1Overview
The PVX-4150 is a high voltage pulse generator from the Directed Energy Division of Berkeley Nucleonics. It generates clean, fast pulse waveforms to 1,500 V and is optimized for high impedance capacitive loads. That suits it to driving extraction grids and deflection plates for the electrostatic modulation of particle beams in time-of-flight mass spectrometers and accelerators.
The same robust design serves a wide range of pulsing and gating tasks. Typical loads include power tube grids, Pockels cells and Q-switches, acoustic transducers, microchannel plates, photomultiplier tubes, and image intensifiers. The exceptional pulse fidelity of the PVX-4150 improves rather than limits the performance of the system around it.
The instrument is fully self-contained. All control and protection logic, support power, energy storage, and the output network are built in. It connects directly to the load and does not need series or shunt resistors, an impedance-matching network, or an external capacitor bank. To run, it needs a TTL gate signal, a user-supplied high voltage DC source, and an optional second supply when the output is biased away from ground.
2How It Works
The PVX-4150 is a direct-coupled, air-cooled, solid-state half-bridge, often called a totem-pole output stage. Two high voltage switches sit in series between a user-supplied high rail (VHigh) and low rail (VLow). The gate decides which rail is connected to the output. When the gate is high, VHigh is switched to the output; when the gate is low, VLow is switched to the output. The pulse amplitude is therefore set by the difference between the two supply voltages, and the pulse width and repetition rate are set by the gate.
Driving the output from both rails gives flexible polarity. With VLow at ground, the unit produces positive pulses from ground to +1,500 V. With VHigh at ground, it produces negative pulses from ground to −1,500 V. To make a negative-going pulse from a normally-high baseline, invert the gate so the input sits high until the unit is pulsed; when the gate goes low, VLow connects to the output and the result is a negative-going pulse. The output can also be offset from ground by setting both supplies, anywhere from −1,500 V to +1,500 V, with a maximum supply differential of 1,500 V.
The totem-pole topology gives equally fast rise and fall times, low power dissipation, and virtually no overshoot, undershoot, or ringing. Over-current detection and shut-down circuitry protect the generator against arcs and shorts in the load or the interconnect cable.
3Specifications
All output specifications are measured into a 50 pF load connected with 6 ft (~1.8 m) of RG-62 (93 Ω) coaxial cable, at 1,500 V output. The PVX-4150 can drive loads from a few picofarads to several hundred picofarads, limited by its maximum power dissipation. It can also drive resistive or inductive loads within limits; contact Berkeley Nucleonics for application assistance.
| Output | Specification |
|---|---|
| Maximum value | ±1,500 V (VHigh − VLow) |
| Minimum value | 0 V |
| Means of adjustment | Controlled by power supply input voltages |
| Pulse rise and fall time | <25 ns, typically <20 ns (10% to 90%); ~18 ns at 1,500 V |
| Pulse width | <60 ns to DC, controlled by input gate |
| Pulse recurrence frequency (PRF) | Single-shot to 240 kHz at 1,500 V continuous output (max. limited by power dissipation); 5 MHz burst, controlled by input gate |
| Max. average power | 150 W (VHigh + VLow), derated at 2 W/°C above 25 °C ambient |
| Max. duty cycle | Continuous |
| Droop | <1% |
| Over/undershoot | <5% |
| Throughput delay | 120 ns typical |
| Jitter | <1 ns shot-to-shot |
| Output connector & cable | SHV, with 6 ft (~1.8 m) RG-62 (93 Ω) coaxial cable |
| Input DC voltage | Specification |
|---|---|
| +VIN (VHigh) absolute max. | +1,500 V |
| +VIN (VHigh) absolute min. | −1,500 V |
| +VIN (VHigh) relative max. | +1,500 V over VLow voltage |
| +VIN (VHigh) relative min. | +0 V over VLow voltage |
| −VIN (VLow) absolute max. | +1,500 V |
| −VIN (VLow) absolute min. | −1,500 V (only needed when biasing the output) |
| Input DC connectors | SHV, rear panel (one each for +VIN and −VIN) |
| Gate, monitors & general | Specification |
|---|---|
| Gate source & connector | TTL into 50 Ω, front-panel BNC |
| Voltage monitor | 1000:1 into 1 MΩ, BNC connector |
| Current monitor | 10 A/V into 50 Ω, BNC connector |
| Support power | 90–240 VAC, 50/60 Hz |
| Dimensions (H × W × D, excluding connectors) | 5.2 in × 19 in × 13 in (13.2 × 48.25 × 33 cm) |
| Weight | Approximately 18 lb (8.2 kg) |
4Front Panel & Monitoring
Front-panel indicator LEDs report the state of the pulse generator at a glance: output enabled, over-current, control error, gated, and power. Two monitor outputs sit on the front panel. The voltage monitor scales the output 1000:1 into 1 MΩ, and the current monitor reports 10 A per volt into 50 Ω. Together they let an engineer view the real-time output voltage and current waveforms on a standard oscilloscope, without a high voltage scope probe.
Power and enable controls are on the front panel. The over-current circuit shuts the output down on a fault from an arc or short, protecting both the pulser and the load. High voltage input and output connections are on the rear panel to keep the operator side of the instrument at low voltage.
5Remote & Gate Control
Pulse timing is driven entirely by the gate. The gate input accepts a TTL signal into 50 Ω on a front-panel BNC connector, and it sets both the pulse width and the repetition rate, including burst operation to 5 MHz. Output amplitude is set separately by the user-supplied high voltage DC supplies, so timing and amplitude are controlled independently.
Inverting the gate inverts the output, which is the standard way to produce a negative-going pulse from a normally-high baseline. For integration into automated or interlocked systems, contact Berkeley Nucleonics to confirm the available remote and status options for your configuration.
6Applications
- Time-of-flight mass spectrometry. High-rate pulsing of extraction grids and deflection plates for electrostatic modulation of ion beams.
- Accelerators and beam handling. Deflecting, gating, and kicking charged-particle beams.
- Electro-optics. Driving Pockels cells and Q-switches in laser cavities where fast, low-jitter edges matter.
- Detector gating. Gating microchannel plates, photomultiplier tubes, and image intensifiers.
- Tube and transducer drive. Pulsing or gating power tube grids and acoustic transducers.
7Ordering Information
| Model | Description |
|---|---|
| PVX-4150 | ±1,500 V high voltage pulse generator, <25 ns rise/fall, <60 ns to DC pulse width, single-shot to 240 kHz with 5 MHz burst, with voltage and current monitors |
The PVX-4150 requires a user-supplied high voltage DC source and a TTL gate. A second DC supply is needed only when the output is biased away from ground. Berkeley Nucleonics can advise on supply sizing from the load capacitance, pulse voltage, and repetition rate.
Contact
For a quote, configuration help, or application support, reach the Berkeley Nucleonics team.
Email: info@berkeleynucleonics.com
Phone: 800-234-7858