ld7575ps Leadtrend Technology, ld7575ps Datasheet - Page 12

• Manufacturer Part Number: ld7575ps
• Description: Green-mode Pwm Controller With High-voltage Start-up Circuit
• Manufacturer: Leadtrend Technology

Leadtrend Technology Corporation
LD7575-DS-04b November 2007
Fig. 20
i
=
Cgd
⋅
dV
www.leadtrend.com.tw
dt
bulk
12
Protection Resistor on the Hi-V Path
In some other Hi-V process and design, there may cause a
parasitic SCR between HV pin, Vcc and GND. As shown
in figure 22, a small negative spike on the HV pin may
trigger this parasitic SCR and causes the latchup between
Vcc and GND. And such latchup is easy to damage the
chip because of the equivalent short-circuit which is induced
by such latchup behavior.
Thanks to the Leadtrend’s proprietary Hi-V technology,
there is no such parasitic SCR in LD7575.
shows the equivalent circuit of LD7575’s Hi-V structure.
So that LD7575 is with higher capability to sustain negative
voltage than similar products. However, a 10KΩ resistor is
recommended to implement on the Hi-V path to be played
the role as a current limit resistor whenever a negative
voltage is applied in any case.
Fig. 21
Fig. 22
LD7575
Figure 23