TLF50281EL Infineon Technologies, TLF50281EL Datasheet - Page 15

• Manufacturer Part Number: TLF50281EL
• Manufacturer: Infineon Technologies

Specifications of TLF50281EL

• Packages: PG-SSOP-14
• Comment: Asyncronous low-Iq-Buck; 5V/500mA; Iq
• Vq (max): 5V
• Iq (max): 500.0 mA
• Iq (typ): 45.0 µA
• Output: Buck Converter

Frequency Variation during PWM/PFM Transition:
Figure 6
in relation to output current and switching frequency. The diagram shows the principle, in reality the signals might
be slightly different. The diagram is without scale in respect of frequency and current values.
The transition from PWM to PFM is shown in a grey line. Starting from right the switching frequency
constant as set by the frequency setting resistor
As soon as the output current
i
output current
monitoring the output voltage
The transition from PFM to PWM is shown in a black line. Starting from left the switching frequency is increasing
with the increasing output current
As soon as the switching frequency is crossing the frequency threshold for transition from PFM to PWM
(which is above the switching frequency
from PFM to PWM.
t
Figure 6
Data Sheet
PWM/PFM
, the regulator will be switched from PWM to PFM mode depending on the output voltage
is showing the transition from Pulse Frequency Modulation to Pulse Width Modulation (and vice versa)
PWM <-> PFM Transitions
I
CC
decreasing, the switching frequency will also decrease, as the pulses are triggered by
V
CC
I
CC
at capacitor
I
PWM to PFM
CC
is below the imaginary current threshold for transition from PWM to PFM
.
f
OSC
set by the frequency setting resistor
i
C
PWM/PFM
OUT
R
FREQ
.
. The output current
15
i
PFM/PWM
PFM to PWM
I
Output Current
CC
f
f
PFM/PWM
(log.scale)
PWM
is decreasing.
R
FREQ
) the regulator will switch
Rev. 1.0, 2011-10-24
Buck Regulator
TLF50281EL
V
CC
. With the
f
PFM/PWM
f
PWM
is