ha16114pj Renesas Electronics Corporation., ha16114pj Datasheet - Page 17

• Manufacturer Part Number: ha16114pj
• Description: Switching Regulator For Chopper Type Dc/dc Converter
• Manufacturer: Renesas Electronics Corporation.

HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
7.2 Intermittent Mode Timing Diagram (V
7.3 Calculation of Intermittent Mode Timing
Intermittent mode timing is calculated as follows.
(1) T
(2) T
The greater the overload, the sooner the pulse-by-pulse current limiter operates, the smaller t
and from the first equation (1) above, the smaller T
on V
on until T
Rev.2.0, Sep.18.2003, page 17 of 37
IN
ON
OFF
. Note that with the connections shown in the diagram, when V
(time until the IC shuts off when continuous overcurrent occurs)
(time from when the IC shuts off until it next turns on)
T
T
Where V
OFF
ON
OFF
has elapsed.
= C
= C
= C
Note: On duty is the percent of time the IC output is on during one PWM cycle
Sawtooth wave
0.69
Note: 1.
For details, see the overall waveform timing diagram.
ON/
ON/
ON/
BE
PWM output
(In case of HA16114)
OFF
when the pulse-by-pulse current limiter is operating.
OFF
Figure 7.2 Intermittent Mode Timing Diagram (V
OFF
C
0.7 V
V
(See the figure 6.1.)
V
ON/
a.
b.
c.
BE
ON/
R
R
(R
OFF
Continuous overcurrent is detected
Intermittent operation starts (IC is off)
Voltage if overcurrent ends (thick dotted line)
is the base-emitter voltage of internal transistors, and is approximately 0.7 V.
B
OFF
B
A
+ R
ln
ln2
R
3V
B
B
2V
)
BE
2V
V
0 V
V
BE
BE
*1
BE
BE
ln
1
1
On duty*
V
V
IC is on
On duty*
IN
1
IN
ON/
1
OFF
OFF
OFF
OFF
1
2T
Figure 7.3
2V
V
a
ON
BE
ON
only)
BE
On duty*
t
ON
becomes. From the second equation (2), T
1
c
IC is off
T
T
b
ON
c
Dead-band voltage
On
On duty =
Where T = t/f
T
IN
Point at which the current
limiter operates
Off
OFF
is switched on the IC does not turn
ON/
t
ON
OFF
OFF
T
OFF
OFF
OSC
On
only)
100 (%)
t
ON
OFF
becomes,
depends