Datasheet

UCC24610

SLUSA87B –AUGUST 2010–REVISED SEPTEMBER 2010

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TERMINAL FUNCTIONS (continued)

TERMINAL

I/O DESCRIPTION

NAME NO.

VCC (Positive Power Input)

Connect a DC power voltage to VCC. Bypass VCC to GND with a 0.1-µF or larger ceramic

capacitor using short PC board tracks. VCC supplies power to all circuits in the UCC24610.

VCC 4 I Under-Voltage Lockout (UVLO) comparators prevent operation until VCC rises above

CC(on)

. VCC can be used to safely turn off the UCC24610 by pulling VCC below V

CC(off)

. In

the event that VCC drops below V

CC(off)

, GATE immediately falls Low and EN/TOFF is

internally connected to GND with a 10-kΩ resistance.

VD (Drain-Sense Voltage)

Connect this pin as close as possible to the controlled MOSFET drain pad through a short

PC board track, to minimize the effects of trace inductance on VD. VD must be >1.5 V and

the TOFF timer must be expired before the device may be armed to allow the controlled

MOSFET to be turned on the next switching cycle. Once armed, the controlled MOSFET is

turned on (GATE goes High) when VD falls more than -150 mV below VS. At that threshold,

VD 8 I the GATE output goes High and the TON timer is triggered. GATE remains High at least as

long as the programmed TON time has not expired, unless a pulse at the SYNC input is

detected. After TON has expired, the GATE output is turned off when VD-VS voltage

decreases to -5 mV. If VD-VS decreases to -5 mV before TON expires, the controller enters

Light-Load Mode and the GATE pulse for the next switching cycle is suppressed. When the

VD voltage increases to 1.5 V, the TOFF timer is triggered and the GATE output is

prevented from turning on during the TOFF interval.

VS (Source-Sense Voltage)

VS 7 I Connect this pin as close as possible to the controlled MOSFET source pad through a short

PC-board track, to minimize the effects of trace inductance on VS.

Product Folder Link(s): UCC24610