U6049B
TELEFUNKEN Semiconductors
Rev. A3, 04-Feb-97
1 (8)
Radiator Fan Controlled Timer
Description
The bipolar integrated circuit, U6049B, is designed as a
radiator fan controlled timer. After the ignition is
switched off, the thermal switch of the engine can activate
the radiator fan via relay for a preset period to support the
cooling process.
Features
D Delay time range: 3.7 s to 20 h
D Cooling time starts when thermal switch is closed
D RC-oscillator determines switching characteristics
D Relay driver with Z-diode
D Debounced input for coolant temperature switch
D Not debounced input for ignition key (Terminal 15)
D Load-dump protection
D RF interference protected
D Protection according to ISO/TR 7637-1 (VDE 0839)
Ordering Information
Extended Type Number
Package
Remarks
U6049B
DIP8
U6049BFP
SO8
Block Diagram
Stabilization
Power-on reset
Load-dump detection
Debouncing
Monoflop
Oscillator
Frequency divider
GND
94 8748
Relay con-
trol output
Logic
OSC
V
S
V
stab
6
7
8
R
2
C
2
R
1
C
1
510
W
V
Batt
1
2
Thermal switch
4
Programming
5
Ignition
3
V
Batt
2 k
W
R
5
R
4
C
3
100 nF
R
3
20 k
W
Terminal 15
Output
47
mF
Figure 1. Block diagram with external circuit
U6049B
TELEFUNKEN Semiconductors
Rev. A3, 04-Feb-97
2 (8)
Pin Configuration
Pin
Symbol
Function
1
GND
Reference point, ground
2
Output
Relay control output
3
Ignition
Signal input, ignition
4
S
th
Thermal switch, input
5
Program
Programming input
6
OSC
RC oscillator input
7
V
stab
Stabilized voltage
8
V
S
Supply voltage
1
2
3
4
8
7
6
5
GND
Output
Ignition
Program
OSC
V
stab
V
S
S
th
U6049B
13313
Figure 2. Pinning
Functional Description
Power Supply, Pin 8
For reasons of interference protection and surge immu-
nity, the supply voltage (Pin 8) must be provided with an
RC circuit as shown in figure 2a. Dropper resistor, R
1
,
limits the current in case of overvoltage, whereas C
1
smoothes the supply voltage at Pin 8.
Recommended values are: R
1
= 510
W, C
1
= 47
mF.
The integrated Z-diode (14 V) protects the supply volt-
age,V
S
. Therefore, the operation of the IC is possible
between 6 V and 16 V supplied by V
Batt
.
However it is possible to operate the integrated circuit
with a 5 V supply, but it should be free of interference
voltages. In this case, Pin 7 is connected to Pin 8 as shown
in figure 4, and the R
1
C
1
circuit is omitted.
47
mF/
16 V
C
1
R
1
510
W
R
2
C
2
V
Batt
1
2
6
5
8
7
3
4
13311
U6049B
Figure 3. Basic circuit for 12 V voltage supply and oscillator
R
2
C
2
V
Batt
1
2
6
5
8
7
3
4
13312
V
S
= 5 V
U6049B
Figure 4. Basic circuit for V
S
= 5 V
U6049B
TELEFUNKEN Semiconductors
Rev. A3, 04-Feb-97
3 (8)
Oscillator, Pin 6
Oscillator frequency, f, is determined mainly by
R
2
C
2
-circuit. Resistance R
2
determines the charge time,
whereas the integrated resistance (2 k
W) is responsible
for discharge time. For the stability of the oscillator
frequency, it is recommended to select R
2
much greater
than internal resistance (2 k
W), because the temperature
response and the tolerances of the integrated resistance
are considerably greater than the external resistance
value.
Oscillator frequency, f, is calculated as follows:
f
+
1
t
1
) t
2
where
t
1
= charge time =
a
1
R
2
C
2
t
2
= discharge time =
a
2
@2 kW
@
C
2
a
1
and
a
2
are constants and has
a
1
= 0.833 and
a
2
= 1.551 when C
2
= 470 pF to 10 nF
a
1
= 0.746 and
a
2
= 1.284 when C
2
= 10 nF to 4700 nF
Debounce time, t
3
, and the delay time, t
d
, depend on the
oscillator frequency, f, as follows:
t
3
+ 6 1
f
t
d
+ 73728 1
f
Table 1 shows relationships between t
3
, t
d
, C
2
, R
2
and
frequencies from 1 Hz to 20 kHz.
Output, Pin 2
Output Pin 2 is an open-collector Darlington circuit with
integrated 23-V Z-diode for limitation of the inductive
cutoff pulse of the relay coil. The maximum static
collector current must not exceed 300 mA and the satura-
tion voltage is typically 1.1 V @ 200 mA.
Interference Voltages and Load-Dump
The IC supply is protected by R
1
, C
1
, and an integrated
Z-diode, while the inputs are protected by a series resistor,
integrated Z-diode and RF-capacitor.
The relay control output is protected via the integrated
23-V Z-diode in the case of short interference peaks. It is
switched to conductive condition for a battery voltage of
greater than approx. 40 V in the case of load-dump. The
output transistor is dimensioned so that it can withstand
the current produced.
Power-on Reset
When the operating voltage is switched on, an internal
power-on reset pulse (POR) is generated which sets the
logic of the circuits to a defined initial condition. The
relay control output is disabled.
7 V
15 pF
20 k
W
+
2 V
Pin 3
20 k
W
94 8813
100 nF
Ignition
Terminal 15
Figure 5. Input circuit for ignition (Pin 3)
7 V
15 pF
+
Pin 4, 5
94 8815
Figure 6. Input circuit Pin 4 and Pin 5
Relay Control Output behavior, Pin 2
The U6049B controls the cooling fan motor in an automo-
bile by means of a relay.
Figure 5 shows the internal input circuit of ignition
(Pin 3). It has an integrated pull-down resistor (20 k
W),
RF-capacitor (15 pF) and 7-V Z-diode. It reacts to volt-
ages greater than 2 V.
For the programming input, Pin 5, and thermal switch
input, Pin 4, there is neither a pull-up nor pull-down resis-
tor integrated internally (see figure 6).
One can reduce the standby current through the internal
Z-diode by selecting a higher value for resistance R
4
(see
figure 8, R
4
up to 200 k
W). Resistance R
5
determines the
contact current through the thermal control switch, S
th
.
Ignition input (terminal 15) is not debounced. De-
bouncing can be achieved by an external circuit (R
3
,C
3
)
connected to Pin 3 (see figures 1 and 7).
U6049B
TELEFUNKEN Semiconductors
Rev. A3, 04-Feb-97
4 (8)
94 8817
Ignition
closed
open
Delay time
(internal)
Pin 5=V
stab
:
Relay
Pin 5 = GND:
Relay
V
Batt
S = t
d
Pin 5 = Programming Pin
Pin 3
Pin 4
Pin 2
Pin 2
S
th
t
d
is stopped, if S
th
is open
Figure 7. Timing waveform
The programming input (Pin 5) is high-ohmic and should
therefore be connected to Pin 7 (V
stab
) or GND. The relay
control output is shown according to Pin 5 connection.
Thermal switch input, Pin 4, is debounced (see figure 1).
Relay control output, Pin 2, is disabled when the battery
voltage, V
Batt
, is applied. Relay control output follows the
conditions of the switch, S
th
, only when the ignition is
switched-ON. This is possible only after the debounce
time, t
3.
In this case Pin 5 is connected to Pin 7.
Timing waveforms are shown in figure 4. Total delay
time, t
d
, is the sum of all ON-pulses caused by the thermo-
static switching. This can run down at once or in parts. If
S
th
(Pin 4) is open, the oscillator is stopped (switched-off)
internally, but when it starts (S
th
closed), the delay time,
t
d
, starts running again. In case of renewed switching of
ignition, the counter of the delay time is reset.
47
mF
R
1
510
W
V
Batt
1
2
6
5
8
7
3
4
94 8812
2 k
W
200 k
W 100 nF
C
2
100 nF
C
3
R
4
20 k
W R
3
R
5
Thermal
switch
Terminal 15
C
1
R
2
S
th
U6049B
Figure 8. R
4
= 2 k
W to 200 kW
Basic circuit
U6049B
TELEFUNKEN Semiconductors
Rev. A3, 04-Feb-97
5 (8)
Absolute Maximum Ratings
Parameters
Symbol
Value
Unit
Operating voltage, static, 5 min
V
Batt
24
V
Ambient temperature range
T
amb
40 to +125
C
Storage temperature range
T
stg
55 to +125
C
Junction temperature
T
j
150
C
Thermal Resistance
Parameters
Symbol
Maximum
Unit
Junction ambient
DIP8
SO8
R
thJA
R
thJA
110
160
K/W
K/W
Electrical Characteristics
V
Batt
=13.5 V, T
amb
= 25
C, reference point ground, figure 2, unless otherwise specified
Parameters
Test Conditions / Pin
Symbol
Min
Typ
Max
Unit
Operating voltage
R
1
w 510 W
t < 5 min
t < 60 min
V
Batt
6
16
24
18
V
5 V supply
Without R
1
, C
1
figure 2b
Pins 7 and 8
V
8
, V
7
4.3
6.0
V
Stabilized voltage
Pin 7
V
7
5.0
5.2
5.4
V
Undervoltage threshold
Power-on reset
V
S
3.0
4.2
V
Supply current
Push buttons open
Pin 8
I
S
1.3
2.0
mA
Internal Z-diode
I
8
= 10 mA
Pin 8
V
Z
13.5
14
16
V
Relay output
Pin 2
Saturation voltage
I
2
= 200 mA
I
2
= 300 mA
V
2
1.2
1.5
V
Leakage current
V
2
= 14 V
I
lkg
2
100
mA
Output current
I
2
300
mA
Output pulse current
Load dump pulse
I
2
1.5
A
Internal Z-diode
I
2
= 10 mA
V
2
20
22
24
V
Oscillator input
f = 0.001 to 40 kHz, see table 1 Pin 6
Internal discharge resistance
R
6
1.6
2.0
2.4
k
W
Switching voltage
Lower
Upper
V
6L
V
6H
0.9
2.8
1.1
3.1
1.4
3.5
V
Input current
V
6
= 0 V
I
6
1
mA
Switching times
Debounce time
t
3
5
7
cycles
Delay time
t
d
72704
74752
cycles
Inputs
Pin 3, 4, 5
Switching threshold
V
3,4,5
1.6
2.0
2.4
V
Internal Z-diode
I
3, 4, 5
= 10 mA
V
3,4,5
6.5
7.1
8.0
V
Ignition input
Pin 3
Pull-down resistance
Switched to V
Batt
( 15)
R
3
13
20
50
k
W
Thermal switch
Pin 4
Input current
V
4
= 0 V
I
4
2
mA
Programming input
Pin 5
Input current
V
5
= 0 V
I
5
2
mA
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