1 Features

• No isolated secondary supply required

• Drives external power transistors or SCRs

• 3-kVRMS basic isolation

• 10-V gate drive with 1.5/3-A peak source and sink

current

• Up to 50-mW supply for external auxiliary circuitry

• Supports AC or DC switching

• Supports two-wire or three-wire modes

• Seven levels of power transfer, resistor selectable

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Temperature range –40 to 125°C ambient

• Safety-related certifications

– Planned: 4243-VPK basic isolation per DIN EN

IEC 60747-17 (VDE 0884-17)

– Planned: 3-kVRMS isolation for 1 minute per UL

1577

2 Applications

• Solid State Relays (SSR)

• Building automation

• Factory automation and control

3 Description

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.