Isolated switch driver with integrated 10-V gate supply

The TPSI3050 is

a fully integrated, isolated switch driver, which when combined with an external power

switch, forms a complete isolated solid state relay (SSR). With a nominal gate drive voltage

of 10 V with 1.5/3.0-A peak source and sink current, a large

variety of external power switches can be chosen to meet a wide range of applications. The

TPSI3050 generates its own secondary bias supply from

the power received from its primary side, so no isolated secondary supply bias is required.

Additionally, the TPSI3050 can optionally supply power to

external supporting circuitry for various application needs.

The TPSI3050 supports two modes of operation based on the

number of input pins required. In two-wire mode, typically found in driving mechanical

relays, controlling the switch requires only two pins and supports a wide voltage range of

operation of 6.5 V to 48 V. In three-wire mode, the primary supply of 3 V to 5.5 V is

supplied externally, and the switch is controlled through a separate enable. Available in

three-wire mode only, the TPSI3050S features a one-shot

enable for the switch control. This feature is useful for driving SCRs that typically

require only one pulse of current to trigger.

The secondary side provides a regulated, floating

supply rail of 10 V for driving a large variety of power

switches with no need for a secondary bias supply. The application can drive single power

switches for DC applications or dual back-to-back power switches for AC applications, as

well as various types of SCR. The TPSI3050 integrated

isolation protection is extremely robust with much higher reliability, lower power

consumption, and increased temperature ranges than traditional mechanical relays and

optocouplers.

The power transfer of the TPSI3050 can be adjusted by selecting one of seven power

level settings using an external resistor from the PXFR pin to VSSP. This action allows for

tradeoffs in power dissipation versus power provided on the secondary depending on the needs

of the application.