LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 39

• 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 61
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 is:
Equation 62
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.
Figure 29
boost topology. The input voltage ranges from 18 to 30 V and it can drive a string composed
of 7 LEDs with 0.7 A DC (V
The network D5, R4, R
be neglected during the normal operation since the FB biasing current is negligible (tens of
nA, see
D5. In case the load is disconnected or in case of open LED:
Equation 63
R4 must be dimensioned to limit the D5 rated power so it is an inexpensive small signal
Zener diode.
Figure 29. LED current source based on positive BB+ topology
GND
DIM
VIN
INH
SW MAX
Table 5: Electrical characteristics
10uF
shows the circuit schematic for an LED current source based on positive buck-
TP1
TP2
TP4
C1
TP6
10uF
C2
100nF
represents the rated current of the device.
Section Table 5.: Electrical characteristics
C3
R1
JP2
JP1
10k
S
R2
NM
implements an inexpensive overvoltage protection. R4 effect can
FW_LED
1
2
7
3
Doc ID 023951 Rev 1
I
LOAD MAX
U1
BOOT
DIM
VIN
INH
V
GND
6
C6
OUT
I
EP
ZENER_DIODE
= 3.75 V so V
EP
LED5000
I
SW
=
100nF
R3
10K
C4
1.5nF
COMP
SW
4
FB
V
I
) but it limits the current flowing in the zener diode
SW MAX
FB
=
C5
15pF
8
5
-------------------------- -
1 D
+
–
I
V
LOAD
Application notes - alternative topologies
=
ZENER_DIODE
OUT
REAL
-------------------- -
R
REAL
S
V
1 D
=26.4 V).
+
FB
–
XAL6060-22uH
R5
NM
STN3NF06L
R8
10k
R
) and so, for example, with a duty
4
L1
REAL
R6
100
for details) while the average
Q1
C9
1nF
2
D3
R7
NM
STPS3L60U
C10
NM
small signal
power plane
1
D5
R4
NM
C7
0.28R
RS
10k
C8
2.2uF
50V
TP3
TP5
TP7
VLED+
VLED-
GND
AM13513v1
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