l6706 STMicroelectronics, l6706 Datasheet - Page 26

• Manufacturer Part Number: l6706
• Description: Vr11.1 Single Phase Controller With Integrated Driver
• Manufacturer: STMicroelectronics

Load transient boost technology
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Load transient boost technology
LTB Technology™ further enhances the performances of dual-edge asynchronous systems
by reducing the system latencies and immediately turning ON the phase to provide the
correct amount of energy to the load.
By properly designing the LTB network, as well as the LTB gain, the undershoot and the
ring-back can be minimized also optimizing the output capacitors count.
LTB Technology™ monitors the output voltage through a dedicated pin (see
detecting Load-Transients with selected dV/dt and turning-on immediately the phase.
It then implements a parallel independent loop that (bypassing error amplifier (E/A)
latencies) reacts to load-transients in very short time (< 150 ns).
LTB Technology™ control loop is reported in
Figure 10. LTB Technology™ control loop
The LTB detector is able to detect output load transients by coupling the output voltage
through an R
then compared with the COMP pin level. The resulting duty-cycle programmed is then OR-
ed with the PWM signal by-passing the main control loop. The phase will then be turned-on
and the EA latencies results bypassed as well.
Short LTB pin to SGND to disable the LTB Technology™: in this condition the device works
as a dual-edge asynchronous PWM controller.
Sensitivity of the load transient detector and the gain of the LTB ramp can be programmed in
order to control precisely both the undershoot and the ring-back.
●
Detector design. R
which is desired the controller to be sensitive as follow:
Z
F
(s)
COMP
LTB
LTB
- C
LTB
LT Detect
FB
network. After detecting a load transient, the LTB ramp is reset and
LTB
R
Ref
LTB
- C
PWM
LTB
Doc ID 15698 Rev 1
LTB Ramp
=
dV
----------------- -
25μA
is design according to the output voltage deviation dV
d V
OUT
COMP
VSEN
Monitor
C
Figure
LTB
PWM_BOOST
GND DROP
RECOVERY
V
PROG
=
Z
FB
10.
---------------------------------------- -
2π R
(s)
LT Detect
⋅
LTB
R
1
LTB
⋅
LTBGAIN
F
SW
C
LTB
L
R
ESR
C
LTBGAIN
O
V
OUT
Figure
11)
L6706
OUT