DS9746 Datasheet, PDF (2/10 Pages) Richtek Technology Corporation – VBUS OVP with a PTVS Diode

RT9746
Functional Pin Description
Pin No
A1
A2, A3, B2
B1
A4, B4, C4
B3, C2, C3
C1
Pin Name
GND
VOUT
WRNB
GND_PTVS
VIN
OVPFB
Pin Function
Common Ground Of Internal Circuits.
Output from VBUS Load-Switch.
Inverse Warning Signal (OCP,OTP, OVP, UVLO) Flag Output (Open-Drain).
Common Ground of Power TVS Diode.
VBUS from Power Adaptor.
External OVP Adjustment Setting. (if no used, be surely tied to GND)
Function Block Diagram
VOUT
GND
Power
FET
OCP
OTP
UVLO
OVPFB
OVP
SEL
External
& Internal
OVP
Digital
Control
Pre-
Regulator
POR
I/O Buffer
VIN
GND_PTVS
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.
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DS9746-00 March 2016