VG497 FMSH 3.5–28V Analog IC DIP16

The FMSH VG497 is an analog ic. The FM497 is an integrated electronic ignition controller for breakerless ignition systems using Hall effect sensors. The device drives an NPN external darlington to control the coil current providing the required stored energy with low dissipation. This circuit has many advantages: low power dissipation, stable, high ignition energy, self-protection, widely application conditions, long using life, etc. It’s compatible for overseas products of the same class.

Key Specifications

Features

• ‹ Direct driving of the external power darlingto
• ‹ Coil current charging angle (dwell) contro
• ‹ Programme coil current peak limitatio
• ‹ Programmable dwell recovery time when 94% nominal current not reached ‹ RPM output
• ‹ Permanent Conduction protectio
• ‹ Overvoltage protection for external darlingto
• ‹ Internal supply zener
• ‹ Reverse battery protectio Pin Functions Pi Functio Pi Functio GND Max Condition Time Signal GND Dwell Contro Power Supply Dwell Contro N.C Bias Current Hall Effect Input Current Sensing RPM Output Driver Emitter Output AUX Zener Overvoltage Limit Recovery Time

Design Notes

• The trip threshold is specified over a tolerance band, not at a single point. Design the sense resistor against the worst-case ends of that band, or nuisance tripping will appear at temperature extremes.
• These circuits are usually supplied from a capacitive dropper or a resistive divider off the mains. Verify the supply current budget against the datasheet before adding load.
• Package choice drives creepage. For mains-referenced parts, use the widest package the layout allows and keep the specified clearance to the low-voltage side.
• Check the temperature coefficient of the threshold if the product must hold accuracy over an outdoor temperature range.

Common Questions

What is the trip threshold?

the threshold above. The threshold is specified over a tolerance band, so size the sense element against the band ends rather than the typical value.

What does this device do?

Hall-Effect automobile ignition controller. It integrates the control loop that would otherwise need a board of discrete parts.

Which packages are offered?

DIP16. For mains-referenced circuits choose the package that meets the creepage requirement of the layout.

How is it powered?

Typically from a capacitive dropper or resistive divider off the mains rail. Check the supply current budget in the datasheet before adding any load to that rail.