ld7577gs Leadtrend Technology, ld7577gs Datasheet - Page 14

• Manufacturer Part Number: ld7577gs
• Description: High Voltage Green-mode Pwm Controller With Brown-out Protection
• Manufacturer: Leadtrend Technology

Protection Resistor on the Hi-V Path
In some other Hi-V processes and designs, there is
probably some parasitic SCR caused around HV pin, V
Leadtrend Technology Corporation
LD7577-DS-01 January 2009
Fig. 22
Fig. 23
i
=
Cgd
⋅
dV
www.leadtrend.com.tw
dt
bulk
CC
14
and GND. As shown in figure 24, a small negative spike in
the HV pin may trigger this parasitic SCR and cause the
latchup between V
the chip easily because of the equivalent short-circuit
induced.
The LD7577 has eliminated the parasitic SCR efficiently.
Figure 25 shows the equivalent circuit of the LD7577’s Hi-V
structure. It tells the LD7577 is capable to sustain negative
voltage and superior than similar products. Even though, a
40KΩ resistor is still recommended to be placed on the Hi-V
path
CC
and GND. Such latchup will damage
Fig. 24
Fig. 25
LD7577