QBD-BT-series consists of several Pockels cell drivers that differ with output voltage range (up to 6.0 kV bipolar) and operating scheme (see also How to order? section). Please, note that by bipolar device an output pulse voltage U is formed by applying +U/2 to positive output wire and –U/2 to negative.
QBD-BT-series is specially designed to control Pockels cells by applying a fast switching high voltage. The voltage level and operating frequency can be selected in working range by user through RS-232 or through the front panel. Triggering is carried out automatically or via a signal from an external device.
Devices are encased and easy for the user to mount, they run on common 100-240 V AC 50/60 Hz, so, you don't need extra power supply for the driver.
There are two possible modifications of output signal type:
- push-up (= normally off scheme), when a base voltage level equals to zero
- pull-down (= normally on scheme), when pulses from base bias voltage to ground are generated.
The desired one should be chosen at the time of ordering and could not be changed by the user.
QBD-BT-series is based on MOSFET technology and offers high repetition rates and fast transition time for a leading pulse edge. The recovery time by QBD-BT is relatively long (5-10 μs for the trailing pulse edge vs < 20 ns by QBU-BT).
Performance
In internal synchronization mode the QBD-BT-series (from QBD-BT-1004-UP/DN to QBD-BT-6024-UP/DN) performance is limited to values given in a table below. The total capacitive load of Pockels cell and connective cable is assumed to be 23 pF (this corresponds to 50 cm output cable bent in non-optimal way and higher than normal Pockels cell capacitance).
Even higher performance can be achieved in external synchronization mode and/or in burst mode (i.e. for short term operations).
The performance deteriorates for higher load capacitance.
Output:
Modifications by working modes
pull-down (= normally on)
or push-up (= normally off)
Synchronization
internal and external
Voltage, high level
regulated, up to 6 kV
1
Voltage, low level
fixed, 0 V
Maximal repetition rate
up to 100 kHz and higher (load and voltage dependant, see also Performance section)
1
Rise time (fall time)
< 20 ns
2
Recovery time
5-10 us (depends on load)
Load capacitance
up to 0.5 nF
1
Environment:
Operation temperature
0 … +40 °C
Storage temperature
-20 … +60 °C
Humidity
0 ... 90%, non-condensing
Other:
Size (LxWxH)
225x200x60 mm
1)
these parameters aren't indepenent and cannot achieve their maximum at the same time
2)
10-90% level, guaranteed at load capacitance 23 pF and below
Pull-down (normally on) modifications
Pull-down scheme,
2.4-6.0 kV high voltage adjustment range
Pull-down scheme,
2.0-5.0 kV high voltage adjustment range
Pull-down scheme,
1.6-4.0 kV high voltage adjustment range
Pull-down scheme,
1.2-3.0 kV high voltage adjustment range
Pull-down scheme,
0.8-2.0 kV high voltage adjustment range
Pull-down scheme,
0.4-1.0 kV high voltage adjustment range
(*) Other output voltages are available on request
Push-up (normally off) modifications
Push-up scheme,
2.4-6.0 kV high voltage adjustment range
Push-up scheme,
2.0-5.0 kV high voltage adjustment range
Push-up scheme,
1.6-4.0 kV high voltage adjustment range
Push-up scheme,
1.2-3.0 kV high voltage adjustment range
Push-up scheme,
0.8-2.0 kV high voltage adjustment range
Push-up scheme,
0.4-1.0 kV high voltage adjustment range
(*) Other output voltages are available on request
Example
Pull-down scheme,
2.0-5.0 kV high voltage adjustment range
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