Adaptive Alternator Voltage Regulator

The 33099 is designed to regulate the output voltage in dioderectified 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 by connecting pins 7 and 8 to ground.

Features

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

• LRC Active During Initial Start

• Vset at ±0.1 V @ 25°C

• <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

• Trimmed Devices Available at 14.6 V and 14.8 V (typical) Vset

• Pb-Free Packaging Designated by Suffix Code EG