MOTOROLA

SEMICONDUCTOR TECHNICAL DATA

© Motorola, Inc. 2004

Document order number: MC33099

Rev 4.0, 07/2004

33099

Simplified Application Diagram

33099

FIELD

WINDING

IGNITION

SWITCH

CHASSIS

PHASE

GATE

SOURCE

PHASE FILTER

BAT

IGN

LAMP DRAIN

AGND

LRC1

LRC2

REMOTE

GND

Adaptive Alternator Voltage

Regulator

The 33099 is designed to regulate the output voltage in diode-rectified

alternator charging systems common to automotive applications. The 33099

provides either an analog or digital fixed frequency duty cycle (ON/OFF ratio)

control of an alternator’s field current. Load Response Control (LRC) of the

alternator field current is accomplished by selecting the duty cycle for

prevailing engine conditions to eliminate engine speed hunting and vibrations

caused by abrupt torque loading of the engine owing to sudden electrical loads

being applied to the system at low engine RPM. Four LRC rates are

selectable.

The 33099 uses a feedback voltage to establish an alternator field current

that is in harmony with system load currents. The output voltage is monitored

by an internal voltage divider scheme and compared to an internal voltage

ramp referenced to a bandgap voltage. This approach provides precision

output voltage control over a wide range of temperature, electrical loads, and

engine RPM.

Features

• External High-Side MOSFET Control of a Ground-Referenced Field

Winding

• LRC Active During Initial Start

• <0.1 V Variation Over Engine Speeds of 2,000 to 10,000 RPM

• <0.2 V Variation Over 10% to 95% of Maximum Field Current

• Controlled MOSFET and Field Flyback Diode Recovery Characteristics

for Minimum RFI

ALTERNATOR VOLTAGE

REGULATOR

ORDERING INFORMATION

Device

Temperature

Package

MC33099DW/R2

-40°C to 125°C

16 SOICW

MC33099CDW/R2

DW SUFFIX

CASE 751G-04

16-TERMINAL SOICW

33099 Simplified Application Diagram

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com