RT9746

2

DS9746-00 March 2016

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Copyright 2016 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Function Block Diagram

Pre-

Regulator

Digital

Control

OCP

VOUT

OVPFB

GND_PTVS

VIN

POR

I/O Buffer

OTP

UVLO

External

& Internal

OVP

Power

FET

OVP

SEL

GND

WRNB

Operation

The RT9746 is a VBUS OVP protector switch. The OVP function is optimized to protect low voltage system from

abnormal high input voltage (up to 28V) in handheld application. RT9746 is also embedded Power-TVS diode (PTVS) on

VBUS pin for surge protection. If surge waveform is above 30V, it will be clamped to 30V due to PTVS diode. When

plugging in VBUS, the OCP will be soft-start in 8ms in order to reduce in rush current and internal VOUT deglitch time

is 16/32/64/128ms which is set by fuse. The OCP after soft-start is up to 4.5A for high current application.

Functional Pin Description

Pin No

Pin Name

Pin Function

A1

GND

Common Ground Of Internal Circuits.

A2, A3, B2

VOUT

Output from VBUS Load-Switch.

B1

WRNB

Inverse Warning Signal (OCP,OTP, OVP, UVLO) Flag Output (Open-Drain).

A4, B4, C4

GND_PTVS

Common Ground of Power TVS Diode.

B3, C2, C3

VIN

VBUS from Power Adaptor.

C1

OVPFB

External OVP Adjustment Setting. (if no used, be surely tied to GND)