Q-switch Driver «PCD-02» with differential output
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Q-switch Driver «PCD-02» with differential output
gnatyuk@mail.ru February 2013

Application

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

Distinctive Features

✓   High-Voltage Pulse is formed by a symmetrical, bi-polar output in «Switch-on» Operational mode;
✓ Low-voltage DC supply required (5 ÷ 7 V);
✓ Built-in, pulsed HV-Source;
✓ Adjustment of a high-voltage pulse either directly on the board (through built-in potentiometer) or remotely;
✓ Significantly reduced electro-magnetic noise;
✓ TTL input signal required (3 ÷ 12 V);
✓ Highly reliable topology;
✓ Ultra-compact size – designed for handheld Q-switched laser heads.
Technical Specifications
  • High-Voltage Amplitude 1
    		•  2800 ÷ 3800 V
  • HV Pulse-to-Pulse Instability
    		•  5 %
  • Max Current During Pulse
    		•  40 A
  • Max Capacitance
    		•  50 pF
  • Rising Front Duration 2
    		•  1 ÷ 2 ns
  • HV Pulsewidth (factory-set) 3
    		•  0.5 ÷ 2 µs
  • Falling Front Duration
    		•  1 ÷ 2 µs
  • 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 pulse 4
    		•  15 ÷ 30 ns
  • Timing Jitter of the HV Pulse Vs. Trigger
    		•  < 1 ns
  • DC Voltage to power the driver
    		•  4.5 ÷ 7.5 V
  • Current
    		•
    At a repetition rate of 2 kHz 250 mA
    At a repetition rate of 5 kHz 400 mA
  • Working Temperature Range
    		•  –40 ÷ +60 °C
  • Dimensions (with 4.6 mm transformer)
    		•  30 × 50 × 8 mm³
  • Mounting Hole Pattern (∅ 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.
    Connection Diagram
    Connector J1 (input):
    Pin 1 (brown) – power supply + 5 V & 250 mA;
    Pin 2 (red) – power supply GND;
    Pin 3 (orange) – trigger input + (3 ÷ 8) V & 25 mA; rising edge < 50 ns; duration > 50 ns;
    Pin 4 (yellow) – trigger GND;
    Pin 5 (green) – output voltage measure signal; DC voltage scale 1:10000; NOTE 1
    Pin 6 (blue) – output voltage measure GND.

    Connector J2 (output):
    Pin 1 (HV blue) – negative high voltage output;
    Pin 2 (HV red) – positive high voltage output.

    Note 1. Pin 5 and 6 can be used for setting the amplitude of the output voltage pulse:
    V(out) = 3860 – V(pin5) × 1570 [V] ; or V(pin5) = 2.46 – 0.000637 × V(out) [V] .
    For this purpose, with a trimmer R46 to set the amplitude of the output pulse voltage 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 3.2 kOhms.
    Output Waveform
    The transmission of the Pockels cell with the driver PCD-02

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