U6046B Datasheet, PDF (3/11 Pages) TEMIC Semiconductors – Rear Window Heating Timer

U6046B / U6047B
Oscillator, Pin 6
Oscillator frequency, f, is determined mainly by the
W ^{R2C2 circuit. Resistance, R2, determines the charge time,}
and the integrated resistance (2 k ) is responsible for dis-
charge time. For the stability of the oscillator frequency,
W ^{it is recommended that the selected R2 value be much}
greater than the internal resistance (2 k ) 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
t₁ t₂
where
a t₁ = charge time = ₁ R₂ C₂
a W t₂ = discharge time = ₂ 2 k C₂
a a ₁ and ₂ are constants as such
a a ₁ = 0.833 and ₂ = 1.551 when C₂ = 470 pF to 10 nF
a a ₁ = 0.746 and ₂ = 1.284 when C₂ = 10 nF to 4700 nF
The debounce time, t₃, and the delay time, t_d, depend on
the oscillator frequency, f, as follows:
+t₃ 6
1
f
+t_d 73728
1
f
Table 1 shows relationships between t₃, t_d, C₂, R₂ and
frequencies from 1 Hz to 20 kHz.
Relay Control Output
The relay control output is an open collector Darlington
circuit with an integrated 23-V Z-diode for limitation of
the inductive cut-off pulse of the relay coil. The
maximum static collector current must not exceed 300
mA and saturation voltage is typically 1.1 V @ 200 mA.
Interference Voltages and Load-Dump
The lC supply is protected by R₁, C₁, and an integrated
Z-diode, while the inputs are protected by a series resistor,
integrated Z-diode and RF capacitor (refer to Figures 10
and 11).
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 output is disabled.
V_Batt
R₁ 510 W
C₂
C₁
R₂
47 mF/
16 V ₈
7
6
S1
20 kW
5
V_Batt
U6046B
1
2
3
4
94 8751
R₁ 510 W
C₁
47 mF/
16 V ₈
7
C₂
R₂
6
S1
2 kW
5
U6047B
1
2
3
4
94 8752
Figure 5. TOGGLE function U6046B
Figure 6. TOGGLE function U6047B
TELEFUNKEN Semiconductors
Rev. A2, 03-Feb-97
3 (11)