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PDF IW1699 Data sheet ( Hoja de datos )
| Número de pieza | IW1699 | |
| Descripción | Off-Line Digital Green-Mode Quasi-Resonant PWM Controller | |
| Fabricantes | iWatt | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de IW1699 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
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iW1699
Off-Line Digital Green-Mode Quasi-Resonant PWM Controller
1.0 Features
●● No-load power consumption < 30mW at 230VAC along
with fast dynamic load response and short turn-on
delay time in typical 12W compact adapter/charger
applications
●● Tight constant-voltage and constant-current regulation
across line and load range
●● Primary-side feedback eliminates opto-isolators and
simplifies design
●● Proprietary optimized 89kHz maximum PWM switching
frequency with quasi-resonant operation achieves best
size, efficiency and common mode noise
●● User-configurable 5-level cable drop compensation
provides design flexibility
●● EZ-EMI® design enhances manufacturability
●● Adaptive multi-mode PWM/PFM control improves
efficiency
●● No external loop compensation components required
●● Complies with EPA 2.0 energy-efficiency specifications
with ample margin
●● Built-in single-point fault protection features: output
short-circuit protection, output over-voltage protection,
over-current protection and current-sense-resistor fault
protection
●● Dedicated pins for external over-temperature protection
and over-voltage protection, with latch function available
●● No audible noise over entire operating range
2.0 Description
The iW1699 is a high performance AC/DC power supply
controller which uses digital control technology to build peak
current mode PWM flyback power supplies. The device
operates in quasi-resonant mode to provide high efficiency
along with a number of key built-in protection features
while minimizing the external component count, simplifying
EMI design and lowering the total bill of material cost. The
iW1699 removes the need for secondary feedback circuit
while achieving excellent line and load regulation. It also
eliminates the need for loop compensation components
while maintaining stability over all operating conditions.
Pulse-by-pulse waveform analysis allows for a loop response
that is much faster than traditional solutions, resulting in
improved dynamic load response for both one-time and
repetitive load transients. The built-in power limit function
enables optimized transformer design in universal off-line
applications and allows for a wide input voltage range.
iWatt’s innovative proprietary technology ensures that
power supplies built with the iW1699 can achieve both
highest average active efficiency and less than 30mW
no-load power consumption, and have fast dynamic load
response in a compact form factor in typical 12W and above
applications. The active start-up scheme enables shortest
possible start-up time without sacrificing no-load power loss.
3.0 Applications
●● Compact AC/DC adapter/chargers for media tablets and
smart phones
●● AC/DC adapters for consumer electronics
L
N
+
+ VOUT
RTN
NTC
U1
iW1699
1 VSENSE
VCC 8
2 SD
GND 7
3 CFG
OUTPUT 6
4 ASU
RCDC
ISENSE 5
+
Figure 3.1: iW1699 Typical Application Circuit (Achieving < 30mW No-load Power Consumption)
Rev. 0.4
PRELIMINARY
iW1699
May 3, 2012
iWatt Confidential-Protected By Traceable Watermark
Page 1
Free Datasheet http://www.Datasheet4U.com
1 page  
iW1699
Off-Line Digital Green-Mode Quasi-Resonant PWM Controller
7.0 Typical Performance Characteristics
5.90
5.82
5.74
5.66
5.58
5.50
5.42
5.34
5.26
5.18
5.10
-50
97
-25 0 25 50 75 100 125
Ambient Temperature (ºC)
Figure 7.1 : VCC UVLO vs. Temperature
150
12.10
12.08
12.06
12.04
12.02
12.00
11.98
11.96
11.94
11.92
11.90-50 -25 0 25 50 75 100 125 150
Ambient Temperature (ºC)
Figure 7.2 : Start-Up Threshold vs. Temperature
2.010
93 2.006
89 2.002
85 1.998
81 1.994
77-50 -25 0 25 50 75 100 125 150
Ambient Temperature (ºC)
Figure 7.3 : Switching Frequency vs. Temperature1
1.990-50 -25 0
25 50 75 100 125 150
Ambient Temperature (ºC)
Figure 7.4 : Internal Reference vs. Temperature
105
9.0 104
103
102
6.0 101
100
99
3.0
0.00.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Figure 7.5 : VCC vs. VVCCCCS(uVp)ply Start-up Current
98
97
96
95
-50
-25 0 25 50 75 100 125
Ambient Temperature (ºC)
Figure 7.6 : ISD vs. Temperature
150
Notes:
Note 1. Operating frequency varies based on the load conditions, see Section 9.6 for more details.
Rev. 0.4
PRELIMINARY
iW1699
May 3, 2012
iWatt Confidential-Protected By Traceable Watermark
Page 5
Free Datasheet http://www.Datasheet4U.com
5 Page 
iW1699
Off-Line Digital Green-Mode Quasi-Resonant PWM Controller
9.12 CDC Configuration
9.13 External CFG-Based OVP
The iW1699 incorporates an innovative approach to
allow users to configure cable drop compensation (CDC)
externally. This configuration is only performed once. It
is completed after the initial OTP check but before the
soft-start commences. During the CDC configuration, the
internal digital control block senses the external resistance
value between the CFG pin and ground, and then sets a
corresponding CDC level to allow the device to compensate
for IR drop in the secondary circuitry during normal operation.
Figure 3.1 shows a simple circuit to set CDC level by
connecting a resistor, RCDC, from the CFG pin to ground. The
iW1699 provides five levels of CDC configurations: 0, 75mV,
150mV, 300mV, and 450 mV. Table 9.1 below shows the
resistance range for each of the five CDC levels. In practice,
it is recommended to select resistance in the middle of the
range wherever possible.
In the iW1699, the CFG pin can also be used to provide the
external over-voltage protection (OVP) besides fulfilling the
CDC configuration. This external CFG-based OVP serves
as a supplemental or extra protection in addition to the
VSENSE-based OVP. The circuit implementation can be found
in Figure 9.5, where two resistors R1 and R2 form a voltage
divider to sense output voltage via auxiliary winding, with
the tapping point connected to the CFG pin. During the CDC
configuration the iW1699 does not send out any drive signal
at OUTPUT pin, and the switch Q1 remains in off-state. The
resistors R1 and R2 are essentially connected in parallel
since the bias winding is virtually shorted. Consequently,
the paralleled resistance of R1 and R2 sets the CDC level.
Meanwhile, during normal operation, the CFG pin reflects
output voltage in real-time, in the similar fashion as the
VSENSE does at point 1 in Figure 9.3. The ratio of R1 to R2
sets the external OVP threshold.
The “Cable Comp” specified in Table 9.1 refers to the voltage
increment at PCB end from no-load to full-load conditions
in the CV mode, with the assumption that the secondary
diode voltage drop can be ignored at the point when the
secondary voltage is sensed. Also, the “Cable Comp” is
specified based on the nominal output voltage of 5V. For
different output voltage, the actual voltage increment needs
to be scaled accordingly.
To calculate the amount of cable compensation needed,
take the resistance of the cable and connector and multiply
by the maximum output current.
The resistance values for the resistor divider, R1 and R2,
can be derived as follows.
First, for the given CDC level, the paralleled resistance of R1
and R2 should be within the range listed in Table 9.1:
RCDC
=
R1× R2
R1+ R2
(9.6)
Second, during normal operation the voltage divider, R1 and
R2, sets the desired OVP threshold:
For each of the CDC levels, the internal VSENSE-based OVP
thresholds are different. Table 9.1 also lists the typical OVP
thresholds for each CDC level.
( ) ( )NAUX
NSEC
×VOVP ×
R2
R2 +R1
>= VSD-TH(R)
(9.7)
where NAUX is the number of turns for the bias winding, NSEC
is the number of turns for the secondary winding, VOVP is
Table 9.1: Recommended resistance range and corresponding CDC levels for 5V output
CDC Level
12345
RCDC Range (kΩ)
Cable Comp (mV)
0 – 2.20
0
2.37 – 3.21
75
3.40 – 4.64
150
4.87 – 6.65
300
6.98 – X*
450
VSENSE-based OVP Threshold (V)
1.838
1.861
1.884
1.930
1.976
* The resistance can be as high as 100kΩ, provided CFG pin does not float, which causes device to shut down.
Rev. 0.4
PRELIMINARY
iW1699
May 3, 2012
iWatt Confidential-Protected By Traceable Watermark
Page 11
Free Datasheet http://www.Datasheet4U.com
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet IW1699.PDF ] | |
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