HA16114P View Datasheet(PDF) - Renesas Electronics
Part Name
Description
Manufacturer
HA16114P Datasheet PDF : 38 Pages
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HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
7.2 Intermittent Mode Timing Diagram (VON/OFF only)
3VBE*1
VON/OFF
2VBE
c
c
On
On
VBE
IC is on
IC is off
Off
a
b
0V
TON
t
2TON
TOFF
a. Continuous overcurrent is detected
b. Intermittent operation starts (IC is off)
c. Voltage if overcurrent ends (thick dotted line)
Note: 1. VBE is the base-emitter voltage of internal transistors, and is approximately 0.7 V.
(See the figure 6.1.)
For details, see the overall waveform timing diagram.
Figure 7.2 Intermittent Mode Timing Diagram (VON/OFF only)
7.3 Calculation of Intermittent Mode Timing
Intermittent mode timing is calculated as follows.
(1) TON (time until the IC shuts off when continuous overcurrent occurs)
TON = CON/OFF × RB × ln
2VBE
VBE
×
1
1 − On duty*
= CON/OFF × RB × ln2 ×
1
1 − On duty*
≈ 0.69 × CON/OFF × RB ×
1
1 − On duty*
(2) TOFF (time from when the IC shuts off until it next turns on)
TOFF = CON/OFF × (RA + RB) × ln
VIN − VBE
VIN − 2VBE
Where VBE ≈ 0.7 V
The greater the overload, the sooner the pulse-by-pulse current limiter operates, the smaller tON becomes,
and from the first equation (1) above, the smaller TON becomes. From the second equation (2), TOFF depends
on VIN. Note that with the connections shown in the diagram, when VIN is switched on the IC does not turn
on until TOFF has elapsed.
Sawtooth wave
Dead-band voltage
Point at which the current
PWM output
limiter operates
(In case of HA16114)
tON
On duty = tON × 100 (%)
T
T
Where T = t/fOSC
Note: On duty is the percent of time the IC output is on during one PWM cycle
when the pulse-by-pulse current limiter is operating.
Figure 7.3
Rev.2.0, Sep.18.2003, page 17 of 37
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