HA16120FP HITACHI [Hitachi Semiconductor], HA16120FP Datasheet - Page 19

• Manufacturer Part Number: HA16120FP
• Description: Switching Regulator for Chopper Type DC/DC Converter
• Manufacturer: HITACHI [Hitachi Semiconductor]

8. Setting the Overcurrent Detection Threshold
The voltage drop V
typically 200 A. The power MOS FET peak current value before the current limiter goes into operation is
given as follows.
Where, V
Note that R
This filter prevents incorrect operation due to current spikes when the power MOS FET is switched on or
off.
With the values shown in the diagram, the peak current is:
The filter cutoff frequency is calculated as follows:
TH
I
I
f
D
D
F
C
= V
and C
=
=
=
PWM pulse output
(In case of HA16120)
Power MOS FET
drain current (I
(dotted line shows
Current limiter
pin (CL)
Sawtooth wave V
inductor current)
Dead band V
IN
0.2 V
2 C
V
Error output V
TH
– V
F
TH
1
F
V
form a low-pass filter with a cutoff frequency determined by their RC time constant.
CL
IN
at which overcurrent is detected in these ICs is typically 0.2 V. The bias current is
(R
R
Note: This circuit is an example for step-down use.
(240
F
= 0.2 V, V
F
0.2 V
DB
D
R
=
+ R
)
V
E/O
CS
IN
CT
6.28
0.05
CS
+ 0.05 )
To other
circuitry
Figure 8.1 Example for Step-Down Use
200 A
)
1800 pF
I
CL
BCL
is a voltage refered on GND.
1
V
1 k
IN
200 A
240
OUT
HA16114P/PJ/FP/FPJ, HA16120FP/FPJ
IN( )
Figure 7.6
Detector
output
(internal)
= 3.04 A
= 370 kHz
V
CL
TH
+
(CL)
C
F
IC
1800 pF
Example of step-up circuit
V
R
240
C
OUT
I
IN
Determined by L and V
Determined by R
F
L
BCL
C
F
R
G
F
D
F.B.
S
R
0.05
R
CS
I
Inductor
L
CS
D
+
CS
V
and R
IN
V
IN
O
F
V
OUT
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