MC33099CDW FREESCALE [Freescale Semiconductor, Inc], MC33099CDW Datasheet - Page 8

• Manufacturer Part Number: MC33099CDW
• Description: Adaptive Alternator Voltage Regulator
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

automotive system voltage using diode-rectified alternator
charging systems commonly found in automotive
applications. The 33099 provides either an analog or digital
duty cycle control of an ON/OFF ratio of an alternator field
current at a fixed frequency. This provides for a Load
Response Control (LRC) of the alternator field current at low
engine RPM to eliminate engine speed hunting and vibration
owing to abrupt torque loading of the engine when a sudden
electrical load is applied to the system. Four LRC rates are
selectable using a combination of pins 7 and 8 being
connected to ground.
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33099
FUNCTIONAL DESCRIPTION
INTRODUCTION
The 33099 is specifically designed for regulation of an
FUNCTIONAL DESCRIPTION
INTRODUCTION
to activate the alternator field current in response to system
load current. The output voltage is monitored by an internal
voltage divider scheme and compared to an internal voltage
ramp referenced to a bandgap voltage. The 33099 regulates
the system voltage to 14.8 V for the DW suffix and to 14.6 V
for the CDW suffix by generating a pulse width modulation
(PWM) voltage waveform at the GATE of an external
MOSFET to provide an average alternator field coil current as
a function of the internal voltage comparison.
The 33099 provides a regulated voltage feedback system
Analog Integrated Circuit Device Data
Freescale Semiconductor