LED5000PHR STMicroelectronics, LED5000PHR Datasheet - Page 18

• 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 - buck conversion
5.7
18/51
With the power components selected in accordance with
and given the BW specification, the components composing the compensation network can
be calculated as:
Equation 16
where the term m
(
R
Equation 17
where K represents the leading position of the F
bandwidth. In general, a value of 2 gives enough phase margin to the overall small loop
transfer function.
Example of system design
Design specification:
V
The inductor and capacitor value are dimensioned to meet the I
Chapter 5.9.2
L=22 H, C
In accordance with
Equation 18
Assuming a system bandwidth of:
Equation 19
the ideal values of the components making up the compensation network is:
Equation 20
Final component selection is based on commercial values and a small capacitor C
added to reduce noise at the error amplifier output. C
margin.
Equation 12
IN
CS
=48 V, V
the current sense gain (
OUT
FW_LED
), R
for output capacitor and inductor selection guidelines):
=1.0 F mlcc (negligible ESR)
S
C
R
the sensing resistor value, G
=3.7 V, n
Chapter 5.9.1
is represented in
C
=
1
---------------------------------------------------------------------------------------------------------- -
+
R
----------------------------------- -
LED
Table 5: Electrical characteristics
LOAD
Doc ID 023951 Rev 1
R
= 10, r
C
L
R
the sensing resistor value is:
BW
=
S
T
Equation 4
43 k
SW
=
LED
C
=
200 mV
------------------- -
C
70 kHz BW
= 1.1
f
1 A
=
P
m
------------------------
R
C
C
m
W
=
C
, R
K
Z
, I
the error amplifier transconductance and
C
1 D
BW
(
200 m
Equation 11
LOAD
LED
–
=
P
MAX
650 pF
slightly decreases the BW and phase
= 1 A, I
–
the equivalent loading resistor
Chapter 5.9: Component selection
0.5
)
LED RIPPLE
LED RIPPLE
) with respect to the system
BW
--------------------------- -
G
m
R
R
CS
S
= 2%
specification (see
LED5000
P
is