TPIC71004TDCAQ1中文资料德州仪器数据手册PDF规格书

1FEATURES

2• Quad-Channel Squib Drivers for Airbag

Application

• Loop Diagnostics Monitor and Reporting

• Two Logic Inputs Providing Independent

Safety Logic for Enabling/Disabling

Deployment

• Four Independent Thermally Protected

High-Side Drivers That can Source

Deployment or Diagnostic Current Level to

Each Squib Load

• Four Independent Avalanche Voltage and

Thermally Protected Low-Side Drivers That

Can Sink Deployment or Diagnostic Current

Level From Each Squib Load

• Each Output Capable of 1.2 A/1.75 A Firing

Current for Typical 2 ms/0.5 ms

• SPI Slave Interface for Serial Bus

Communication with Parity Check

• Firing VZx Voltage Range 10 V to 35 V,

Transients up to 40 V

• Programmable Firing Time up to 8.2 ms

• Common Load Current Settings for All

Deployment Loops, Using Registers

• Individual Firing Current Timer Limit Set for

Each Deployment Loop, Using Registers

• Firing Current Timer to Monitor Firing Current

Over Deployment Time for Each Deployment

Loop

• Independent Switch Control for Both High- and

Low-Side Switches

• Diagnostic Mode for Fault Checking

• Internal Fault Monitoring for Safe Operation

• A Multiplex-able Output Buffer for Analog

Voltage Measurements

• Use of External Clamping devices on Squib

Pins is Not Required to Protect the

Deployment ASIC Against Substrate Injection

Effects During Deployment Due to Dynamic

Shorts to Ground

• An External Pin Connection to the

Microprocessor ADC Supply for Ratio-metric

Squib Resistance Measurement

• 40-V Pin Capability on All Pins (Except GNDx,

AGND, DGND, VCC5, VDDIO, AMX_OUT)

• Operating Ambient Temperature Range: –40°C

to 105°C

• Thermally Enhanced 48-Pin TSSOP DCA

PowerPad™ Package

APPLICATIONS

• Squib Drivers for Airbag Application

DESCRIPTION

The TPIC71004-Q1 is a quad channel squib driver for airbags deployment in automotive applications. Each

channel consists of a high side and a low side switch with independent control logic for protection against

inadvertent deployment. Both the high and the low side switches have internal current limits, over-temperature

protection.

The IC registers are used for four channel configuration, control and status monitoring. To prevent inadvertent

deployment, the high and the low side switches will be turned on only if the proper configuration sequence is

used and multiple inputs to the deploy controller logic are at the correct level. The registers are programmed

using a serial communications interface.

The maximum on time for each channel is limited by programmable Firing Time Out Timer to prevent excessive

power dissipation. In addition, a current limit register is used to program the maximum current through the

switches during a deployment. The current limitation on the low side switch is larger than the corresponding high

side switch. During deployment, the low side switch will be full enhanced and operate with RDS_ON mode and

the high side switch will be in current regulation mode.

The implemented diagnostic functions monitor deployment ASIC pin voltages to provide High Side switch test,

Low Side switch test, squib resistance measurements, squib leakage measurement to battery, ground and

between any squib channels. Furthermore, the squib leakage measurement is provided for both Zx and ZMx pins

and does not require the squib load to be present to operate properly. Diagnostic information is communicated

through the AMX_OUT pin (for analog signals) and SPI mapped status registers (for status signals latched in

digital core).

The high-side and low-side squib drivers have a diagnostic level current limit and a deployment level current limit.

The default current limit for high-side and low-side squib drivers is the diagnostic level current limit. The high-side

switch deployment current limit for all high-side drivers can be set to either 1.2 A min or 1.75 A min (see Table 1)

through SPI mapped registers, device EEPROM settings (see Table 2). The low-side switch deployment current

limit is not programmable and is fixed to a level greater than the high-side driver current limit. The ON time

duration for each individual squib driver can be programmed through SPI mapped registers.

The deployment sequence requires a specific set of software commands combined with external hardware

enable logic lines (TZ0=H, IWD=L) to provide deployment capability. The turn-on sequence of the high-side

driver and low-side drivers is software controlled via SPI commands, but the turn-off procedure is automatically

provided by the deployment ASIC. After the programmed ON time duration has been achieved, the high-side

switch is deactivated first then followed by the low-side driver deactivation by approximately 100μsec.

The RESET_N is an active low input reset signal. This input will be released high by the power supply unit and/or

the μC once the external voltage supplies are within the specified limits. The external microcontroller is required

to configure and control device through the serial communication interface. Reliable software is critical for the

system operation.