AR2003FV

11 of 15

December 2014

Document number: DS37473 Rev. 3 - 2

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AR2003FV

Modes of Operation

General Description

AR2003FV is an Active/Synchronous Rectifier which can work with many different primary side controllers. AR2003FV can be used in both SSR

and PSR systems.

AR2003FV has preset of internal feedback resistor that can reduce external BOM for 5V or 12V system.

UVLO MODE

When VCC does not reach UVLOTH, or falls blow UVLOTH - UVLOHYS, AR2003FV will be in UVLO MODE.

In this mode, AR2003FV will turn off external MOSFET, and TOFF/EN pin will internally short to GND. VCC current will be ICCSTART.

Sleep Mode

Sleep Mode is a low-power operating mode similar to UVLO Mode, except that this mode is entered by forcing VEN below the VEN-OFF threshold via

external control. Many internal circuits are turned off to reduce power consumption in this model to reduce device operating losses. External control

overrides any internal timing conditions, and immediately forces the GATE output low and enters Sleep Mode. VCC current is reduced to

ICCSTANDBY level. As VEN is restored to above the VEN-ON threshold, the device exits Sleep Mode into Light-Load Mode after a delay of several μs,

allowing re-powered internal circuits to settle.

Active Mode

This is the normal operation mode when inductor current is large enough and synchronous conduction time is longer than TON. AR MOSFET will be

turned on and off according to VD-VS, TON and TOFF setting and SYNC pin.

Light-Load Mode

When Inductor current is small and synchronous conduction time is less than TON, the AR MOSFET will be kept OFF to reduce switching power

loss. Voltage across body diode of AR MOSFET is continuously monitored. When the MOSFET body-diode conduction time is more than TON, the

device will be back to Active mode again.

Over Voltage Protection

Over Voltage mostly likely was an indication of optical coupler short. Therefore, just reporting output error information is not enough. AR2003FV will

drive an external FET to create a short situation so that primary side can be set to whole system to restart.

Over Temperature Protection (Only for Secondary-side Synchronous Rectification Application)

When AR2003FV is over heated, AR2003FV will light up the optical coupler to let the primary side deliver very little or no energy so that the whole

system will cool down. Hysteresis is set to +25°C.

Usually, VCC might drop blow UVLOTH - UVLOHYS (around 2.8V) due to system load. AR2003FV will enter UVLO mode, and system might restart

again. If AR2003FV is over heated again in short time, VCC might be kept around 2.8V. The primary side controller might treat this event as over

current or short current, and enters its protection mode.

Over Current Protection

Over Current Protection is not implemented in AR2003FV. Over Current Protection will be carried out in Primary side.

Short Current Protection

Short Current Protection is not implemented in AR2003FV. Short Current Protection handling will be carried out in Primary side.