Datenblatt-pdf.com


iW3623 Schematic ( PDF Datasheet ) - iWatt

Teilenummer iW3623
Beschreibung AC/DC Digital Power Controller
Hersteller iWatt
Logo iWatt Logo 




Gesamt 16 Seiten
iW3623 Datasheet, Funktion
iW3623
AC/DC Digital Power Controller for
High Power Factor Off-Line LED Drivers
1.0 Features
● Isolated AC/DC off-line LED driver
● Power factor > 0.95 for wide input voltage range
100 – 277VAC
● Total harmonic distortion (THD) < 10%
● Under 5% 100Hz/120Hz output current ripple
Resonant control to achieve high efficiency
● LED current foldback with external NTC
● Small size design
xx Small size input bulk capacitor
xx Small size output capacitor
xx Small transformer
Primary-side sensing eliminates the need for
opto-isolator feedback and simplifies design
● Tight LED current regulation ± 5%
● Under 0.5 second start-up time
● Hot-plug LED module support
● Multiple protection features:
xx LED open circuit protection
xx Single-fault protection
xx Over-current protection
xx LED short-circuit protection
xx Current sense-resistor-short-circuit protection
xx Input over-voltage and brown-out protection
2.0 Description
The iW3623 is a high-performance AC/DC off-line power
supply controller for LED luminaires. The iW3623 combines
power factor correction and LED current regulation into one
controller. It achieves PF > 0.95 and THD < 10% for 100–
277VAC input voltage range.
The iW3623 operates in quasi-resonant mode to provide
high efficiency. The device uses iWatt’s advanced primary-
side sensing technology to achieve excellent line and load
regulation without secondary-feedback circuit. In addition,
the iW3623’s pulse-by-pulse waveform analysis technology
allows accurate LED current regulation. The iW3623
maintains stability over all operating conditions without the
need for loop compensation components.
3.0 Applications
● Non-dimmable LED lamps and luminaires
● Optimized for up to 40W output power
Rev. 0.8
iW3623
Preliminary
September 10, 2012
Page 1






iW3623 Datasheet, Funktion
iW3623
AC/DC Digital Power Controller for
High Power Factor Off-Line LED Drivers
6.0 Electrical Characteristics (cont.)
VCC = 12 V, -40°C ≤ TA ≤ 85°C, unless otherwise specified (Note 1)
Parameter
Symbol Test Conditions
ASU SECTION
Maximum operating voltage
Resistance between VCC and ASU
VCC SECTION
Maximum operating voltage
VASU(MAX)
RVCC_ASU
VCC(MAX)
Start-up threshold
Under-voltage lockout threshold
VCC(ST)
VCC(UVL)
Operating current
ASU turn-off threshold
ICCQ
VCC_ASU_OFF
FISENSE SECTION
CC regulation threshold limit
ISENSE short protection reference
Over-current limit threshold
VREG_TH(FLYBACK)
VRSENS(EFLYBACK)
VOCP(FLYBACK)
BISENSE SECTION
ISENSE short protection reference
Over-current limit threshold
VRSENSE(BOOST)
VOCP(BOOST)
VT SECTION
Power limit high threshold (Note 5)
Power limit low threshold (Note 5)
Shutdown threshold (Note 5)
Input leakage current
VP_LIM(HI)
VP_LIM(LO)
VSH_TH
IBVS(VT)
VVT = 1.0V
Min Typ Max Unit
18 V
830 kW
17
11.5 12.5 13.5
6.0 6.5 7.0
6.5
16.25
V
V
V
mA
V
1.4 V
0.16 V
1.5 V
0.15 V
1.9 V
0.56
0.44
0.22
1
V
V
V
µA
Rev. 0.8
iW3623
Preliminary
September 10, 2012
Page 6

6 Page









iW3623 pdf, datenblatt
iW3623
AC/DC Digital Power Controller for
High Power Factor Off-Line LED Drivers
RVIN = 5kΩ / 0.004 – 5kΩ = 1245kΩ
This current represents a stored energy of:
RVCB = 15kΩ / 0.004 – 15kΩ = 3735kΩ
The relationship between VIN and VCB pin voltage for boost
output voltage regulation is:
VCB_A = VIN_A(MAX) + 0.12V
The DC bus voltage is determined by:
E=g
LM
2
× ig _ peak (t)2
(9.4)
When Q1 turns off, ig(t) in LM forces a reversal of polarities on
all windings. Ignoring the communication-time caused by the
leakage inductance LK at the instant of turn-off, the primary
current transfers to the secondary at a peak amplitude of:
VBUS = VCB_A/KCB
VCB_A regulation range is from 0.8V to 1.48V (for example,
when KCB = 0.004, VBUS will be clamped to minimum 0.8/0.004
= 200V).
9.6 Primary Feedback
Figure 9.3 illustrates a simplified flyback converter. When the
switch
drawn
Q1 conducts during TON(t),
from the rectified sinusoid
tvhge(t)c.uTrrheenteing(et)rgisy
directly
Eg(t) is
stored in the magnetizing inductance LM. The rectifying diode
D1 is reverse biased and the load current IO is supplied by
the secondary
and the stored
ceanpeargcyitoErgC(t)O.isWdheelinveQre1dtutronsthoeffo, uDtp1 ucto.nducts
iin(t)
vin(t)
+ ig(t)
vg(t)
TS(t)
N:1 id(t) VO
D1
+
CO
IO
VAUX
VAUX
Q1
id =(t )
NP
NS
× ig _
peak
(t)
(9.5)
Assuming the secondary winding is master and the auxiliary
winding is slave.
VAUX
=
VO
x
NAUX
NS
VAUX
0V
VAUX
=
-VIN
x
NAUX
NP
Figure 9.4 : Auxiliary Voltage Waveforms
The auxiliary voltage is given by:
=VAUX
N AUX
NS
(VO
+ ∆V )
(9.6)
Figure 9.3 : Simplified Flyback Converter
In order to tightly regulate the output voltage, the information
about the output voltage and load current needs to be
accurately sensed. In the DCM flyback converter, this
information can be read via the auxiliary winding or the
primary magnetizing inductance (LM). During the Q1 on-time,
tThheelovaodltacguerreancrtoissssuLpMpilsievdg(ftr)o, mastshuemoiuntgputhtefilvteorltcaagpeadcritooprpCeOd.
across Q1 is zero. The current in Q1 ramps up linearly at a
rate of:
dig (t) = vg (t)
dt LM
(9.2)
At the end of on-time, the current has ramped up to:
and reflects the output voltage as shown in Figure 9.4.
The voltage at the load differs from the secondary voltage by
a diode drop and IR losses. The diode drop is a function of
current, as are IR losses. Thus, if the secondary voltage is
always read at a constant secondary current, the difference
between the output voltage and the secondary voltage is a
fixed ΔV. Furthermore, if the voltage can be read when the
secondary current is small, for example, at the knee of the
auxiliary waveform (see Figure 9.4), then ΔV is also small.
With the iW3623, ΔV can be ignored.
The real-time waveform analyzer in the iW3623 reads the
auxiliary waveform information cycle by cycle. The part then
generates a feedback voltage VFB. The VFB signal precisely
represents the output voltage and is used to regulate the
output voltage.
ig _
peak (t)
=
vg (t) × tON
LM
Rev. 0.8
(9.3)
iW3623
Preliminary
September 10, 2012
Page 12

12 Page





SeitenGesamt 16 Seiten
PDF Download[ iW3623 Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
IW3620Digital PWM Current-Mode ControlleriWatt
iWatt
iW3623AC/DC Digital Power ControlleriWatt
iWatt
iW3623AC/DC Digital Power ControllerDialog Semiconductor
Dialog Semiconductor

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche