Synchronization
The power converters can be synchronized to an external clock signal (SYNCI) to improve EMC and EMI
performance and to reduce cross-talk to the loads.
shows the specification of the signal. The clock manager synchronizes the switching frequency to this
signal according to the configuration in the SPI registers. The synchronization functionality is disabled by
default.
To enable synchronization of the switching frequency, an external reference signal is required at the SYNCI pin
and the synchronization functionality must be enabled via SPI. The external clock source must not be removed
while the device is running in synchronized mode.
The device supports a dynamic change of the synchronization frequency during synchronization mode with
minimal disturbance of the output voltage. It is recommended to keep the same phase and change the
switching frequency with the next rising edge of the synchronization signal to minimize the impact on the
output voltage. The output voltage settles within a maximum time of 50 µs.
The synchronization output signal SYNCO can be used to synchronize an external switched-mode post-regulator
to the device. The output frequency is equal to the switching frequency of Buck1. The synchronization signal
has a 50% duty cycle with a selectable phase shift of 0° or 180° with respect to the main clock. The
synchronization output is disabled by default. The synchronization output can be enabled via SPI.
allows to adjust the phase shift between the individual converters. The phase shift is defined between
rising edge of the clock signal and the rising edge of the switch node for the buck converters and the falling
edge of the boost converter respectively. Furthermore the converters Buck1 and Buck2, as well as SYNCO can be
controlled independently with a phase shift of 0° or 180° with respect to the main clock.
Spread spectrum
The device incorporates spread spectrum in order to improve EMC and EMI performance. Spread spectrum is
applied to the main clock source, so it supports all power converters. Spread spectrum is disabled by default.
allows to enable spread spectrum.
5.4.1
Electrical characteristics frequency generation and clock
synchronization
Table 12
Electrical characteristics frequency generation and clock synchronization
T
j
= -40°C to 150°C;
V
R1VSx
= 3.7 V to 35 V; all voltages with respect to ground, positive current flowing into pin
(unless otherwise specified)
Parameter
Symbol
Values
Unit
Note or condition Number
Min.
Typ.
Max.
Internal clock source
Frequency
f
MAIN
1800
2200
2500
kHz
Switching
frequency
selectable via SPI
P_5.4.1
Frequency tolerance
f
MAIN,tol
-10
–
10
%
–
P_5.4.3
Frequency adjustment step
size
f
MAIN,step
–
100
–
kHz
–
P_5.4.4
Synchronization input signal SYNCI
Input level "high"
V
SYNCI, high
0.7
–
–
V
IOVDD
V
SYNCI
increasing
P_5.4.5
OPTIREG
™
PMIC TLF30681QVS01
Power management IC
Central functions
Datasheet
42
Rev. 1.0
2020-04-08
