Mainz, Germany, August
05, 2005
Standard light sources such as bulbs are replaced by LEDs or LED
strings in more and more applications now. The ASIC manufacturer
PREMA Semiconductor offers the new constant current driver PR4130
controlling up to three LEDs in series. Even if one or two LEDs are
disconnected or short circuited, the current and the brightness
remain constant, thus providing a high reliability.
The supply voltage
of the PR4130 ranges from 10V up to 14.4V or a maximum voltage of
21V for short time. Necessary for operation is only one external
resistor, which defines the LED current in a range from 5mA up to
30mA.
Due to the very accurate current control the brightness of the LEDs
is very constant and almost independent of the supply voltage and
the number of connected LEDs.
The PR4130 circuit is compensating the disadvantage of serial LED
circuits, that a failure in one LED will lead to the disfunction of
the whole string. A Zener diode circuit provides a current flow also
with a break of one LED and together with the current control the
brightness of all connected LEDs stays smooth and constant also with
short circuit or break of one or two LEDs. The Zener diode circuit
has been defined for forward voltages of the LEDs of up to
2.3V.
Due to the supply voltage of around 12V the PR4130 is well suited
for automotive applications such as drivers for the third high
mounted stop light (Center High Mount Stop Light) consisting of a
string of more LEDs. In this case several PR4130 can be used in
parallel, uniformly distributed current is guaranteed by the current
control also at a failure of a single LED. Further applications are
decoration light strings with 12V power supplies.
The PR4130 is offered as a standard cell for design of an analog
ASIC. Production of a custom specific standard cell IC can be
reasonable for annual amounts from several 10 k units. The NRE cost
are comparatively low and adaptions, eventually necessary, will in
most cases be implemented easily. Further information and a
datasheet of the PR4130 are available on the web site www.prema.com/Application/pr4130_e.html.
General information about PREMA Semiconductor GmbH, Mainz
PREMA offers solutions for analog and mixed-signal ASICs
- with supply voltages from 0.9V up to 120V
- for the ultra low power range up to medium power
- development, design, production and test, all in one hand.
ASICs from PREMA can be found
- in low noise audio electronics
- in battery management of household devices
- in mobile phones and moving sensors
- in bar code readers and sensors (light and magnetic field)
We cordially invite you to visit our website: www.prema.com
to find more information about us and our services.
Contact:
Anne Stroot, PREMA Semiconductor GmbH
Phone: +49-6131-5062-202
prema@prema.com
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