LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 34

• 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

Application notes - alternative topologies
6
6.1
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Application notes - alternative topologies
Thanks to the wide input voltage range, the adjustable external compensation network and
enhanced dimming capability, the LED5000 is suitable to implement boost and buck-boost
topologies.
Inverting buck-boost
The buck-boost topology fits the application with an input voltage range that overlaps the
output voltage, which is the voltage drop across the LEDs and the sensing resistor.
The inverting buck-boost (see
conversion and it is more efficient than the positive buck-boost. A current generator based
on this topology implies two main application constraints:
●
●
Equation 50
so:
Equation 51
where V
Figure 23. Inverting buck-boost
Example 1
V
IN RANGE
the output voltage is negative so the LEDs must be reversed
the device GND floats with the negative output voltage. The device is supplied between
V
IN
OUT
and V
V
=12-24 V, V
IN
<0.
OUT
I
SW
(<0). As a consequence:
FW_LED
V
IN
=3.7 V, n
=
Doc ID 023951 Rev 1
Figure 23
V
V
IN_MAX LED5000
IN_MAX LED5000
LED
) requires the same component count as the buck
V
= 5 so V
REF
+
=
V
V
OUT
OUT
IN
–
=18.7 V
=
V
OUT
48
+
V
OUT
LED5000
AM13507v1