参数资料
| 型号： | LNK501P |
| 厂商： | Power Integrations |
| 文件页数： | 5/20页 |
| 文件大小： | 0K |
| 描述： | IC SWIT OCP CV/CC HV 8DIP |
| 标准包装： | 3,000 |
| 系列： | LinkSwitch® |
| 输出隔离： | 隔离 |
| 频率范围： | 26kHz ~ 46kHz |
| 输出电压： | 700V |
| 功率（瓦特）： | 4W |
| 工作温度： | -40°C ~ 150°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm），7 引线 |
| 供应商设备封装： | DIP-8B |
| 包装： | 管件 |
| 配用： | 596-1001-ND - KIT DESIGN ACCELERATOR ADAPTER |
LNK501
instead placed on the cathode side of D1, it would become a
switching node, generating additional common mode EMI
currents through its internal parasitic capacitance.
The feedback con?guration in Figure 6 is simply a resistive
divider made up of R1 and R3 with D1, R2, C1 and C2 rectifying,
?ltering and smoothing the primary winding voltage signal. The
optocoupler therefore effectively adjusts the resistor divider ratio
to control the DC voltage across R1 and therefore, the feedback
current received by the LinkSwitch CONTROL pin.
When the power supply operates in the constant current (CC)
region, for example when charging a battery, the output voltage
is below the voltage feedback threshold de?ned by U1 and
VR1 and the optocoupler is fully off. In this region, the circuit
behaves exactly as previously described with reference to
Figure 5 where the re?ected voltage increases with increasing
output voltage and the LinkSwitch internal current limit is
adjusted to provide an approximate CC output characteristic.
Note that for similar output characteristics in the CC region,
the value of R1 in Figure 5 will be equal to the value of R1+R3
in Figure 6.
When the output reaches the voltage feedback threshold set by
U1 and VR1, the optocoupler turns on. Any further increase
in the power supply output voltage results in the U1 transistor
current increasing, which increases the percentage of the
re?ected voltage appearing across R1. The resulting increase
in the LinkSwitch CONTROL current reduces the duty cycle
according to Figure 4 and therefore, maintains the output
voltage regulation.
Normally, R1 and R3 are chosen to be equal in value. However,
increasing R3 (while reducing R1 to keep R1 + R3 constant)
increases loop gain in the CV region, improving load regulation.
The extent to which R3 can be increased is limited by opto
transistor voltage and dissipation ratings and should be fully
tested before ?nalizing a design. The values of C2 and C3 are
less important other than to make sure they are large enough
to have very little in?uence on the impedance of the voltage
division circuit set up by R1, R3 and U1 at the switching
frequency. Normally, the values of C2 and C3 in Figure 6 are
chosen equal to the value of C2 in Figure 5, though the voltage
rating may be reduced depending on the relative values of R1
and R2 discussed above. See Applications section for typical
values of components.
Figure 7 shows the in?uence of optocoupler feedback on the
output characteristic. The envelope de?ned by the dashed lines
represent the worst case power supply DC output voltage and
current tolerances (unit-to-unit and over the input voltage
range) if an optocoupler is not used. A typical example of an
inherent (without optocoupler) output characteristic is shown
dotted. This is the characteristic that would result if U1, R4 and
VR1 were removed. The optocoupler feedback results in the
characteristic shown by the solid line. The load variation arrow in
Figure 7 represents the locus of the output characteristic normally
seen during a battery charging cycle. The two characteristics
are identical as the output voltage rises but then separate as
shown when the voltage feedback threshold is reached. This
is the characteristic seen if the voltage feedback threshold is
above the output voltage at the inherent CC to CV transition
point also indicated in Figure 7.
Figure 8 shows a case where the voltage feedback threshold is
set below the voltage at the inherent CC to CV transition point.
In this case, as the output voltage rises, the secondary feedback
circuit takes control before the inherent CC to CV transition
occurs. In an actual battery charging application, this simply
limits the output voltage to a lower value.
OUTPUT VOLTAGE
VOLTAGE
FEEDBACK
THRESHOLD
INHERENT
CC TO CV
TRANSITION
POINT
V O(MAX)
TOLERANCE ENVELOPE
WITHOUT OPTOCOUPLER
TYPICAL INHERENT
CHARACTERISTIC WITHOUT
OPTOCOUPLER
CHARACTERISTIC WITH
OPTOCOUPLER
POWER SUPPLY PEAK
LOAD VARIATION
DURING BATTERY
CHARGING
OUTPUT POWER CURVE
CHARACTERISTIC OBSERVED WITH
LOAD VARIATION OFTEN APPLIED DURING
LABORATORY BENCH TESTING
OUTPUT CURRENT
Figure 8. Output Characteristic with Optocoupler Regulation (Reduced Voltage Feedback Threshold).
PI-2790-112102
I
2/05
5
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LNK501P_1 | 制造商:POWERINT 制造商全称:Power Integrations, Inc. 功能描述:2.2W Cell Phone Charger |
| LNK501PN | 功能描述:交流/直流开关转换器 3W 85-265 VAC 4W 230 VAC RoHS:否 制造商:STMicroelectronics 输出电压:800 V 输入/电源电压（最大值）:23.5 V 输入/电源电压（最小值）:11.5 V 开关频率:115 kHz 电源电流:1.6 mA 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SSO-10 封装:Reel |
| LNK520 | 制造商:POWERINT 制造商全称: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 类别:集成电路 (IC) >> PMIC - AC-DC 转换器，离线开关 系列:LinkSwitch® 标准包装:1 系列:FPS™ 输出隔离:隔离 频率范围:61kHz ~ 73kHz 输入电压:8 V ~ 26 V 输出电压:650V 功率（瓦特）:12W 工作温度:-40°C ~ 115°C 封装/外壳:8-DIP（0.300"，7.62mm） 供应商设备封装:8-MDIP 包装:Digi-Reel® 其它名称:FSL206MRBNFSDKR |
| LNK520GN | 功能描述:交流/直流开关转换器 3W 85-265 VAC 4W 230 VAC RoHS:否 制造商:STMicroelectronics 输出电压:800 V 输入/电源电压（最大值）:23.5 V 输入/电源电压（最小值）:11.5 V 开关频率:115 kHz 电源电流:1.6 mA 工作温度范围:- 40 C to + 150 C 安装风格:SMD/SMT 封装 / 箱体:SSO-10 封装:Reel |
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