L6740LTR STMicroelectronics, L6740LTR Datasheet - Page 35

• Manufacturer Part Number: L6740LTR
• Description: IC HYBRID CONTROLLERS 48TQFP
• Manufacturer: STMicroelectronics

Specifications of L6740LTR

• Applications: Hybrid Controllers
• Voltage - Supply: 9 V ~ 15 V
• Current - Supply: 20mA
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFP Exposed Pad, 48-eTQFP, 48-HTQFP, 48-VQFP
• Number Of Outputs: 2
• Output Current: 170 A
• Input Voltage: 13.2 V
• Mounting Style: SMD/SMT
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 497-6298-2

L6740L
rent operation since the current ripple increases. In fact, the ON time increases due to the
OFF time rise because of the current has to reach the I
dition is when the ON time reaches its maximum value (see
pens, the section works in real constant current and the output voltage decrease as the load
increase. Crossing the UV threshold causes the device to latch accordingly.
It can be observed that the peak current (I
determined as follow:
Where V
threshold is crossed, UV is detected. Cycle the power supply or the EN pin to restart opera-
tion.
The maximum average current during the constant-current behavior results (see
in this particular situation, the switching frequency for the NB section results reduced. The
ON time is the maximum allowed T
The trans conductance resistor R
the inductor current ripple valley. Moreover the additional current due to the output filter
charge during on-the-fly VID transitions must be considered.
where I
Figure 14. NB section - constant current operation
I
I
T
R
I
PEAK_NB
MAX_NB
PEAK_NB
I
I
OFF
ISEN
MAX_NB
OCP_NB
=
=
OCP_NB
L
=
OUT(min)
NB
I
-----------------------------------------------------------------
=
T
OCP_NB(max)
ON(max)
I
OCP_NB
I
⋅
OCP_NB
I
----------------------------------------- -
PEAK
T
SW
I
OCTH_NB(min)
is defined above.
LS ON Skipping
V
is the UV threshold, (inductor saturation must be considered). When that
Clock Cycles
+
–
OUT
+
I
----------------------------------------- -
I
OCP_NB
PEAK
V
--------------------------------------- T
⋅
R
IN
dsON(max)
–
L
–
V
2
NB
I
OUT(min)
OCP_NB
T
ON(max)
ISEN
⋅
ON(max)
T
f
SW
=
ON(max)
can be designed considering that the section limits
------------------------------------------ -
T
ON(max)
PEAK_NB
while the OFF time depends on the application:
=
Output voltage monitoring and protections
1
I
+
OCP_NB
T
OFF
) is greater than I
+
OCP_NB
V
--------------------------------------- 0.40 T
IN
0.40 V
–
V
Section
OUT
L
V
NB
IN
OUT(min)
bottom. The worst-case con-
(I
DROOP_NB
Constant Current (Exploded)
I
OCP_NB
OCP_NB
6.8). When this hap-
UVP Threshold
⋅
= 35μA)
Voltage Positioning
but it can be
⋅
SW
Droop Effect
Figure
I
MAX_NB
35/44
14):
I
OUT