L497 Datasheet, PDF (1/11 Pages) STMicroelectronics – HALL EFFECT PICKUP IGNITION CONTROLLER

L497
HALL EFFECT PICKUP IGNITION CONTROLLER
. DIRECT DRIVING OF THE EXTERNAL
POWER DARLINGTON
. COIL CURRENT CHARGING ANGLE (dwell)
CONTROL
. PROGRAMME COIL CURRENT PEAK LIMITA-
TION
. PROGRAMMABLE DWELL RECOVERY TIME
WHEN 94 % NOMINAL CURRENT NOT
REACHED
. RPM OUTPUT
. PERMANENT CONDUCTION PROTECTION
. OVERVOLTAGE PROTECTION FOR EXTER-
NAL DARLINGTON
. INTERNAL SUPPLY ZENER
. REVERSE BATTERY PROTECTION
DESCRIPTION
The L497is an integratedelectronicignition control-
ler for breakerless ignition systemsusing Hall effect
sensors.
DIP16
SO16
ORDERING NUMBERS : L497B (DIP16)
L497D1 (SO16)
The device drives an NPN external darlington to
control the coil current providingthe required stored
energy with low dissipation.
A special feature of the L497 is the programmable
time for the recovery of the correct dwell ratio Td/T
when the coil peak current fails to reach 94 % of the
nominal value. In this way only one spark may have
an energy less than 94 % of the nominal one during
fast acceleration or cold starts.
BLOCK DIAGRAM
March 1998
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