1 Features

• Replaces large, high power pre-charge resistors

using a switched converter architecture

• Improved thermal performance compared to

passive pre-charge solutions

• Hysteretic current control for linear charging of

downstream capacitance

• Drives external power transistors such as Si, SiC

MOSFET, or IGBT

• Integrated isolated secondary supply for gate bias

• 17V gate drive, 1.5A and 2.5A peak source and

sink current

• AEC Q-100 qualified for automotive applications:

– Temperature grade 1: –40°C to +125°C, TA

• Functional Safety-Capable

– Documentation available to aid functional safety

system design

• Safety-related certifications

– Planned: 7070VPK reinforced isolation per DIN

EN IEC 60747-17 (VDE 0884-17)

– Planned: 5kVRMS isolation for 1 minute per UL

1577

2 Applications

• Battery management system

3 Description

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 1.5A 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 backchannel

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 TPSI31P1-Q1 reinforced isolation is extremely

robust with much higher reliability, lower power

consumption, and increased temperature ranges than

those found in optocouplers. Replacing the EMR and

power resistor with a solid state solution can lead to

reduced cost and form factor, while providing higher

reliability.