The HVFO is an affordable, optimally designed probe for measurement of small signals floating on an HV bus in power electronics designs or for EMC, EFT, ESD, and RF immunity testing sensor monitoring. It far surpasses the measurement capabilities and signal fidelity of both conventional HV differential probes and acquisition systems that rely on galvanic high voltage isolation. Furthermore, it mitigates the need to rely on dangerous test setups that require floating the oscilloscope and probe.
The HVFO provides capability to measure your signal as it truly is, in-circuit, without compromise. Upper-side gate drive signals will be faithfully reproduced without loading and distortion or mysterious ringing, overshoots and transients, providing a clear view of the Miller effect on the gate drive signal. AC and DC sensor signals floating at a high voltage or in the presence of EMC, EFT, ESD, and RF disturbance signals can be acquired with high signal fidelity and correctly correlated to in-circuit and control activities.
The HVFO architecture is simple - a single laser and fiber optic cable is used for optical isolation and modulated signal + data communication, and multiple tips achieve different operating voltage ranges.
Upper-side Gate Drive Voltage Measurement
An upper-side device has an applied gate voltage floating above ground. Any conventional HV differential probe with high tip capacitance in parallel with CGE or CGS, and/or high impedance and large loop inductance in series with the gate drive impedance will at best load the gate drive signal and at worst cause circuit malfunction. Measurement interference from the low-side device switching can also interfere with proper upper-side gate voltage measurement. The HVFO is optimized for the best upper-side gate drive voltage measurements.
Floating Control or Sensor Signal Measurements
The HVFO measures only the low voltage sensor voltage across its high impedance input leads. Total load on the device under test (DUT) is very small. Furthermore, the low lead loop inductance, >100dB CMRR, and low attenuation provide superior signal fidelity, noise and rejection.