tda3683 NXP Semiconductors, tda3683 Datasheet - Page 11

• Manufacturer Part Number: tda3683
• Description: Tda3683 Multiple Voltage Regulator With Switch And Ignition Buffer
• Manufacturer: NXP Semiconductors

Philips Semiconductors
TDA3683_2
Product data sheet
7.10 Supply voltage inputs
7.9 Ignition buffer
The ignition buffer (pins IGNIN and IGNOUT) is an independent inverting open-collector
output buffer circuit that can be used to sense the start line of the ignition key in a car. The
start line will only be pulled-up to the battery voltage in the event of an engine crank
resulting in a LOW at the inverting output of the ignition buffer. This output signal can be
used to immediately mute an audio amplifier during the engine crank.
To guarantee a reliable LOW output signal, even in extreme cold weather crank conditions
(the battery voltage may momentarily drop down to 3 V) a low supply latch function is
implemented.
To make the ignition buffer input robust, for possible extreme transients present on the
battery line, an input RC filter is strongly advised. A blocking diode is also recommended
to prevent substrate injection in case of negative voltage spikes at the input.
The supply voltage inputs (pins V
Both inputs are protected against load dump transients and reverse battery connections.
The second supply pin (V
switched regulators (REG5 and REG6) and can be connected to an external DC-to-DC
downconverter for reduced power dissipation and increased power supply efficiency.
Power must be applied to pin V
gaps for the switched and standby regulators are connected to this supply pin.
Rising and falling supply voltage threshold levels determine if the switched regulators and
power switch can be switched on.
The timing diagrams for various regulator functions are illustrated in
Figure
5.
Rev. 02 — 7 October 2005
P2
) is internally connected to the high current/ low output voltage
Multiple voltage regulator with switch and ignition buffer
P1
P1
to ensure that the circuits are functional, since the band
and V
P2
) are intended to be connected to the battery.
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Figure 4
TDA3683
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