RT6296A
condition continues for a period of time, the RT6296A
will enter output under-voltage protection with hiccup
mode. During hiccup mode, the device remains shut
down. After a period of time, a soft-start sequence for
auto-recovery will be initiated. Upon completion of the
soft-start sequence, if the fault condition is removed,
the converter will resume normal operation; otherwise,
such cycle for auto-recovery will be repeated until the
fault condition is cleared. Hiccup mode allows the
circuit to operate safely with low input current and
power dissipation, and then resume normal operation
as soon as the over-load or short-circuit condition is
removed. The UVP profile is shown in Figure 5.
Over-Temperature Protection
Over-temperature protection is implemented to prevent
the chip from operating at excessively high
temperatures. When the junction temperature is higher
Abnormal case
detected (UV)
V
OUT
0.5ms
1.8ms
than 150C, the OTP will shut down switching
operation. The chip will automatically resume normal
operation with a complete soft-start sequence once the
junction temperature cools down by approximately
20C.
BOOT UVLO
The RT6296A implements BOOT UVLO function to
ensure the V
BOOT-SW
is sufficient to correctly activate
the high side switch at any condition. BOOT UVLO
usually actives at higher V
OUT
, very light load and small
TTH threshold. With such conditions, the low side
switch may not have sufficient turn-on time to charge
the BOOT capacitor. The BOOT UVLO actives when
V
BOOT-SW
is lower than 2.65V (typ.), the device will be
forced to turn on the low side switch for 200ns (typ.) to
charge the BOOT capacitor. The BOOT UVLO
behavior continues for each PWM cycle until the
V
BOOT-SW
is higher than 2.9V (typ.).
SW
Figure 5. Output Under-Voltage Protection with Hiccup Mode
Copyright © 2018 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
www.richtek.com
6
DS6296A-04
January 2018
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
