TPIC46L01

The TPIC46L01, TPIC46L02, and TPIC46L03 are low-side predrivers that provide serial input interface and parallel input interface to control six external field-effect transistor(FET) power switches such as offered in the Texas Instruments TPIC family of power arrays. These devices are designed primarily for low-frequency switching, inductive load applications such as solenoids and relays. Fault status for each channel is available in a serial-data format. Each driver channel has independent off-state open-load detection and on-state shorted-load/short-to-battery detection. Battery overvoltage and undervoltage detection and shutdown are provided. Battery and output load faults provide real-time fault reporting to the controller. Each channel also provides inductive-voltage-transient protection for the external FET.

These devices provide control of output channels through a serial input interface or a parallel input interface. A command to enable the output from either interface enables the respective channel GATE output to the external FET. The serial input interface is recommended when the number of signals between the control device and the predriver must be minimized, and the speed of operation is not critical. In applications where the predriver must respond very quickly or asynchronously, the parallel input interface is recommended.

For serial operation, the control device must transition CS\ from high to low to activate the serial input interface. When this occurs, SDO is enabled, fault data is latched into the serial input interface, and the FLT\ flag is refreshed.

Data is clocked into the serial registers on low-to-high transitions of SCLK through SDI. Each string of data must consist of 8 bits of data. In applications where multiple devices are cascaded together, the string of data must consist of 8 bits for each device. A high data bit turns the respective output channel on and a low data bit turns it off. Fault data for the device is clocked out of SDO as serial input data is clocked into the device. Fault data consists of fault flags for the over-battery voltage (bit 8), under-battery voltage (bit 7) (not on TPIC46L03), and shorted/open-load flags (bits 1-6) for each of the six output channels. A logic-high bit in the fault data indicates a fault and a logic-low bit indicates that no fault is present on that channel. Fault register bits are set or cleared asynchronously to reflect the current state of the hardware. The fault must be present when CS\ is transitioned from high to low to be captured and reported in the serial fault data. New faults cannot be captured in the serial register when CS\ is low. CS\ must be transitioned high after all of the serial data has been clocked into the device. A low-to-high transition of CS\ transfers the last 6 bits of serial data to the output buffer, puts SDO in a high-impedance state, and clears and reenables the fault register. The TPIC46L01/L02/L03 was designed to allow the serial input interfaces of multiple devices to be cascaded together to simplify the serial interface to the controller. Serial input data flows through the device and is transferred out SDO following the fault data in cascaded configurations.

For parallel operation, data is asynchronously transferred directly from the parallel input interface (IN0-IN5) to the respective GATE output. SCLK or CS\ are not required for parallel control. A 1 on the parallel input turns the respective channel on, where a 0 turns it off. Note that either the serial interface or the parallel interface can enable a channel. Under parallel operation, fault data must still be collected through the serial data interface.

The predrivers monitor the drain voltage for each channel to detect shorted-load or open-load fault conditions in the on and off states respectively. These devices offer the option of using an internally generated fault-reference voltage or an externally supplied VCOMP for fault detection. The internal fault reference is selected by connecting VCOMPEN to GND and the external reference is selected by connecting VCOMPEN to V_CC. The drain voltage is compared to the fault-reference voltage when the channel is turned on to detect shorted-load conditions and when the channel is off to detect open-load conditions. When a shorted-load fault occurs using the TPIC46L01 or TPIC46L03, the channel is turned off and a fault signal is sent to FLT\ as well as to the serial fault-register bit. When a shorted-load fault occurs while using the TPIC46L02, the channel transitions into a low-duty cycle, pulse-width-modulated (PWM) signal as long as the fault is present. Shorted-load conditions must be present for at least the shorted-load deglitch time, t_(STBDG), in order to be flagged as a fault. A fault signal is sent to FLT\ as well as the serial fault register bit. More detail on fault detection operation is presented in the device operation section of this data sheet.

The TPIC46L01 and TPIC46L02 provide protection from over-battery voltage and under-battery voltage conditions irrespective of the state of the output channels. The TPIC46L03 provides protection from over-battery voltage conditions irrespective of the state of the output channels When the battery voltage is greater than the overvoltage threshold or less than the undervoltage threshold (except for the TPIC46L03, which has no undervoltage threshold), all channels are disabled and a fault signal is sent to FLT\ as well as to the respective fault register bits. The outputs return to normal operation once the battery voltage fault has been corrected. When an over-battery/under-battery voltage condition occurs, the device reports the battery fault, but disables fault reporting for open and shorted-load conditions. Fault reporting for open and shorted-load conditions are reenabled after the battery fault condition has been corrected.

These devices provide inductive transient protection on all channels. The drain voltage is clamped to protect the FET. This clamp voltage is defined by the sum of V_CC and turn-on voltage of the external FET. The predriver also provides a gate-to-source voltage (V_GS) clamp to protect the GATE-source terminals of the power FET from exceeding their rated voltages.

These devices provide pulldown resistors on all inputs except CS\. A pullup resistor is used on CS\.