MC33099DWSLASHR2 datasheet(9/20 Pages) MOTOROLA

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MOTOROLA ANALOG INTEGRATED CIRCUIT DEVICE DATA

33099

APPLICATIONS

Introduction

The 33099 is an alternator voltage regulator designed with

internal level shifting resistors to control the voltage in a 12 V

automotive system that uses a three-phase alternator with a

rotating field winding. The system shown in Figure 2 includes

an alternator with its associated field coil, stator coils and

rectifiers, an automotive battery, a fault indicator lamp, an

ignition switch, a field flyback diode, and the 33099.

Figure 2. 33099 Simplified Application

The 12 V system voltage (Vbat) is connected to a REMOTE

input by a remote wire, which provides the IC regulator with an

external Kelvin connection directly to the battery to provide

REMOTE voltage, Vrem. The system voltage at the BAT

terminal is also sensed by an internal Local IC connection as

Local voltage Vl. The Local connection is provided in the event

the remote wire or remote connection becomes faulty such as

being resistive, an open, or shorted to ground.

The PHASE input is normally connected to a tap on one

corner of the alternator's stator winding, which provides an AC

phase voltage (Vph) for the IC to determine the rotational

frequency (fph) of the alternator rotor. Two frequency

comparators (F1 and F2) monitor voltage Vph to determine a

phase rotation detection frequency (f1) and a Low/High RPM

transition phase frequency (f2), respectively. A PHASE FILTER

terminal is provided for externally providing a filter capacitance

for filtering phase input noise.

The regulated DC system set voltage (Vset) is achieved by

employing feedback to compare a ratioed value of Vset to an

internal IC bandgap voltage reference having a negative

temperature coefficient (TC). The GATE drive of an external

N-channel MOSFET is regulated by the IC to control the field

current in the alternator field coil as an alternating ON or OFF

state dependent on load current conditions affecting voltage

Vset. The external MOSFET receives GATE-to-source voltage

drive from between the GATE and SOURCE output terminals of

the IC. The GATE-to-source voltage is a Pulse Width

Modulated (PWM) waveform having a variable ON/OFF duty

cycle ratio that is determined by an analog or a digital duty cycle

control circuitry that responds to variations in the system

voltage due to variations in system load current. The PWM

Field

Ignition

500

Stator

Ground

Battery

Low

Pass

0.6 V

Over

Voltage

Detect

1.25 V

Bandgap

Reference

Regulator

VDD

Internal

V reg

and Bias

Current

Charge

Pump

Regulator

Min Duty

Cycle

OR1

Remote

Local

Sense

Phase

Batt

Gate

Vref

(5.0 V)

(2.0 V)

1.25 V

CB1

CB2

Css

VTssc

Ign

Delay

Gate

Polling

Local

4 LSB

4MSB

8-Bit Counter

Digital

Duty Cycle

Generator

U/D

Counter

Control

Switch

Up/Down

MUX

1.25 V

DAC

1.25V

Batt

Polling

Drain

Lamp

Driver

Circuit

OR2

LCR1

LRC2

AGnd

Gnd

Lamp

Drain

Lamp

Gate

IGN

Cds

Dtl

Logic

Polling

Lamp

u/d

A/D

Comparator

& Tracking

Limit

Current

Limit

Thermal

Batt

VTigm

Iign

VTdsc

(OTC)

Osc

Remote

Phase

Alternate S

tator

Configuration

LCR Test

P16

P 256

Source

Phase

Filter

Boundry for IC

MC33099

lpd

lpu

Vrem

Vrs

Vls

Cph

Crs

Vhvl

Vdac

Cdc

Cuv

Vfb

Cign

VBat

33099

REMOTE

PHASE

FILTER

PHASE

LCR TEST

LCR1 LCR2

GND

AGND

LAMP

GATE

LAMP

DRAIN

IGN

SOURCE

GATE

BAT

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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