LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 41

• Manufacturer Part Number: LED5000PHR
• Description: Current & Power Monitors & Regulators 3A monolithic Conv 850kHz Synch
• Manufacturer: STMicroelectronics

Specifications of LED5000PHR

• Rohs: yes
• Product: Current Regulators
• Supply Voltage - Max: 48 V
• Supply Voltage - Min: 5.5 V
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: HPSO-8
• Accuracy: +/- 3 %
• Input Voltage Range: 5.5 V to 48 V
• Output Current: 23 uA
• Sensing Method: High or Low Side
• Supply Current: 1.7 mA

LED5000
Equation 66
where V
The equations for the floating boost are:
Equation 67
The ideal duty cycle D
Equation 68
As seen for the buck-boost topologies (
the real duty cycle is always higher than the ideal. The real value (that can be measured in
the application) should be used in the following formulas to estimate the switch current.
The peak current flowing in the embedded switch is:
Equation 69
while its average current level is equal to:
Equation 70
This is due to the fact that the current flowing through the internal power switch is delivered
to the output only during the OFF phase.
The switch peak current must be lower than the minimum current limit of the overcurrent
protection (see
current must be lower than the rated DC current of the device.
As a consequence, the maximum output current depends on the application conditions:
Equation 71
where I
The current capability is reduced by the term (1-D
cycle of 0.5, and considering an average current through the switch of 3 A, the maximum
output current deliverable to the load is 1.5 A.
SW MAX
OP_MIN
represents the rated current of the device.
is the minimum operating voltage.
Section Table 5.: Electrical characteristics
I
SW
IDEAL
V
IN_START
=
-------------------------- -
1 D
for the boost converter is:
–
I
LOAD
Doc ID 023951 Rev 1
I
LOAD MAX
REAL
=
V
D
V
+
OP_MIN
IDEAL
I
OUT
SW
I
------------------- -
Chapter 6.1
RIPPLE
I
2
SW MAX
=
=
=
+
-------------------------- -
1 D
----------------------------
1 D
V
V
---------------------------- -
–
I
–
=
DIODE
LOAD
OUT
Application notes - alternative topologies
V
V
-------------------------- -
1 D
REAL
OUT
IN
IDEAL
REAL
–
I
–
LOAD
1 D
and
V
=
–
REAL
IN
) and so, for example, with a duty
5.5V
Chapter 6.2
REAL
for details) while the average
+
+
-------------
2
V
V
IN
DIODE
L
---------
f
), due to power losses
SW
D
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