TPD2004F_07 TOSHIBA [Toshiba Semiconductor], TPD2004F_07 Datasheet - Page 5

• Manufacturer Part Number: TPD2004F_07
• Description: 2-channel Squib Driver for Air Bags
• Manufacturer: TOSHIBA [Toshiba Semiconductor]

Functional Description
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2-channel squib drive function
Using independent four-channel inputs, this IC controls two high-side and two low-side switches,
making it possible to drive two squibs directly.
Squib line short-to-battery, short-to-ground and open-circuit diagnostic function (diagnostic voltage
output)
When the squib is in normal state, by an external diagnostic resistor, the device outputs a voltage
derived from V
the analog multiplexer, it is possible to diagnose short-to-battery, short-to-ground and open-circuit in
the squib line using a microcomputer. Also, the device contains a shunt circuit to prevent the analog
multiplexer from breaking down when the squib is short-to-battery.
Squib short diagnostic function (diagnostic voltage output)
A diagnostic current is flowed from the internal constant-current source to the squib and reference
resistor, and the voltage drop in each is amplified by an internal amp whose gain is the same for both.
These voltages are output via the analog multiplexer, so that the squib resistance value can be
diagnosed by a microcomputer. Also, the relative accuracy of the output voltages is guaranteed to be
within ±10%.
Squib driver MOSFET diagnostic function (diagnostic voltage output)
When the squib driver is turned on while the safing sensor is in normal state, the drain voltage of the
MOSFET is output via the analog multiplexer, making it possible to diagnose the state of the
MOSFET using a microcomputer.
Diagnostic chip select function
Since the device has a chip select function, the diagnostic control bits can be minimized when the
application circuit is configured with multiple chips. Furthermore, when a chip is not selected, the
diagnostic output pin AO is placed in the high-impedance state; therefore it is possible to diagnose
multiple chips using a 1-channel CPU A/D port. (Ignition operates irrespective of CS.)
Input INHIBIT function
The purpose of this function is to prevent erroneous ignition due to a fault in the microcomputer or
the system power supply. It allows for ignition to be inhibited by pulling the ENB pin low.
CC
by dividing it according to the resistance ratio. Because this voltage is output via
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TPD2004F
2006-10-31