LV52207NXA Datasheet, PDF (10/18 Pages) ON Semiconductor – Dual channel LED Boost Driver

LV52207NXA
PWM Mode
The dimming mode is set to PWM mode when it is not recognized as a digital mode within Tsel. The LV52207NXA
can receive the PWM signals at the PWM pin (PWM interface)(PWM Mode) for brightness dimming. When using
PWM interface, the EN pin should be kept high. If EN pin is H, PWM pin alone is used to enable and disable the IC.
When EN pin is H and PWM pin is H , this IC is enable. When EN pin more than 2.5ms are low or when PWM pin
more than 20ms are low, the IC is disable.
Fig6. Start up and shutdown diagram (PWM MODE)
LEDO1 or LEDO2 UNUSED
If only one channel is used, a user can be made to OFF by connecting to ground the unused channel. If LEDO1 pin and
LEDO2 pin are connected to ground, dcdc will not start up.
Over Voltage Protection ( SW OVP)
SW pin over-voltage protection is set at 37.5V. This IC monitors the Voltage at SW pin. When the voltage exceed
OVP threshold, the switching converter stops switching.
If SW terminal voltage exceeds a threshold Vovp (37.5V typ) for 8 cycles, boost converter enters shutdown mode. In
order to restart the IC, SWIRE signal is required again.
Over Voltage Protection ( LEDO OVP)
LED pin over-voltage protection is set at 4.5V(rise) 3.5V(fall). This IC monitors the Voltage at LEDO1 pin and
LEDO2 pin. When the voltage exceed LEDO OVP threshold, the switching converter stops switching. LED current
sink keep.
Open LED Protection
< When one LED string becomes open.>
If one LED string is open, open channel voltage is about ground, the boost output voltage is increased and other
LEDO channel voltage is increased. When SW pin voltage is reached the SW OVP threshold the LV52207NXA’s
switching converter stops switching. When other LEDO pin voltage is reached the LEDO OVP threshold, the
LV52207NXA’s switching converter stops switching.
< When both LED strings become open.>
If both LED strings are open, LEDO1 pin voltage and LEDO2 pin voltage is about ground, and the boost output
voltage is increased
When SW pin voltage is reached the SW OVP threshold the LV52207NXA’s switching converter stops switching.
Over Current Protection
Current limit value for built-in power MOS is around 1.5A. The power MOS is turned off for each switching cycle
when peak current through it exceeds the limit value.
Under Voltage Lock Out (UVLO)
UVLO operation works when VIN terminal voltage is below 2.2V.
Thermal Shutdown
When chip temperature is too high, boost converter is stopped.
No.A2346-10/18