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PRODUCT SELECTION:
High voltage and pulsed power applications
imply always a certain risk of sparking and flash over by nature,
especially if the ambient conditions, operating conditions, or load
conditions change unexpectedly. Therefore, the peak current capability
of a solid-state switch should be always as high as possible, at the
very least higher than the possible short circuit current of the
application. Regarding the selection of voltage rating we suggest a
safety margin of at least 5 % for MOSFET switches and at least 20 %
for all bipolar switches (IGBT, MCT, SCR) to minimize the risk of
damage by unexpected voltage fluctuation or unexpected
flyback-voltage. The long-term reliabillty, respectively, the Mean
Time Between Failures (MTBF) of a high voltage solid-state switch is
always a function of its operating temperature. Therefore, we highly
recommend operating the switches only at moderate temperatures
whenever possible. This is achieved primarily by choosing sufficient
on-resistance, current capability, natural capacitance and coupling
capacitance. Please refer to our
General Instructions
for the resistive and capacitive
power loss calculations. In cases that the calculated power
dissipation exceeds the Pd(max)
rating of the switch, appropriate cooling options must be added.
Please note, that the individual Pd(max)
ratings are always referred
to a housing temperature of 25°C. This laboratory test condition is of
course not given in practice. Designers must also consider increased
ambient temperatures as well as the actual housing temperature in
operation. Therefore, many applications require special cooling
measures. BEHLKE offers a broad selection of cooling options for every
situation. Designers can choose between ceramic cooling surfaces,
cooling fins, cooling flanges and liquid cooling with water or
dielectric coolants. Please refer to the data sheets and the following
product surveys for further information. |
TECHNICAL SUPPORT:
In
order to exclude any technical misunderstanding and to work
efficiently to the benefit of our customers, we do not provide any
oral consultation or technical support on the phone, except for
unavoidable urgent cases. For a first time consultation, please
carefully fill in our
questionnaire
or describe your application as precisely
as possible on a separate sheet and send it to BEHLKE by
email
or fax. We assure you, that all your technical information will be
handled strictly confidential. Submitted Non Disclosure Agreements
(NDA) will be legally verified and signed within one working day. Any
qualified aftersale support requires a complete set of information
about your application. This includes a drawn or sketched circuit
diagram, timing diagram, measuring values and oscilloscope screen
shots, as well as reliable information about the actual operating
conditions (voltage, current, frequency, pulse width, duty cycle,
transition times, operating temperature etc.). Additional pictures of
the experimental set-up can help to analyze and troubleshoot your
application more efficiently and faster. Due to high capacity
utilization of our support & development department, the processing of
technical inquiries may take from one day up to several weeks,
depending on the complexity of the application, the availability of
the individual experts and the quality and completeness of the
technical information provided by the customer.
Please also note that BEHLKE is a true
part components manufacturer. We provide free support for our products
but we do not develop applications unless we are explicitly ordered.
We also do not overtake any responsibility or warranty for the
function of our products in customer applications. Thank you for your
understanding. |
