TI TPIC71004TDCARQ1

TPIC71004-Q1 is a 4-channel squib driver for airbag deployment in automotive applications. Each channel includes a high-side and low-side switch, with independent control logic to prevent inadvertent deployment. Both high-side and low-side switches support internal current limiting and over-temperature protection. IC registers are used for 4-channel configuration, control, and status monitoring. To prevent inadvertent deployment, the high-side and low-side switches can only be activated when the proper configuration sequencing is applied and multiple inputs of the deployment controller logic meet the required levels. The registers are programmed via a serial communication interface. To avoid excessive power dissipation, the maximum on-time per channel is limited by a programmable firing timer. In addition, the current limit register can be used to program the maximum current through the switches during deployment. The current limit on the low-side switch is higher than that of the corresponding high-side switch. During deployment, the low-side switch is fully enhanced and operates in RDS_ON mode, while the high-side switch operates in current regulation mode. Diagnostic functions are implemented to monitor deployment ASIC pin voltages, enabling high-side switch testing, low-side switch testing, squib resistance measurement, and squib leakage measurement for the battery, ground, and any squib channel. In addition, the Zx and ZMx pins provide squib leakage measurement that operates smoothly without a squib load. Diagnostic information is communicated via the AMX_OUT pin (for analog signals) and SPI-mapped status registers (for digitally core-latched status signals). Both high-side and low-side squib drivers have diagnostic-level and deployment-level current limits. The default current limit for both 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 1.2 A (minimum) or 1.75 A (minimum) via SPI-mapped registers and device EEPROM settings. The low-side deployment current limit is not programmable and is fixed at a level greater than the high-side driver current limit. The on-time duration for each individual squib driver can be programmed via SPI-mapped registers. Deployment sequencing requires a specific combination of software commands and external hardware enable logic (TZ=H, IWD=L) to enable deployment functionality. The turn-on sequence of the high-side and low-side drivers can be software-controlled via SPI commands, while the turn-off procedure is handled automatically by the deployment ASIC. After the programmable on-time duration is reached, the high-side switch deactivates first, followed by the low-side driver approximately 100µsec later. RESET_N is an active-low input reset signal. Once the external supply voltage is within specified limits, this input is released high by the power supply unit and/or µc. An external microprocessor is required to configure and control the device via the serial communication interface. Robust software is critical to system operation.

• Four-channel squib driver for airbag applications
• Loop diagnostics monitoring
• Two logic inputs for independent safety logic to enable/disable deployment
• 4 independent thermally protected high-side drivers sourcing deployment or diagnostic current levels to each squib load
• 4 independent avalanche voltage and thermally protected low-side drivers sinking deployment or diagnostic current levels from each squib load
• 1.2 A/1.75 A ignition current per output, typically for 2 ms/0.5 ms
• SPI slave interface supporting serial bus communication with parity
• Ignition VZx voltage range 10 V to 35 V, transient voltage up to 40 V
• Programmable ignition time up to 8.2 ms
• Register-based common load current setting for all deployment loops
• Per-deployment-loop register-configurable individual ignition current timer
• Ignition current limiting timer for monitoring deployment time per deployment loop
• Independent switching control for high- and low-side switches
• Fault detection diagnostic mode
• Internal fault monitoring for safe operation
• Multiplexable output buffer supporting analog voltage measurement
• External clamp device on squib pins; no protection required against substrate injection effects from dynamic short-to-ground during deployment
• Ratiometric squib resistance measurement when deployment ASIC external pins are connected to microprocessor ADC supply
• All pins except GNDx, AGND, DGND, VCC5, VDDIO, and AMX_OUT support 40 V pin capability
• Operating ambient temperature range: -40°C to 105°C
• Thermally enhanced 48-pin TSSOP DCA PowerPad package

• Squib driver for airbag applications