NCP1910GEVB ON Semiconductor, NCP1910GEVB Datasheet - Page 33

• Manufacturer Part Number: NCP1910GEVB
• Description: BOARD EVAL NCP1910DEMO-B-TLS
• Manufacturer: ON Semiconductor
• Series: -r

Specifications of NCP1910GEVB

• Design Resources: NCP1910 Schematic NCP1910GEVB BOM
• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Power - Output: -
• Voltage - Output: Adj down to 0.8V
• Current - Output: 3A
• Voltage - Input: 3 ~ 5.5 V
• Regulator Topology: Buck
• Frequency - Switching: 1MHz
• Board Type: Fully Populated
• Utilized Ic / Part: NCP1910
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: NCP1910GEVBOS

LLC Soft−Start (SS Pin)
suddenly applying the full current into the resonating circuit.
NCP1910 reserves SS pin to fully discharge soft−start
capacitor before re−start and in case of fault conditions:
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•
•
•
•
•
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soft−start capacitor, it keeps close until V
V
soft−start capacitor before re−start, and hence the fresh
soft−start is confirmed.
SS_RST
In resonant converter, a soft−start is needed to avoid
When the switch inside SS pin is activated to discharge the
LLC brown−out actives,
t
by line brown−out or power good comparator,
CS/FF pin is above V
V
PFC UVP,
Off signal from on/off pin, or
Thermal Shut−Down (TSD)
DEL2
CC
UVLO,
is elapsed, where t
(150 mV typically). It ensures the full discharge of
Feedback
opto−coupler
CS/FF
CS1
DEL2
, the fast fault input for LLC,
V
CS1
timer could be activated
+
−
R
max
Figure 60. The LLC Skip Mode Configuration
Figure 59. The Fast Fault Input at CS/FF pin
PFC_OVP2
V
R
C
”1” to set the SR−latch to
pull low SS pin
CS2
SS
SS
SS
+
−
is below
R
min
Skip
http://onsemi.com
R
SS
t
33
V
Skip
SS pin is released open and the empty soft−start capacitor
withdraws current from R
R
increases the operating frequency of LLC. As the soft−start
capacitor is charged, the LLC driver output frequency
smoothly decreases down to F
feedback loop is supposed to take over the CCO lead as soon
as the output voltage has reached the target.
LLC Skip (Skip Pin, B Version Only)
also to improve the standby power consumption, the
NCP1910B welcomes a skip mode operation (Skip pin)
which permanently observes the opto−coupler collector as
depicted in Figure 60. If skip pin senses a low voltage, it cuts
the LLC output pulses (ML and MU pins) until the collector
goes up again.
SS
Once the LLC part starts operation, the internal switch at
To avoid any frequency runaway in light conditions but
R
S
. This current charges up and soft−start capacitor and
−
+
Q
Q
”1” to disable LLC and PFC driver,
and pull down PFCok
PFC_BO
Grand Reset
Latch
Disable ML and
MU
t
pin through soft−start resistor,
min
. Of course, practically, the