NCP1631DR2G ON Semiconductor, NCP1631DR2G Datasheet - Page 17
NCP1631DR2G
Manufacturer Part Number
NCP1631DR2G
Description
IC CTLR PFC INTERLEAVED 16SOIC
Manufacturer
ON Semiconductor
Datasheet
1.NCP1631DR2G.pdf
(23 pages)
Specifications of NCP1631DR2G
Mode
Critical Conduction (CRM), Discontinuous Conduction (DCM)
Frequency - Switching
130kHz
Current - Startup
100µA
Voltage - Supply
10 V ~ 15 V
Operating Temperature
-40°C ~ 125°C
Mounting Type
Surface Mount
Package / Case
16-SOIC (3.9mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
NCP1631DR2G
Manufacturer:
ON/安森美
Quantity:
20 000
Frequency Foldback
function to improve the light load efficiency. Practically,
the oscillator charge and discharge currents (I
I
the power level. More specifically, I
I
the regulation block that thanks to the feed−forward
featured by the NCP1631, is representative of the load.
function of V
increasing function of V
OSC(DISCH)
OSC(DISCH)
In addition, the circuit features the frequency fold−back
The practical implementation is portrayed by Figure 16.
The oscillator charge current is then an increasing function of V
The oscillator discharge current is:
The oscillator discharge current is also an increasing
As a consequence, the clamp frequency is also an
of Figure 16) are not constant but dependent on
linearly vary as a function of V
REGUL
Figure 17. Typical Waveforms (T
and is clamped to105 mA.
REGUL
until it reaches a maximum
control
OSC(CH)
OSC(CH)
I
I
I
I
OSC(CH)
OSC(CH)
OSC(DISCH)
OSC(DISCH)
output of
http://onsemi.com
delay
and
and
+ I
+ I
not shown here for the sake of simplicity)
+
+ I
OSC(clamp)
OSC(clamp)
17
V
OSC(DISCH1)
REGUL
R
effectively used to modulate the MOSFET on−time.
V
fold−back” pin). A resistor R
to sink a current proportional to V
This current is clamped not to exceed 105 mA and copied
by a current mirror to form I
value for (I
frequency f
value obtained at full load and if we name it “f
FF
REGUL
“V
As a matter of fact, the oscillator charge current is:
REGUL
REGUL
)
) I
V
OSC(CH1)
I
is buffered and applied to pin 6 (“Frequency
pin6
REGUL
R
and is clamped to 140 mA.
+ 105 mA
” is the signal derived from V
OSC
FF
FF
+ I
= 105 mA). If we consider the clamp
computed by Equation 17 as the nominal
FF
+ I
+
OSC(CHT1)
if
if
V
REGUL
R
V
V
FF
REGUL
REGUL
R
R
FF
FF
OSC(CH)
FF
+ 140 mA
.
is to be connected to pin 6
v 105 mA
v 105 mA
REGUL
and I
OSC(DISCH)
control
otherwise
otherwise
OSC(nom)
(eq. 18)
(eq. 19)
that is
.
”: