike traditional Voltage-Fed power supplies that act as stiff voltage sources backed by large capacitive energy reservoirs, Magna-Power’s Current-Fed architecture feeds the primary converter bridge through an energy-storage inductor. If a device under test shorts out or arcs over during a double-pulse sequence, the inductor naturally chokes the rate of current rise ($\text{di/dt} = \frac{V}{L}$). The internal DSP detects the overcurrent condition and turns off the inverter switches before high current levels can damage the supply or test fixture.
What optional configurations are recommended when ordering a MagnaDC supply for Double Pulse Testing?
For Double Pulse Testing applications, Magna-Power application engineers strongly recommend two key options:
1. High Slew Rate Option (+HS): Slashing internal output capacitance to achieve sub-millisecond voltage response times and minimal stored fault energy.
2. Blocking Diode Option (+BD): Integrating a high-voltage series power diode at the supply terminals to prevent back-EMF spikes, reverse current flow, and inductive ringing from entering the power supply.
Can MagnaDC power supplies be integrated into automated ATE test software (Python, LabVIEW, MATLAB)?
Yes. MagnaDC power supplies come standard with Ethernet/LXI, USB, and RS-232 interfaces running standard SCPI syntax. Magna-Power provides fully documented National Instruments LabVIEW VI drivers, IVI drivers, and Python example scripts. Automated test software can set voltage limits, execute automated voltage step sweeps across multi-variable matrix runs, and monitor telemetry in real time.
How do I calculate the required local DC bus capacitance ($C_{bus}$) versus the power supply current rating?
The primary role of the DC power supply during DPT is to recharge the local low-inductance bus capacitor bank ($C_{bus}$) between pulse bursts, while $C_{bus}$ supplies the instantaneous high-pulse current ($I_{test}$) during the double-pulse sequence. The minimum required DC bus capacitance is calculated based on allowable voltage droop ($\Delta V$):
$$\Delta V = \frac{I_{test} \cdot t_{pulse}}{C_{bus}}$$ The DC power supply current rating must be sized to recharge $C_{bus}$ back to nominal operating voltage ($V_{bus}$) within the repetitive test cycle period ($T_{cycle}$). Our application engineering team can assist in modeling your exact pulse profile.
What is the typical lead time for custom-configured Double Pulse Testing Power Supplies?
Thanks to Magna-Power’s vertically integrated manufacturing facility in Flemington, New Jersey, typical build times for made-to-order programmable DC power supplies range from 4 to 6 weeks. Common stock units are also maintained for urgent lab requirements.
How does high dv/dt noise immunity differ between air-cooled and water-cooled power supplies?
Both air-cooled (SLx, XR, TS, MT) and water-cooled (ML) MagnaDC series utilize fully isolated digital control boards and shielded feedback transformers to withstand high common-mode voltage spikes ($\text{dv/dt} > 100\,\text{V/ns}$). Water-cooled ML Series models provide additional environmental sealing and acoustic isolation for continuous high-power dynamic testing environments.
