L585 Datasheet, PDF (5/9 Pages) STMicroelectronics – CAR ALTERNATOR REGULATOR

L585
ELECTRICAL CHARACTERISTICS (continued)
Symbol
Parameter
Test Conditions
Min. Typ. Max. Unit
PROTECTION
T_sh
Darlingtyon Thermal Shutdown
Threshold
150
°C
VZen
V1dp
I_{1 3 sc}
Idump
VZ13
(pin 10) Zener Voltage
IO = 60mA
I_O = 130mA
Overvoltage Protection
Threshold (7)
T_j = 25°C
– 30°C < Tj < + 100°C
Lamp Driver Circuit Current
Pin 13 Dump Sustaining Capapility V1 3 = 110V@ T_j = 25°C
Current
V₁ = 50V@ t = 100ms
Zener Clamping Voltage
I1 3 = 100mA@
t = < 3ms
6
8
V
6.2
8.2
V
25
32
38
V
23
40
V
300
1500 mA
200
mA
110
V
I1 3 = 40mA@
100
V
t = < 6ms, full T
T_J = -30°C
90
V
Notes : 1. d = 50 % the duty cycle of the output signal at pin 6.
2. The lamp is switched on with a fixed delay when the alternator voltage becomes higher than VAH. (overcharge indication).
3. Measured 100 ms after turn-on.
4. The lamp is switched on with a fixed delay when the voltage Vp becomes lower than VPL (the alternator is not charging the battery).
5. The lamp is switched on when the cable B is broken (VA - VS becomes higher than VAS).
6. The lamp is switched on when the cable A is broken (IC without power voltage supply).
7. When the voltage at pin 1 is greater than V1 dp the internal darlington of the lamp is switched off.
CIRCUIT OPERATION
The L585 alternator regulator performs two main functions : regulation control and fault diagnostics.
REGULATION
The alternator voltage is compared with a reference
voltagein an error amplifier (see block diagram), the
output of which determines the duty cycle of the ex-
ternal darlington. This darlington switches the cur-
rent in the excitation coil of the alternator.
The switching frequencyis fixed and is set by the ex-
ternal capacitor C_OSC (see application circuit). Ca-
pacitive positive feedback and a monostable elimi-
natesspurious switching caused by contact bounce.
The basecurrent deliveredto the external darlington
it set by the resistor RB (see application circuit) and
must be dimensioned according to the charac-
teristics of this darlington and the maximum coil cur-
rent.
DI AG NO ST I C
This circuit receives informationfrom the battery,the
alternator and one alternator phase. It indicates
anomolousconditions by driving a 3 W lamp. To pre-
vent spurious fault warnings some indications are
not displayed immediately but are delayed by a fixed
time. No external components are needed to imple-
ment this delay since it is produced internally by di-
viding the internal oscillator with an eight-stage di-
vider to give a delay of 128 periods. For a one sec-
ond delay the oscillator frequency must be 128 Hz.
The lamp is driven after a delay when the following
conditions occur : no charge, break or short circuit
in the alternator sense wire.
The diagnostic lamp is driven immediately when the
cable connectingthe alternator to the battery is bro-
ken (Va-Vbatt above 2.6 typ.) or when the IC is with-
out power supply (V_{CE sat} of the lamp driver is 2.4 V
typ. in this case).
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