HA16116FP Datasheet, PDF (14/34 Pages) Hitachi Semiconductor – Switching Regulator for Chopper Type DC/DC Converter

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^{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
C_T, E/O, and DB pins and enabling quick shutoff.
PWM
output
On
PWM
output
off
PWM output on
PWM
output off
Off
1.7 2.0 2.5
5.0 7.0
Vref (V)
When V_IN is
low
Abnormal voltage
applied to Vref
Relation of Vref to UVL and OVP
V_IN
Vref
Vref
generation
circuit
OVP
2.0 V and
Vref
1.7 V
detection
ZD
5.6 V
R
Internal
pulse
signal
line
UVL
OUT
Sink
10 kΩ
transistor
To other circuitry
Figure 5.1 Quick Shutoff
OUT
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