TDA7565_10 Datasheet, PDF (16/19 Pages) STMicroelectronics – Quad power amplifier with integrated step-up converter

Low voltage "start-stop" operation
6
Low voltage "start-stop" operation
TDA7565
The most recent OEM specification are requiring automatic stop of car engine at traffic lights
in order to reduce emissions of polluting substances. The TDA7565, thanks to its integrated
switching voltage converter, allows a continuous operation when battery falls down to 6/7 V
during such conditions, without producing pop noise. The maximum system power will be
reduced accordingly.
The internal converter must be enabled and programmed in order to supply 15 V (D3 (IB2) = 0;
D6 (IB2) = 0). The suggested voltage frequency switching is 150 kHz (D6 (IB1) = 1; D7 (IB1) = 0).
The following curve is a worst case condition for a start-stop system. The TDA7565, with the
switching converter powered on, can sustain this cranking curve without any audio signal
interruption.
Figure 7. Worst case condition for a start-stop system diagram
V
V_b1
V_b3
V_b2
t_r t₁ t₂
t₃
t_f
t
V_b1 = 12 V, V_b2 = 6 V, V_b3 = 7 V
R_i ≤ 0.01 Ω (internal resistor of power supply)
Recovery time from test start to tr is 1 s
t_r = 2 ms
t₁ = 1 ms (the shortest time, at cranking simulation power supply, is 5 ms)
t₂ = 15 ms
t₃ = 1 s
t_f = 0.5 s
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Doc ID 9800 Rev 4