HA16116FP/FPJ, HA16121FP/FPJ
5.2 Quick Shutoff
When the UVL circuit goes into operation, a sink transistor is switched on as in the figure below, drawing
off the excess current. This transistor also functions when the IC is turned off, drawing off current from the
CT, E/O, and DB pins and enabling quick shutoff.
PWM
output
PWM
output
off
PWM output on
PWM
output off
On
Off
Vref (V)
1.7 2.0 2.5
5.0
7.0
When VIN is
low
Abnormal voltage
applied to Vref
Relation of Vref to UVL and OVP
Vref
VIN
Vref
2.0 V and
1.7 V
detection
Vref
generation
circuit
Internal
pulse
signal
line
ZD
5.6 V
UVL
OUT
OUT
R
Sink
transistor
10 kΩ
OVP
To other circuitry
Figure 5.1 Quick Shutoff
Rev.2.0, Sep.18.2003, page 14 of 33
RENESAS [ RENESAS TECHNOLOGY CORP ]
