TLD5045EJ_15 Datasheet, PDF (21/30 Pages) Infineon Technologies AG – 700mA High Integration - DC/DC Step-Down Converter

Infineon® LITIX™ Power
TLD5045EJ
Application Information
8
Application Information
Note: The following information is given as a hint for the implementation of the device only and shall not be
regarded as a description or warranty of a certain functionality, condition or quality of the device.
8.1
Output Peak current Adjustment via R_SET
The external resistor R_SET is used to adjust the peak current of the regulator. Maximum achievable peak current
is 700mA and minimum achievable peak current is 100mA. The SET pin provides an internally fixed voltage level
at typ.: 1.225V. Out of this considerations the equation is:
(8.1)
Ipeak
=
⎜⎛ ^{1 . 225 V}
⎜
⎝
R _SET
⎟⎞
⎟
⋅
5710
⎠
The factor 5710 is derived from following considerations:
• Ipeak, max = 700mA (R_SET = 10kΩ)
• Ipeak,min = 100mA (R_SET = 70kΩ)
Internal comparator voltage at SET pin = 1.225V.
The circuitry behind the SET pin is adjusting higher peak currents with lower RSET values.
The R_SET value should be in the range from 10kΩ to 70kΩ to achieve the requested peak current range.
The following setup applies for the table displayed in Figure 8-1: V_REC=12V, V_LED=7.2V, L_SW=220µH.
I_PEAK [mA]
100
200
300
400
500
600
700
R_SET [kΩ]
70
35
23
18
14
12
10
Figure 8-1 R_SET Resistor Selection
Data Sheet
21
Revision 1.0
2015-05-28