Menu

Vigitek

  • 203.829.5756
  • [javascript protected email address]
Home Electro-optics Avalanche Transistor-based Pockels Cell Drivers Q-switch Driver PCDA4-01

Q-switch Driver PCDA4-01

Generation of quasi-rectangular High Voltage Pulses for the control of Electro-Optical Q-switches (Pockels Cells) in a Solid-State Laser.

Distinctive Feature

  • Positive High-Voltage Pulse – «Switch-on» Operational mode;
  • Low-voltage DC supply required (5 ÷ 12V);
  • Built-in, pulsed HV-Source;
  • Adjustment of a high-voltage pulse either directly on the board (through built-in potentiometer) or remotely;
  • TTL input signal required (5-12V);
  • Highly reliable topology;
  • Ultra-compact size – can be used for actively Q-switched, hand-held Q-switched laser heads.
  • Low-Jitter.

Technical Specifications

Technical Specifications

    • High-Voltage Amplitude1……………………………………………………………….. 2800 ÷ 3800 V
    • HV Pulse-to-Pulse Instability…………………………………………………………………………….. 5 %
    • Max Current During Pulse………………………………………………………………………………….. 40 A
    • Max Capacitance…………………………………………………………………………………………………….. 50 pF
    • Rising Front Duration2 ………………………………………………………………………………………..  2 ÷ 4 nsec
    • HV Pulsewidth (factory-set)3 ……………………………………………………………………………  0.5 ÷ 2 μsec
    • Falling Front Duration…………………………………………………………………………………………. 2 ÷ 4 μsec
    • Max Repetition Rate (Frequency)
      • With 4.6 mm transformer…………………………………………………………………………….. 2 kHz
      • With 9.2 mm transformer…………………………………………………………………………….. 5 kHz
    • Input TTL Signal Amplitude………………………………………………………………………………. 3 ÷ 12 V
    • HV Pulse delay Vs. TTL trigger pulse4……………………………………………………………. 20 ÷ 30 nsec
    • Timing Jitter of the HV Pulse Vs. Trigger……………………………………………………… < 900 psec
    • Input TTL Signal Amplitude………………………………………………………………………………. 5 ÷ 12 V
    • Current:
      • 5V/2kHz ………………………………………………………………………………………………………………  250 mA
      • 12V/5kHz ……………………………………………………………………………………………………………  250 mA
    • Working Temperature Range…………………………………………………………………………… –40 ÷ +60 °C
    • Dimensions ………………………………………………………………………………………………………………  30 × 50 × 8 mm3
    • Mounting Hole Pattern (Æ 3.2 mm) ……………………………………………………………….  24 × 44 mm

1 Is set from the built-in potentiometer or remotely.
2 Depends on the load inductance and HV amplitude.
3 Set during fabrication.
4   Delay depends on the TTL pulse. The higher trigger amplitude, the shorter delay.

Pockels Cell Driver – 01 Connection Diagram

Connector J1 (input):
Pin 1 (brown)     – power supply + (5 ÷ 12) V & 250 mA;
Pin 2 (red)          – power supply GND;
Pin 3 (orange)    – trigger input + (3 ÷ 12) V & 25 mA; rising edge < 50 nsec; duration > 50 nsec;
Pin 4 (yellow)     – trigger GND;
Pin 5 (green)      – output voltage measure signal; DC voltage scale 1:10000;
Pin 6 (cyan)        – output voltage measure GND.

Connector J2 (output):
Pin 1 (HV black) – negative high voltage output signal;
Pin 2 (HV black) – GND.

Note 1. Pin 5 and 6 can be used for setting the amplitude of the output voltage pulse; for instance:

V(out) = 3860 – V(pin5) × 1570 [V] ;  or  V(pin5) = 2.46 – 0.000637 × V(out)  [V] .

For this purpose, using trimmer R46 set the amplitude of the output pulse voltage to 3340 V without connecting the control voltage V(pin5), or 3860V at control voltage V(pin5) is 0V.

The input impedance of the pin 5 is 2.87 kΩ.

Indirect (non-touching) monitoring of the output pulse waveform.

Oscilloscope probe (1:10) must be placed in close proximity to the HV connector (or resistors R13 and R14), but without actually touching it. The scale of the oscilloscope must be set on the 2 ÷ 10 V/D.

Below are the photos of direct oscilloscope measurements of the output HV – please note that all measurements must be carried out only with respect to the GND.