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Bosch Semiconductors for Automotive

CR291..294

Alternator regulator for 28V systems

Application & Technical Summary

CR260

CR291-294 regulates the output voltage of a 28 V alternator to a constant value.

The regulator continuously senses the alternator’s output voltage, rpm, temperature, excitation current. It adjusts the excitation current to keep the output voltage on a constant level.

Product benefits

  • Fully integrated alternator regulator
  • MFR Multi functional regulator

28.5V – 28.7V regulation voltage

variants for fixed regulation voltages available

Technical Features

Type
Voltage regulator for 28V alternators
Package
Bare Die
Functions to protect alternator and battery

  • Power stage shutdown at extreme temperature
  • Short circuit protection / recovery on DF power stage

Features

  • High-side DMOS regulated dynamo field (DF) by fixed
    frequency PWM
  • Integrated freewheeling diode on DF
  • DF duty cycle range up to 100 %
  • Active handling of over-voltage

Operating voltage
14 – 34 V
Extended operating voltage
8 – 54 V
Set voltage or B+
28.5 – 28.7 V
Setting
Fixed
Regulation
Analog
Freewheeling
Passive
Load response
No
High temperature shut-off
ESD handling
all pins: ±8 kV (HBM, 1.5 kOhm, 100 pF to GND)
Field protection
Yes
Regulation voltage
CR291 / 293: 28.5 V, CR292:
28.6 V, CR294: 28.7 V
Tj min [°C]
-40°C
Tj max [°C]
140°C

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