Q-switch Driver PCDA4-02

• High-Voltage Amplitude ¹………………………………………………………………………………… 2800 ÷ 3800 V
• HV Pulse-to-Pulse Instability…………………………………………………………………………….. 5 %
• Max Current During Pulse…………………………………………………………………………………. 40 A
• Max Capacitance……………………………………………………………………………………………….. 40pF
• Rising Front Duration ² …………………………………………………………………………………….  1 ÷ 2 nsec
• HV Pulsewidth (factory-set) ³ …………………………………………………………………………..  0.5 ÷ 2 μsec
• Falling Front Duration………………………………………………………………………………………  1 ÷ 2 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 pulse ⁴……………………………………………………………..  15 ÷ 30 nsec
• Timing Jitter of the HV Pulse Vs. Trigger………………………………………………………….  < 900 psec
• DC Voltage to power the driver…………………………………………………………………………  4.5 ÷ 7.5 V
• Current
  • 2kHz …………………………………………………………………………………………………………. 250 mA
  • 5kHz …………………………………………………………………………………………………………  400 mA
• Working Temperature Range……………………………………………………………………………. –40 ÷ +60°C
• Dimensions ……………………………………………………………………………………………………..  30 × 50 × 8 mm³
• Mounting Hole Pattern (Ø 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 PCDA4-02 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;
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. 

Pins 5 and 6 can be used for the remote adjustment of the HV pulse’ amplitude relative to the value set by potentiometer RV46 within a range of +2% to -20%.

That is, if a voltage of U=0V is applied from the external source to pin 5. – then HV amplitude would be ~2% higher than nominal setting.

If U=5V is applied to pin 5, then amplitude would be lower by ~20%. The input impe- dance of the pin 5 is ~26kΩ.

To correctly operate driver PCDA4-02, it must be triggered by the electric pulse with following
parameters:

• The amplitude of the trigger-pulse (on pin 3 of connector J1) must be higher than 3V, and
  preferably 5V (permitted up to 12V).
• Rise time of the trigger-pulse (on pin 3 of connector J1) must be shorter than 50 nsec.
• Need to provide the input current (on pin 3 of connector J1) higher than 25 mA. This will require a powerful and fast signal generator.

Electric Block-Diagram of «Pockels Cell Driver – PCDA4-02»

• If an isolated trigger pulse is required, it’s necessary to use opto-couple with logic output, for example HCPL-2611 or OPI1268. Digital isolators type Si8710 or Si8610 can also be used.

Output waveform of the Pockels Cell Driver – 02

Low-voltage indirect (non-touching) monitoring of the output pulse waveform:

Oscilloscope probe (1:10) must be placed in close proximity to the pin 1 of the HV connector J2 (or resistors R14), in the next place to the pin 2 of the HV connector J2 (or resistors R13), but without actually touching it. The scale of the oscilloscope must be set on the 1 ÷ 10 V/D.

High-voltage low-frequency measurement of the output voltage:

Measurements can be made simultaneously by the two probes.
Output voltage – the sum of two measurements.

High-voltage high-frequency measurement of the output voltage:

Measurements can be made simultaneously by the two probes.
Output voltage – the sum of two measurements.