AR2003FV_15 Datasheet, PDF (12/15 Pages) Diodes Incorporated – ACTIVE/SYNCHRONOUS RECTIFICATION CONTROLLER

AR2003FV
Application Information
ON Timer Programming
The Ton period (minimum on-time) is programmed by adding a resistor from TON pin to ground. In the application, it’s likely that when the MOSFET
is turned on there will be some ringing generated due to parasitic within the system. The minimum on time will stop the device reacting to this
ringing, by blanking out any signal received from the Drain to Source (VD-VS) comparator once the device is initially triggered. This will keep the
MOSFET turned on for duration of the minimum on-time, irrespective of the VD-VS voltage during this period.
If VD-VS reaches the gate turn-off threshold within the minimum on-time period, the device will change into Light Load Mode for the next switching
cycle. If the load conditions of the system change and the MOSFET turn-off threshold is once again reached once the minimum on-time is over, the
device reverts to its nominal mode of operation.
TON (μs) = 0.028μs * RTON (KΩ) + 0.1μs, 0.24μs < TON < 4.3μs, 5KΩ < RTON <150KΩ
Enabling and OFF Timer Programming
When VCC < UVLO, TOFF/EN is internally connected to ground through a resistor.
If VCC rises above UVLO, the chip is in the Sleep Mode, a current source will deliver 20µA (IEN-START) to TOFF/EN pins. If RTOFF > 70KΩ, VTOFF/EN
will over 1.4V (VEN-ON), AR2003FV will enter Active Mode. And the internal current source will switch to deliver 10µA (IEN-ON) to TOFF/EN pin. User
can program the minimum off-time by choosing proper value for RTOFF.
TOFF (µs) = 0.083µs* (RTOFF (KΩ)-81KΩ), valid for 85KΩ < RTOFF < 200KΩ
User can also program OFF timer by control the VTOFF/EN.
TOFF (µs) = 0.083µs* (VTOFF/EN-0.81V), valid for 0.85V < VTOFF/EN < 2V
The minimum off-time is the minimum time; the internal MOSFET will be turned off once VTHOFF turn off threshold is reached. This avoids the
MOSFET accidentally being retriggered by ringing after turn off.
Minimum
on time
No load mode VDS waveform
Minimum
off time
Maximum load mode VDS waveform
T_FSW
Maximum
on time
VDS=VTHON =-150mV
VDS=VTHON=-150mV
VDS=VTHOFF
VDS=VTHARM=1.5V
Minimum On Time
>The time from VDS fall under VTHON to VDS ringing voltage <
VTHOFF
Maximum On Time
< The time from VDS fall under VTHON to VDS =VTHOFF
Minimum Off Time
> The time from VDS > VTHARM to VDS ringing negative voltage
higher than VTHON after turn off
Maximum Off Time
< The time from VDS=VTHARM to VDS drop from VCC level
VDS=VTHARM=1.5V
Maxima
off time
Check with no load waveform
Check with no load waveform
Check with no load waveform
Check with maximum load waveform
AR2003FV
Document number: DS37473 Rev. 3 - 2
12 of 15
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December 2014
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