NCS29001

http://onsemi.com

8

STANDBY ON AND OFF SEQUENCE

Figure 5. Entering Standby Mode

Standby

VIN

Vin IC

PWMin

PWMout

Vfb & I(LED)

GATE

UVLO

Vout

Discharging the

output capacitor

The STBY pin contains an internal 5 M

W pull−up resistor to VREF. This resistor limits current consumption when the device

is in standby mode and also ensures the device will remain in standby if the STBY pin is left floating.

When the STBY goes high the boost converter will stop switching and the PWMout pin will switch, or remain high for 50 ms.

This allows the output capacitor to discharge and the LED current to fall to zero. The device will be in a low power standby

mode and can begin soft start from the next enable sequence.