L9407F(2008) 查看數據表（PDF） - STMicroelectronics

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比赛名单

L9407F
(Rev.:2008)

Preliminary Data Car alternator voltage regulator

STMicroelectronics 

L9407F

1

Functional description

Functional description

1.1

Circuit operation

The alternator's voltage regulator performs the following main functions:

● voltage regulation

● protection

● control fault diagnosis

● load response control

) 1.2

Voltage regulation

t(s The alternator voltage is compared with a reference voltage in an amplifier, whose output

c determines the switching frequency of output power MOS whose current excites the coil of

du the alternator; as the regulators are a self-oscillating type this frequency depends on the

ro whole system parameter set including the alternator characteristics. The regulators have an

integrated filter in the voltage sensing path guaranteeing the correct behavior of the devices

P also when the rectifier diodes feature very high switching spikes. The internal filtering allows

te the usage of the device also with very long cables connecting the alternator to the battery

le with an impedance so high to cause a superimposed ripple on the alternator voltage higher

o than 5-6V. Consequently it doesn't need, in the standard application, any external

s component. Anyway an external application (2.2µF or 2.7µF) must be inserted between A+

b and ground when using the device with very long cables.

t(s) - O 1.3

Protection

c It is present a protection against short circuits of the lamp and the relay power drivers (D+)

u and of the field power driver (DF), a thermal drivers shutdown protection and an overvoltage

rod protection of D+ power drivers.

te P 1.4

Diagnosis

oleThe circuit detects fault conditions related to the phase and DF status and receives

s informations from one of the three alternator phases. In order to prevent spurious

Ob indications, fault warnings are not displayed immediately but are delayed by a fixed time.

1.5

Load response control

The internal circuit regulates the soft start characteristics (activated always at engine start)

and the soft attack characteristics.

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