The TPSI3100 is a fully integrated isolated switch driver, which when combined with an external power switch, forms a complete isolated solid state relay solution. With a gate drive voltage of 15.8-V with 1.5/2.5-A peak source/sink current, a large availability of power switches can be used to meet many application needs. The TPSI3100 generates its own secondary bias supply from power received on its primary side, so no isolated secondary supply bias is required. The TPSI3100 provides additional power via the nominal 5-V rail (VDDM) for use by auxiliary circuits to perform various function such as current and voltage monitoring or remote temperature detection. The TPSI3100 isolation is extremely robust with much higher reliability, lower power consumption, and increased temperature ranges than those found using traditional mechanical relays and optocouplers.

The TPSI3100 integrates a communication back-channel that transfers status information from the secondary side to the primary side via open-drain outputs, PGOOD (Power Good), FLT1 (Fault 1), and ALM1 (Alarm 1). Dual high-speed comparators with an integrated shared voltage reference are used to assert FLT1 and ALM1. When the comparator input, FLT1_CMP, exceeds the voltage reference, the driver is immediately asserted low and FLT1 is also driven low, indicating to the system that a fault has occurred. This is useful for disabling the external switch with low latency on critical events, such as over-current detection. When the comparator input, ALM1_CMP, exceeds the voltage reference, ALM1 signal is asserted low, but no action is taken by the driver. This may be useful as an alarm or warning indicator for over-temperature or over-voltage events.

The TPSI310xL series offers a latch based fault indicator. When a fault is detected, the driver and the fault indicator are asserted low and remain latched, until EN is asserted low. The TPSI310x series has a non-latched fault indicator. If the fault event is no longer present, FLT1 deasserts and the driver, after a specified recovery period, follows the state of the EN pin. If the fault event still remains, both the fault indicator and the driver remain asserted low.

The TPSI310x and TPSI310xL device family has two voltage options for the integrated reference to meet a wide range of application needs.

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 (80 MHz, 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.