TLD5097EL_15 Datasheet, PDF (11/41 Pages) Infineon Technologies AG – Multitopology LITIX Power DC/DC Controller IC

Infineon® LITIX™ Power
TLD5097EL
Switching Regulator
5
Switching Regulator
5.1
Description
The TLD5097EL regulator is suitable for Boost, Buck, Buck-Boost, SEPIC and Flyback configurations. The
constant output current is especially useful for light emitting diode (LED) applications. The switching
regulator function is implemented by a pulse width modulated (PWM) current mode controller.
The PWM current mode controller uses the peak current through the external power switch and error in the
output current to determine the appropriate pulse width duty cycle (on time) for constant output current. The
current mode controller provides a PWM signal to an internal gate driver which then outputs to an external n-
channel enhancement mode metal oxide field effect transistor (MOSFET) power switch.
The current mode controller also has built-in slope compensation to prevent sub-harmonic oscillations which
is a characteristic of current mode controllers operating at high duty cycles (>50% duty).
An additional built-in feature is an integrated soft start that limits the current through the inductor and
external power switch during initialization. The soft start function gradually increases the inductor and switch
current over t_SS (Parameter 5.2.9) to minimize potential overvoltage at the output.
OVFB 9
COMP 8
OV FB
VRef =
1.25V
H when
OVFB >1.25 V
FBH 6
x1
FBL 7
SET ¹⁰
0 if SET < 1.6V
0
VVRef
1
(SET − 0.1V ) _{= VRef}
5
0.3V
FREQ/
SYNC
11
Oscillator
EA
Soft start
gmEA
I EA
Current
Comp
High when
l EA - ISLOPE - ICS > 0
OFF
when H
& ^{Low when}
T_j > 175 °C
R
Q
I ^{Slope Comp}
t
Clock
S^& _Q
Error -FF
High when
IVCC < 4.0V
UV IVCC
NOR
> Output Stage
OFF when
1 ^Low
R
&
= VRef
4.0 V
INV
Q
1
Gate Driver
Supply
Gate
Driver
NAND 2
&
S^& _Q
PWM-FF
Current
Sense
I CS
1 IVCC
2 SWO
4 SWCS
3 SGND
Figure 5-1 Switching Regulator Block Diagram
Data Sheet
11
Revision 1.0
2015-03-12