The TPSI31P1-Q1 is designed to be used in automotive pre-charge systems as an alternative to traditional passive pre-charge architectures that typically include costly electromechanical relays (EMR), along with bulky, high power resistors. The TPSI31P1-Q1, combined with external power switches, power inductor and diode, forms an active pre-charge solution. The inductor current is continuously monitored and controlled in a hysteretic mode of operation by the TPSI31P1-Q1 to linearly charge the large capacitance of the downstream system. The TPSI31P1-Q1 is an isolated switch driver that generates its own secondary bias supply from power received on its primary side, therefore no isolated secondary supply is required. With a gate drive voltage of 17V with 1.5 and 2.5A peak source and sink current, a large availability of power switches can be used including SiC FET and IGBT.

The TPSI31P1-Q1 integrates a communication back-channel that transfers status information from the secondary side to the primary side via open-drain output, PGOOD (Power Good) and indicates when the secondary power is valid.

The Functional Block Diagram shows the primary side includes a transmitter that drives an alternating current into the primary winding of an integrated transformer which transfers power from the primary side to the secondary side. The transmitter operates at high frequency (80MHz, nominal) to optimally drive the transformer to its peak efficiency. In addition, the transmitter utilizes spread spectrum techniques to greatly improve EMI performance allowing many applications to achieve CISPR 25 - Class 5. During transmission, data information is transferred to the secondary side alongside with the power. On the secondary side, the voltage induced on the secondary winding of the transformer, is rectified and multiplied, and is regulated to the voltage level of VDDH. Lastly, the demodulator decodes the received data information and drives VDRV high or low, respective of the logic state of the EN pin.

During each transfer of power from the primary side to the secondary side, back-channel state information is automatically sampled, encoded, and sent from the secondary side back to the primary side where it is decoded.