HA16120 RENESAS [Renesas Technology Corp], HA16120 Datasheet - Page 16

• Manufacturer Part Number: HA16120
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: RENESAS [Renesas Technology Corp]

HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
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 V
V
When not using intermittent mode, leave the TM pin open, and pull the ON/OFF pin up to V
The V
Rev.2.0, Sep.18.2003, page 16 of 37
OFF
(V
BE
ON
is base emitter voltage of internal transistors.
– V
Vref
OFF
3
2
1
0
R
R
0
C
D
= V
V
0.7 V
OFF
BE
). The timing can be programmed as explained below.
1
ON/
(open)
390 k
2.2 k
2.2 F
V
1.4 V
OFF
ON
TM
2
V
ON/
Figure 7.1 Connection Diagram (example)
Figure 6.2 Adjustment of UVL Voltages
+
OFF
3
2.5 V
10 k
R
R
GND
C
3V
V
A
B
ON/
IN
ON/OFF
BE
OFF
V
4
IN
TM
To latch
4.5 V
5
Q
V
2
IN
reference
Vref
Q
I
IN
1
Q
generation
3
On/off hysteresis circuit
Latch
Q
circuit
Vref
S
R
Current
limiter
To other circuitry
CL
Vref output
V
ON
IN
or higher.
ON
and