ld7522 Leadtrend Technology, ld7522 Datasheet - Page 14

• Manufacturer Part Number: ld7522
• Description: Smart Green-mode Pwm Controller With Multiple Protections
• Manufacturer: Leadtrend Technology

When the V
(typical 2.5V), LD7522 will shutdown the gate output and
then latch-off the power supply. On LD7522, the controller
will be kept latched until the Vcc drop lower than 8V (power
down reset) and the fault condition is removed.
means the gate output is still off even the abnormal
condition is released. The only way to successfully re-start
the circuit needs to meet 2 conditions. One is to cool down
the circuit thus NTC resistance is increased then V
higher than 3.5V. Another condition is to remove the AC
power cord and begin another AC power-on recycling. The
detail operation is depicted as figure 29.
Leadtrend Technology Corporation
LD7522-DS-03 January 2008
(-)LATCH
is lower than the threshold voltage
Fig. 29
www.leadtrend.com.tw
(-)LATCH
That
is
14
Summary of Protections
There are several ways to control the on/off of LD7522. The
details are listed as the table below.
COMP
OLP
OVP
Brownout
OTP
Comp Pin <
1.4V
Comp Pin >
5.0V
OVP Pin >
2.5 V
BNO Pin <
1.25V with
Hysteresis
(-)LATCH Pin
< 2.5V
Turn Off
Table 1
Cycle by Cycle Mode
Non-latch
Hiccup Mode
Non-latch
Re-start after next UVLO(on)
Latch Mode
LD7522
Operation