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| HA16114P Datasheet, PDF (16/38 Pages) Hitachi Semiconductor – Switching Regulator for Chopper Type DC/DC Converter | |||
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HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
TM
RC
(open)
I IN
VIN
To latch
VIN
To other circuitry
ON/OFF
10 kâ¦
RD
3VBE
GND
Q1
Vref
generation
circuit
Vref output
Q2
Q3
On/off hysteresis circuit
3
2
Vref
1 VOFF
0.7 V
00
1
2.5 V
VIN ⥠4.5 V
VON
1.4 V
2 345
VON/OFF
Figure 6.2 Adjustment of UVL Voltages
7. Timing of Intermittent Mode during Overcurrent
7.1 Principle of Operation
These ICs provide pulse-by-pulse overcurrent protection by sensing the current during each pulse and
shutting off the pulse if overcurrent is detected. In addition, the TM and ON/OFF pins can be used to
operate the IC in intermittent mode if the overcurrent state continues. A power supply with sharp settling
characteristics can be designed in this way.
Intermittent mode operates by making use of the hysteresis of the ON/OFF pin threshold voltages VON and
VOFF (VON â VOFF = VBE). The timing can be programmed as explained below.
When not using intermittent mode, leave the TM pin open, and pull the ON/OFF pin up to VON or higher.
The VBE is base emitter voltage of internal transistors.
390 kâ¦
VIN
RA
TM
2.2 kâ¦
+
2.2 µF â
RB
ON/OFF
CON/OFF
Latch
S
QR
Current
limiter
CL
Vref
reference
Figure 7.1 Connection Diagram (example)
16
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