AN874 Datasheet, PDF (3/3 Pages) Maxim Integrated Products – Using the MAX6950 and the MAX6951 LED Display Drivers with Multiplex Dual-Digit Displays

APPLICATION NOTE
The corresponding energy can be calculated by :
∫^tFR
W ON = v. i dt
o
by using this formula and the switching oscillogram
of the DTV64D we find :
WON = 11.3µ J
Switching ON losses are given by :
PON = Won x F
Example : With a DTV64D
Ip = 6A
dIF/dt = 60A/µs
Tj = 100°C
F = 64kHz
We have
and
WON = 11.3µ J
PON = 0.73W
Total losses in the damper diode : PT
The reverse losses due to the leakage current are
negligible and the switching OFF losses with ST
damper diodes are also negligible.
So total losses in the damper diodes are the sum of
the conduction losses and the switching ON
losses :
PT = PON + Pcond
Example : DTV64D
Ip = 6A
δ = 0.45
F = 64kHZ
PT = 2.1W
CONCLUSION
The new damper diodes have been optimized for
horizontal deflection circuits working at high
frequencies. A new technology has been
developed to reduce the peak forward voltage as
much as possible. The compromise between trr
and VF has been chosen to be sure that switching
OFF losses are negligible. SGS THOMSON offers
high frequencies damper diodes DTV64D,
DTV82D, DTV110D for operation typically at 64,
82 and 110kHz. Obviously each diode can be used
for higher frequencies : for example a DTV82D can
be used at 110kHz, in this case the total losses will
be higher than with a DTV110D.
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsability for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express
written approval of SGS-THOMSON Microelectronics.
© 1996 SGS-THOMSON Microelectronics - Printed in Italy - All rights reserved.
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