TLD5095EL_15 Datasheet, PDF (13/35 Pages) Infineon Technologies AG – Multitopology LITIX Power DC/DC Controller IC

Infineon® LITIX™ Power
TLD5095EL
Oscillator and Synchronisation
6
Oscillator and Synchronisation
Description
R_OSC vs. switching frequency
The internal oscillator is used to determine the switching frequency of the multitopology regulator. The
switching frequency can be selected from 100 kHz to 500 kHz with an external resistor to GND. To set the
switching frequency with an external resistor the following formula can be applied.
( ) R _FREQ
=
1
−
(141
⋅ 10
−12
⎡
⎢⎣
s
Ω
⎤
⎥⎦
)
⋅
⎜⎛
⎝
f _FREQ
⎡
⎢⎣
1
s
⎤
⎥⎦
⎟⎞
⎠
3 .5 ⋅10 ³ [Ω ] [Ω ]
(6.1)
In addition, the oscillator is capable of changing from the frequency set by the external resistor to a synchronized
frequency from an external clock source. If an external clock source is provided on the pin FREQ/SYNC, then the
internal oscillator synchronizes to this external clock frequency and the multitopology regulator switches at the
synchronized frequency. The synchronization frequency capture range is 250 kHz to 500 kHz.
TLD5095
VCLK
FREQ
/ SYNC
R FREQ
Oscillator
C lock Frequency
D etec tor
Multiplexer
PWM
Logic
Gate
Driver
SWO
Oscillator_ BlkDiag_ SyncFixedM ode .vsd
Figure 6-1 Oscillator and Synchronization Block Diagram and Simplified Application Circuit
V_SYNC
V_SYNC,H
V_SYNC,L
T_SYNC = 1 / f_SYNC
t_SYNC,PWH
t
Figure 6-2 Synchronization Timing Diagram
Data Sheet
13
Revision 1.4
2015-03-11