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參數(shù)資料
| 型號(hào)： | LNK501P |
| 廠商： | POWER INTEGRATIONS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Energy Efficient, CV/CC Switcher for Very Low Cost Chargers and Adapters |
| 中文描述： | 0.4 A SWITCHING REGULATOR, 46 kHz SWITCHING FREQ-MAX, PDIP7 |
| 封裝： | PLASTIC, DIP-8 |
| 文件頁數(shù)： | 8/20頁 |
| 文件大小： | 155K |
| 代理商： | LNK501P |
8
F
9/02
LNK501
Continuous mode designs can result in loop instability and
are therefore not recommended.
3. A secondary output of 5 V with a Schottky rectifier diode.
4. Assumed efficiency of 70%
5. The part is board mounted with SOURCE pins soldered to
sufficient area of copper to keep the die temperature at or
below 100
°
C.
In addition to the thermal environment (sealed enclosure,
ventilated, open frame, etc), the maximum power capability of
LinkSwitch
in a given application depends on transformer core
size, efficiency, primary inductance tolerance, minimum
specified input voltage, input storage capacitance, output voltage
output diode forward drop etc., and can be different from the
values shown in Table 1.
In designs not required to meet 300 mW no-load consumption,
the transformer can be designed with higher V
OR
to extend
power capability as noted in the following section.
Transformer Design
To provide an approximately CV/CC output, the transformer
should be designed to be discontinuous; all the energy stored in
the transformer is transferred to the secondary during the
MOSFET off time. Energy transfer in discontinuous mode is
independent of line voltage.
The peak power point prior to entering constant current operation
is defined by the maximum power transferred by the transformer.
The power transferred is given by the expression P = 0.5·L·I
2
·f,
where L is the primary inductance, I
2
is the primary peak current
squared and f is the switching frequency.
To simplify analysis, the data sheet parameter table specifies an
I
2
f coefficient. This is the product of current limit squared and
switching frequency normalized to the feedback parameter
I
. This provides a single term that specifies the variation of
the peak power point in the power supply due to
LinkSwitch
.
As primary inductance tolerance is part of the expression that
determines the peak output power point (start of the CC
characteristic) this parameter should be well controlled. For an
estimated overall output peak power tolerance of
±
20% the
primary inductance tolerance should be
±
10% or better. This is
achievable using standard low cost, center leg gapping techniques
where the gap size is typically 0.08 mm or larger. Smaller gap
sizes are possible but require non standard, tighter ferrite A
L
tolerances.
Other gapping techniques such as film gapping allow tighter
tolerances (
±
7% or better) with associated improvements in the
tolerance of the peak power point. Please consult your
transformer vendor for guidance.
Core gaps should be uniform. Uneven core gapping, especially
with small gap sizes, may cause variation in the primary
inductance with flux density (partial saturation) and make the
constant current region non-linear. To verify uniform gapping
it is recommended that the primary current wave-shape be
examined while feeding the supply from a DC source. The
gradient is defined as di/dt = V/L and should remain constant
throughout the MOSFET on time. Any change in gradient of
the current ramp is an indication of uneven gapping.
Measurements made using a LCR bridge should not be solely
relied upon; typically these instruments only measure at currents
of a few milliamps. This is insufficient to generate high enough
flux densities in the core to show uneven gapping.
For a typical EE13 core using center leg gapping, a 0.08 mm gap
(A
of 190 nH/t
2
) allows a primary inductance tolerance of
±
10% to be maintained in standard high volume production.
This allows the EE13 to be used in designs up to 2.75 W. If film
gapping is used then this increases to 3 W with less than
300 mW no-load consumption. Moving to a larger core, EE16
for example, allows a 3 W output with center leg gapping.
The transformer turns ratio should be selected to give a V
(output voltage reflected through secondary to primary turns
ratio) of 40 - 60 V. In designs not required to meet 300 mW no-
load consumption targets, the transformer can be designed with
higher V
as long as discontinuous mode operation is
maintained. This increases the output power capability. For
example, a 230 VAC input design using an EE19 transformer
core with V
>70 V, is capable of delivering up to 5 W typical
output power. Note: the linearity of the CC region of the power
supply output characteristic is influenced by V
. If this is an
important aspect of the application, the output characteristic
should be checked before finalizing the design.
Output Characteristic Variation
Both the device tolerance and external circuit govern the overall
tolerance of the
LinkSwitch
output characteristic. Estimated
peak power point tolerances for a 2.75 W design are
±
10% for
voltage and
±
20% for current limit for overall variation in high
volume manufacturing. This includes device and transformer
tolerances and line variation. Lower power designs may have
poorer constant current linearity.
As the output load reduces from the peak power point, the
output voltage will tend to rise due to tracking errors compared
to the load terminals. Sources of these errors include the output
cable drop, output diode forward voltage and leakage inductance,
which is the dominant cause. As the load reduces, the primary
operating peak current reduces, together with the leakage
inductance energy, which reduces the peak charging of the
clamp capacitor. With a primary leakage inductance of 50
μ
H,
the output voltage typically rises 30% over a 100% to 5% load
change.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LNK501P_1 | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:2.2W Cell Phone Charger |
| LNK501PN | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 3W 85-265 VAC 4W 230 VAC RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
| LNK520 | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:Energy Efficient, CV or CV/CC Switcher for Very Low Cost Adapters and Chargers |
| LNK520G | 功能描述:IC SWIT OCP CV/CC HV 8SMD RoHS:否 類別:集成電路 (IC) >> PMIC - AC-DC 轉(zhuǎn)換器，離線開關(guān) 系列:LinkSwitch® 標(biāo)準(zhǔn)包裝:1 系列:FPS™ 輸出隔離:隔離 頻率范圍:61kHz ~ 73kHz 輸入電壓:8 V ~ 26 V 輸出電壓:650V 功率（瓦特）:12W 工作溫度:-40°C ~ 115°C 封裝/外殼:8-DIP（0.300"，7.62mm） 供應(yīng)商設(shè)備封裝:8-MDIP 包裝:Digi-Reel® 其它名稱:FSL206MRBNFSDKR |
| LNK520GN | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 3W 85-265 VAC 4W 230 VAC RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
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