TLF50281EL Infineon Technologies, TLF50281EL Datasheet - Page 13

• 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

At point
the duration
At point
V
the internal blocks is reduced. The reference for the output voltage
to
higher than the reference in PWM mode to avoid voltage dumps at the output voltage
steps and to give the regulator more reaction time to switch back to PWM mode.
The regulator is now in PFM mode, the output voltage is
mode.
The output voltage
on-time
C
Figure 4
Data Sheet
PWM/PFM
OUT
V
FB
.
in PWM mode) to
T
t
t
3
. The regulator is now switching internally from PWM to PFM. In PFM mode the power consumption of
4
ON,min
after a normal time period
the output voltage
T
PWM to PFM Transition (Timing Diagram)
ON,min
is triggered. The time between two pulses is depending on the discharging of the output capacitor
D
V
is applied, the output voltage
T
CC
1
T
ON1
PWM
is monitored and as soon as it touches the PFM reference voltage
V
REF_PFM
t
1
T
V
PWM
CC
touches (or exceeds) the voltage threshold for transition from PWM to PFM
(which is equal to
T
T
ON2
D
PWM
i
1
V
2
REF_PFM
as adjusted by the frequency setting resistor
V
CC
t
2
T
keeps on rising. The regulator is still in PWM mode.
V
13
FB
PWM
V
T
in PFM mode). The reference for
REF_PFM
D
ON,min
t
3
3
i
2
t
4
which is equal to
Switch to PFM mode
V
CC
is switched from
V
FB
(or slightly higher) in PFM
V
V
V
V
R
PWM/PFM
REF_PWM
REF_PWM
FREQ
CC
V
i
PWM/PFM
time
time
time
Rev. 1.0, 2011-10-24
REF_PFM
V
due to sudden load
FB
, a further pulse of
i
3
Buck Regulator
in PFM mode is
TLF50281EL
(which is equal
a pulse of the