ChipFind - документация

Электронный компонент: U6432B-FP

Скачать:  PDF   ZIP
1
4725AAUTO06/03
Features
Temperature and Voltage Compensated Frequency
Warning Indication of Lamp Failure by Means of Frequency Doubling only in Direction
Mode
Voltage Dependence of the Car Indicator Lamps also Compensated for Lamp Failure
Relay Output with High Current-carrying Capacity and Low Saturation Voltage
Load-dump Protection
Minimum Lamp Load for Flasher Operation
1 W
Low Susceptibility to EMI
Extremely Low Standby Current of 10 A
Protection According to ISO/TR 7637/1 Level 4 with External Capacitor (C
2
)
Description
The U6432B is an advanced automotive flasher IC which provides low standby cur-
rent. Its basic function is equal to Atmel's flasher IC U6043B but low current
consumption and frequency doubling disabling make outstanding differences.
Low-power
Flasher IC with
18-m
W
Shunt
U6432B
2
U6432B
4725AAUTO06/03
Block Diagram
Figure 1. Car Flasher Application
V
S
-57 mV
V
S
-57 mV
G
4
G
2
G
1
+
-
+
-
+
-
K
1
K
3
K
2
G
5
G
3
T
1
D
2
6.2 V
D
1
2
V
S
8
1
7
3
21 V
V
S
-6 V
6
4
5
4.7 F
R
1
V
S
82 k
W
V
S
49 a
10 F
1.2 k
W
R
2
Shunt
R
3
18 m
W
R
4
5.1 k
W
470
W
R
6
P
L
>1 W
T
2
C
1
C
2
3
U6432B
4725AAUTO06/03
Pin Configuration
Figure 2. Pinning
SI
LD
OSC
GND
VS
OSC
REL
1
2
3
4
8
7
6
5
U6432B
VS
Pin Description
Pin
Symbol
Function
1
GND
IC ground
2
VS
Supply voltage
3
REL
Relay driver
4
OSC
Oscillator
5
OSC
Oscillator
6
VS
Supply voltage
7
LD
Lamp failure detection
8
SI
Start input (49a)
4
U6432B
4725AAUTO06/03
Functional Description
Pin 1, GND
The U6432B is protected against damage in case of battery reversal via resistor R
4
to
ground (-31). An integrated protection circuit together with external resistances R
2
and
R
4
limits the current pulses in the IC.
Pin 2, Supply Voltage,
V
S
power
The arrangement of the supply connections to Pin 2 (and 6) must be so as to ensure
that on the connection printed circuit board (PCB), the resistance of V
S
to Pin 6 is lower
than that to Pin 2.
Pin 3, Relay Control
Output (Driver)
The relay control output is a high-side driver with a low saturation voltage. It is capable
of driving a typical automotive relay with a minimum coil resistance of 60
W
.
Pin 4 and 5, Oscillator
The flashing frequency, f
1
, is determined by the R
1
C
1
components as given by the for-
mula below (see Figure 1):
where C
1
47 F, R
1
= 6.8 k
W
to 510 k
W
In case of a lamp outage (see Pin 7) the oscillator frequency is switched to the lamp out-
age frequency f
2
with f
2
2.2
f
1
.
Duty cycle in normal flashing mode: 50%
Duty cycle in lamp outage mode: 40% (bright phase)
Pin 6, Supply Voltage,
Sense
For accurate monitoring via the shunt resistor, a minimized layer resistance from point
V
S
/shunt to Pin 6 is recommended.
Pin 7
Control Signal Threshold
(49 mV Comparator)
The detection point for lamp failure can be calculated from the control signal threshold,
typically 49 mV with V
S
= 12 V. With a measuring resistance of R
3
= 18 m
W
, the fre-
quency change-over is reached at a lamp load of 21 W + 11.4 W. The variation of the
control signal threshold supply voltage takes into account the PTC characteristic of fila-
ment lamps.
Control Signal Threshold 2
(15-mV Comparator)
A voltage drop at the shunt resistor R
3
between 49 mV and 15 mV lets the flasher work
in frequency doubling mode.
If the voltage drop decreases to a value below V
R3MAX
= 15 mV, frequency doubling is
disabled.
This can be achieved either with a switch which by-passes the shunt resistor (e.g., a
special hazard warning switch) or with a small lamp load.
Flasher operation starts with a lamp load of P
L
1 W.
f
1
1
R
1
C
1
1.5
-----------------------------------
Hz
5
U6432B
4725AAUTO06/03
Pin 8, Start Input
Start condition for flashing:
Voltage at Pin 8 (see Figure 1)
V
8
V
S
- (V
BE(T1)
+ V
Z(D2)
)
Condition for standby:
The resistor R
2
betwen V
S
and Pin 8 provides an extremly low standby current
(I
S
10 A). The leakage current depends on the pull-up resistor R
2
according to
the following formula:
I
Leak
(V
BE(T1)
+ V
Z(D2)
)/R
2
Application Hint
In order to achieve a high-level immunity against "electrical interference by conduction
and coupling" according to ISO/TR 7637/1 test level 4, an electrolythic capacitor
C
2
= 10 F (25 V) between Pin 1 and 2 mounted close to the IC is highly
recommended.
Absolute Maximum Ratings
Reference point Pin 1
Parameters
Symbol
Value
Unit
Supply voltage
Pin 2 and 6
V
S
18
V
Surge Forward Current
t
P
= 0.1 ms
t
P
= 300 ms
t
P
= 300 ms
Pin 2 and 6
Pin 2 and 6
Pin 8
I
FSM
I
FSM
I
FSM
1.5
1.0
30
A
A
mA
Output current
Pin 3
I
O
0.3
A
Power Dissipation
T
amb
= 95
C
T
amb
= 60
C
DIP 8
SO8
DIP 8
SO8
P
tot
P
tot
P
tot
P
tot
420
340
690
560
mW
mW
mW
mW
Junction temperature
T
J
150
C
Ambient temperature range
T
amb
-40 to +105
C
Storage temperature range
T
stg
-55 to +150
C